Journal articles on the topic 'Neural processing latencies'
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1
Zhang, Ruohan, and Dana H. Ballard. "Parallel Neural Multiprocessing with Gamma Frequency Latencies." Neural Computation 32, no. 9 (September 2020): 1635–63. http://dx.doi.org/10.1162/neco_a_01301.
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The Poisson variability in cortical neural responses has been typically modeled using spike averaging techniques, such as trial averaging and rate coding, since such methods can produce reliable correlates of behavior. However, mechanisms that rely on counting spikes could be slow and inefficient and thus might not be useful in the brain for computations at timescales in the 10 millisecond range. This issue has motivated a search for alternative spike codes that take advantage of spike timing and has resulted in many studies that use synchronized neural networks for communication. Here we focus on recent studies that suggest that the gamma frequency may provide a reference that allows local spike phase representations that could result in much faster information transmission. We have developed a unified model (gamma spike multiplexing) that takes advantage of a single cycle of a cell's somatic gamma frequency to modulate the generation of its action potentials. An important consequence of this coding mechanism is that it allows multiple independent neural processes to run in parallel, thereby greatly increasing the processing capability of the cortex. System-level simulations and preliminary analysis of mouse cortical cell data are presented as support for the proposed theoretical model.
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Ro, Tony. "Alpha Oscillations and Feedback Processing in Visual Cortex for Conscious Perception." Journal of Cognitive Neuroscience 31, no. 7 (July 2019): 948–60. http://dx.doi.org/10.1162/jocn_a_01397.
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Variability in perception between individuals may be a consequence of different inherent neural processing speeds. To assess whether alpha oscillations systematically reflect a feedback pacing mechanism for cortical processing during visual perception, comparisons were made between alpha oscillations, visual suppression from TMS, visual evoked responses, and metacontrast masking. Peak alpha oscillation frequencies, measured through scalp EEG recordings, significantly correlated with the optimum latencies for visual suppression from TMS of early visual cortex. Individuals with shorter alpha periods (i.e., higher peak alpha frequencies) processed visual information faster than those with longer alpha periods (i.e., lower peak alpha frequencies). Moreover, peak alpha oscillation periods and optimum TMS visual suppression latencies predicted the latencies of late but not early visual evoked responses. Together, these findings demonstrate an important role of alpha oscillatory and late feedback activity in visual cortex for conscious perception. They also show that the timing for visual awareness varies across individuals, depending on the pace of one's endogenous oscillatory cycling frequency.
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Nakata, Hiroki, Misaki Oshiro, Mari Namba, and Manabu Shibasaki. "Effects of passive heat stress on human somatosensory processing." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 309, no. 11 (December 1, 2015): R1387—R1396. http://dx.doi.org/10.1152/ajpregu.00280.2015.
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Herein, we investigated the effects of passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs). Fifteen healthy subjects received a median nerve stimulation at the left wrist under two thermal conditions: Heat Stress and normothermic Time Control. The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4′ and P14, N18, P22, and N30 at Fz were evaluated. Under the Heat Stress condition, SEPs were recorded at normothermic baseline (1st), early in heat stress (2nd), when esophageal temperature had increased by ∼1.0°C (3rd) and ∼2.0°C (4th), and after heat stress (5th). In the Time Control condition, SEPs were measured at the same time intervals as those in the Heat Stress condition. The peak latencies and amplitudes of SEPs did not change early in heat stress. However, the latencies of P14, N20, and N60 at C4′ and P14, N18, and P22 at Fz were significantly shorter in the 4th session than in the 1st session. Furthermore, the peak amplitudes of P25 and N60 at C4′, and P22 and N30 at Fz decreased with increases in body temperature. On the other hand, under the Time Control condition, no significant differences were observed in the amplitudes or latencies of any component of SEPs. These results suggested that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and hyperthermia impaired the neural activity of cortical somatosensory processing.
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Weber-Fox, Christine, and Helen J. Neville. "Sensitive Periods Differentiate Processing of Open- and Closed-Class Words." Journal of Speech, Language, and Hearing Research 44, no. 6 (December 2001): 1338–53. http://dx.doi.org/10.1044/1092-4388(2001/104).
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The goal of this study was to test the hypothesis that neural processes for language are heterogeneous in their adaptations to maturation and experience. This study examined whether the neural processes for open-and closed-class words are differentially affected by delays in second-language immersion. In English, open-class words primarily convey referential meaning, whereas closed-class words are primarily related to grammatical information in sentence processing. Previous studies indicate that event-related brain potentials (ERPs) elicited by these word classes display nonidentical distributions and latencies, show different developmental time courses, and are differentially affected by early language experience in Deaf individuals. In this study, ERPs were recorded from 10 monolingual English speakers and 53 Chinese-English bilingual speakers who were grouped according to their age of immersion in English: 1–3, 4–6, 7–10, 11–13, and >15 years of age. Closed-class words elicited an N280 that was largest over left anterior electrode sites for all groups. However, the peak latency was later (>35 ms) in bilingual speakers immersed in English after 7 years of age. In contrast, the latencies and distributions of the N350 elicited by open-class words were similar in all groups. In addition, the N400, elicited by semantic anomalies (open-class words that violated semantic expectation), displayed increased peak latencies for only the later-learning bilingual speakers (>11 years). These results are consistent with the hypothesis that language subprocesses are differentially sensitive to the timing of second-language experience.
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Ansari, M. S., R. Rangasayee, and M. A. H. Ansari. "Neurophysiological aspects of brainstem processing of speech stimuli in audiometric-normal geriatric population." Journal of Laryngology & Otology 131, no. 3 (December 23, 2016): 239–44. http://dx.doi.org/10.1017/s0022215116009841.
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AbstractObjective:Poor auditory speech perception in geriatrics is attributable to neural de-synchronisation due to structural and degenerative changes of ageing auditory pathways. The speech-evoked auditory brainstem response may be useful for detecting alterations that cause loss of speech discrimination. Therefore, this study aimed to compare the speech-evoked auditory brainstem response in adult and geriatric populations with normal hearing.Methods:The auditory brainstem responses to click sounds and to a 40 ms speech sound (the Hindi phoneme |da|) were compared in 25 young adults and 25 geriatric people with normal hearing. The latencies and amplitudes of transient peaks representing neural responses to the onset, offset and sustained portions of the speech stimulus in quiet and noisy conditions were recorded.Results:The older group had significantly smaller amplitudes and longer latencies for the onset and offset responses to |da| in noisy conditions. Stimulus-to-response times were longer and the spectral amplitude of the sustained portion of the stimulus was reduced. The overall stimulus level caused significant shifts in latency across the entire speech-evoked auditory brainstem response in the older group.Conclusion:The reduction in neural speech processing in older adults suggests diminished subcortical responsiveness to acoustically dynamic spectral cues. However, further investigations are needed to encode temporal cues at the brainstem level and determine their relationship to speech perception for developing a routine tool for clinical decision-making.
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Han, Ji-Hye, Jihyun Lee, and Hyo-Jeong Lee. "Noise-Induced Change of Cortical Temporal Processing in Cochlear Implant Users." Clinical and Experimental Otorhinolaryngology 13, no. 3 (August 1, 2020): 241–48. http://dx.doi.org/10.21053/ceo.2019.01081.
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Objectives. Cochlear implant (CI) users typically report impaired ability to understand speech in noise. Speech understanding in CI users decreases with noise due to reduced temporal processing ability, and speech perceptual errors involve stop consonants distinguished by voice onset time (VOT). The current study examined the effects of noise on various speech perception tests while at the same time used cortical auditory evoked potentials (CAEPs) to quantify the change of neural processing of speech sounds caused by noise. We hypothesized that the noise effects on VOT processing can be reflected in N1/P2 measures, the neural changes relate to behavioral speech perception performances.Methods. Ten adult CI users and 15 normal-hearing (NH) people participated in this study. CAEPs were recorded from 64 scalp electrodes in both quiet and noise (signal-to-noise ratio +5 dB) and in passive and active (requiring consonant discrimination) listening. Speech stimulus was synthesized consonant-vowels with VOTs of 0 and 50 ms. N1-P2 amplitudes and latencies were analyzed as a function of listening condition. For the active condition, the P3b also was analyzed. Behavioral measures included a variety of speech perception tasks.Results. For good performing CI users, performance in most speech test was lower in the presence of noise masking. N1 and P2 latencies became prolonged with noise masking. The P3b amplitudes were smaller in CI groups compared to NH. The degree of P2 latency change (0 vs. 50 ms VOT) was correlated with consonant perception in noise.Conclusion. The effects of noise masking on temporal processing can be reflected in cortical responses in CI users. N1/P2 latencies were more sensitive to noise masking than amplitude measures. Additionally, P2 responses appear to have a better relationship to speech perception in CI users compared to N1.
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Nakata, Hiroki, Mari Namba, Ryusuke Kakigi, and Manabu Shibasaki. "Effects of face/head and whole body cooling during passive heat stress on human somatosensory processing." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 312, no. 6 (June 1, 2017): R996—R1003. http://dx.doi.org/10.1152/ajpregu.00039.2017.
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We herein investigated the effects of face/head and whole body cooling during passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs) at C4′ and Fz electrodes. Fourteen healthy subjects received a median nerve stimulation at the left wrist. SEPs were recorded at normothermic baseline (Rest), when esophageal temperature had increased by ~1.2°C (heat stress: HS) during passive heating, face/head cooling during passive heating (face/head cooling: FHC), and after HS (whole body cooling: WBC). The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4′ and P14, N18, P22, and N30 at Fz were evaluated. Latency indicated speed of the subcortical and cortical somatosensory processing, while amplitude reflected the strength of neural activity. Blood flow in the internal and common carotid arteries (ICA and CCA, respectively) and psychological comfort were recorded in each session. Increases in esophageal temperature due to HS significantly decreased the amplitude of N60, psychological comfort, and ICA blood flow in the HS session, and also shortened the latencies of SEPs (all, P < 0.05). While esophageal temperature remained elevated, FHC recovered the peak amplitude of N60, psychological comfort, and ICA blood flow toward preheat baseline levels as well as WBC. However, the latencies of SEPs did not recover in the FHC and WBC sessions. These results suggest that impaired neural activity in cortical somatosensory processing during passive HS was recovered by FHC, whereas conduction velocity in the ascending somatosensory input was accelerated by increases in body temperature.
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O’Brien, Jennifer L., Dee A. Nikjeh, and Jennifer J. Lister. "Interaction of Musicianship and Aging: A Comparison of Cortical Auditory Evoked Potentials." Behavioural Neurology 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/545917.
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Objective. The goal of this study was to begin to explore whether the beneficial auditory neural effects of early music training persist throughout life and influence age-related changes in neurophysiological processing of sound.Design. Cortical auditory evoked potentials (CAEPs) elicited by harmonic tone complexes were examined, including P1-N1-P2, mismatch negativity (MMN), and P3a.Study Sample. Data from older adult musicians (n=8) and nonmusicians (n=8) (ages 55–70 years) were compared to previous data from young adult musicians (n=40) and nonmusicians (n=20) (ages 18–33 years).Results. P1-N1-P2 amplitudes and latencies did not differ between older adult musicians and nonmusicians; however, MMN and P3a latencies for harmonic tone deviances were earlier for older musicians than older nonmusicians. Comparisons of P1-N1-P2, MMN, and P3a components between older and young adult musicians and nonmusicians suggest that P1 and P2 latencies are significantly affected by age, but not musicianship, while MMN and P3a appear to be more sensitive to effects of musicianship than aging.Conclusions. Findings support beneficial influences of musicianship on central auditory function and suggest a positive interaction between aging and musicianship on the auditory neural system.
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Nakata, Hiroki, Misaki Oshiro, Mari Namba, and Manabu Shibasaki. "Effects of aerobic exercise under different thermal conditions on human somatosensory processing." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 311, no. 4 (October 1, 2016): R629—R636. http://dx.doi.org/10.1152/ajpregu.00153.2016.
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The present study aimed to investigate the effects of aerobic exercise on human somatosensory processing recorded by somatosensory evoked potentials (SEPs) under temperate [TEMP, 20°C and 40% relative humidity (RH)] and hot (HOT, 35°C and 30% RH) environments. Fifteen healthy subjects performed 4 × 15-min bouts of a moderate cycling exercise [mean power output: 156.5 ± 7.7 (SE) W], with a 10-min rest period and received a posterior tibial nerve stimulation at the left ankle before and after each exercise bout; SEPs were recorded in five sessions; 1st (pre), 2nd (post-1st exercise bout), 3rd (post-2nd exercise bout), 4th (post-3rd exercise bout), and 5th (post-4th exercise bout). The peak latencies and amplitudes of the P37, N50, P60, and N70 components at Cz were evaluated. The latencies of P37, N50, P60, and N70 were significantly shorter with the repetition of aerobic exercise, and these shortened latencies were significantly greater in the HOT condition than in the TEMP condition (P37: 3rd, P < 0.05, and 5th, P < 0.01; P60: 4th, P < 0.05, and 5th, P < 0.01; N70: 4th, P < 0.05, and 5th, P < 0.001). No significant differences were observed in the amplitudes of any SEP component under either thermal condition. These results suggest that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and aerobic exercise did not alter the strength of neural activity in cortical somatosensory processing.
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Kuśmierek, Paweł, and Josef P. Rauschecker. "Selectivity for space and time in early areas of the auditory dorsal stream in the rhesus monkey." Journal of Neurophysiology 111, no. 8 (April 15, 2014): 1671–85. http://dx.doi.org/10.1152/jn.00436.2013.
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The respective roles of ventral and dorsal cortical processing streams are still under discussion in both vision and audition. We characterized neural responses in the caudal auditory belt cortex, an early dorsal stream region of the macaque. We found fast neural responses with elevated temporal precision as well as neurons selective to sound location. These populations were partly segregated: Neurons in a caudomedial area more precisely followed temporal stimulus structure but were less selective to spatial location. Response latencies in this area were even shorter than in primary auditory cortex. Neurons in a caudolateral area showed higher selectivity for sound source azimuth and elevation, but responses were slower and matching to temporal sound structure was poorer. In contrast to the primary area and other regions studied previously, latencies in the caudal belt neurons were not negatively correlated with best frequency. Our results suggest that two functional substreams may exist within the auditory dorsal stream.
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Siveke, Ida, Christian Leibold, Katharina Kaiser, Benedikt Grothe, and Lutz Wiegrebe. "Level-Dependent Latency Shifts Quantified Through Binaural Processing." Journal of Neurophysiology 104, no. 4 (October 2010): 2224–35. http://dx.doi.org/10.1152/jn.00392.2010.
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The mammalian binaural system compares the timing of monaural inputs with microsecond precision. This temporal precision is required for localizing sounds in azimuth. However, temporal features of the monaural inputs, in particular their latencies, highly depend on the overall sound level. In a combined psychophysical, electrophysiological, and modeling approach, we investigate how level-dependent latency shifts of the monaural responses are reflected in the perception and neural representation of interaural time differences. We exploit the sensitivity of the binaural system to the timing of high-frequency stimuli with binaurally incongruent envelopes. Using these novel stimuli, both the perceptually adjusted interaural time differences and the time differences extracted from electrophysiological recordings systematically depend on overall sound pressure level. The perceptual and electrophysiological time differences of the envelopes can be explained in an existing model of temporal integration only if a level-dependent firing threshold is added. Such an adjustment of firing threshold provides a temporally accurate neural code of the temporal structure of a stimulus and its binaural disparities independent of overall sound level.
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Marquez, Bicky A., Matthew J. Filipovich, Emma R. Howard, Viraj Bangari, Zhimu Guo, Hugh D. Morison, Thomas Ferreira De Lima, Alexander N. Tait, Paul R. Prucnal, and Bhavin J. Shastri. "Silicon photonics for artificial intelligence applications." Photoniques, no. 104 (September 2020): 40–44. http://dx.doi.org/10.1051/photon/202010440.
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Artificial intelligence enabled by neural networks has enabled applications in many fields (e.g. medicine, finance, autonomous vehicles). Software implementations of neural networks on conventional computers are limited in speed and energy efficiency. Neuromorphic engineering aims to build processors in which hardware mimic neurons and synapses in brain for distributed and parallel processing. Neuromorphic engineering enabled by silicon photonics can offer subnanosecond latencies, and can extend the domain of artificial intelligence applications to high-performance computing and ultrafast learning. We discuss current progress and challenges on these demonstrations to scale to practical systems for training and inference.
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Vibell, J., C. Klinge, M. Zampini, C. Spence, and A. C. Nobre. "Temporal Order is Coded Temporally in the Brain: Early Event-related Potential Latency Shifts Underlying Prior Entry in a Cross-modal Temporal Order Judgment Task." Journal of Cognitive Neuroscience 19, no. 1 (January 2007): 109–20. http://dx.doi.org/10.1162/jocn.2007.19.1.109.
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The speeding-up of neural processing associated with attended events (i.e., the prior-entry effect) has long been proposed as a viable mechanism by which attention can prioritize our perception and action. In the brain, this has been thought to be regulated through a sensory gating mechanism, increasing the amplitudes of early evoked potentials while leaving their latencies unaffected. However, the majority of previous research has emphasized speeded responding and has failed to emphasize fine temporal discrimination, thereby potentially lacking the sensitivity to reveal putative modulations in the timing of neural processing. In the present study, we used a cross-modal temporal order judgment task while shifting attention between the visual and tactile modalities to investigate the mechanisms underlying selective attention electrophysiologically. Our results indicate that attention can indeed speed up neural processes during visual perception, thereby providing the first electrophysiological support for the existence of prior entry.
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Bsharat-Maalouf, Dana, and Hanin Karawani. "Bilinguals’ speech perception in noise: Perceptual and neural associations." PLOS ONE 17, no. 2 (February 23, 2022): e0264282. http://dx.doi.org/10.1371/journal.pone.0264282.
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The current study characterized subcortical speech sound processing among monolinguals and bilinguals in quiet and challenging listening conditions and examined the relation between subcortical neural processing and perceptual performance. A total of 59 normal-hearing adults, ages 19–35 years, participated in the study: 29 native Hebrew-speaking monolinguals and 30 Arabic-Hebrew-speaking bilinguals. Auditory brainstem responses to speech sounds were collected in a quiet condition and with background noise. The perception of words and sentences in quiet and background noise conditions was also examined to assess perceptual performance and to evaluate the perceptual-physiological relationship. Perceptual performance was tested among bilinguals in both languages (first language (L1-Arabic) and second language (L2-Hebrew)). The outcomes were similar between monolingual and bilingual groups in quiet. Noise, as expected, resulted in deterioration in perceptual and neural responses, which was reflected in lower accuracy in perceptual tasks compared to quiet, and in more prolonged latencies and diminished neural responses. However, a mixed picture was observed among bilinguals in perceptual and physiological outcomes in noise. In the perceptual measures, bilinguals were significantly less accurate than their monolingual counterparts. However, in neural responses, bilinguals demonstrated earlier peak latencies compared to monolinguals. Our results also showed that perceptual performance in noise was related to subcortical resilience to the disruption caused by background noise. Specifically, in noise, increased brainstem resistance (i.e., fewer changes in the fundamental frequency (F0) representations or fewer shifts in the neural timing) was related to better speech perception among bilinguals. Better perception in L1 in noise was correlated with fewer changes in F0 representations, and more accurate perception in L2 was related to minor shifts in auditory neural timing. This study delves into the importance of using neural brainstem responses to speech sounds to differentiate individuals with different language histories and to explain inter-subject variability in bilinguals’ perceptual abilities in daily life situations.
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Karns, Christina M., and Robert T. Knight. "Intermodal Auditory, Visual, and Tactile Attention Modulates Early Stages of Neural Processing." Journal of Cognitive Neuroscience 21, no. 4 (April 2009): 669–83. http://dx.doi.org/10.1162/jocn.2009.21037.
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We used event-related potentials (ERPs) and gamma band oscillatory responses (GBRs) to examine whether intermodal attention operates early in the auditory, visual, and tactile modalities. To control for the effects of spatial attention, we spatially coregistered all stimuli and varied the attended modality across counterbalanced blocks in an intermodal selection task. In each block, participants selectively responded to either auditory, visual, or vibrotactile stimuli from the stream of intermodal events. Auditory and visual ERPs were modulated at the latencies of early cortical processing, but attention manifested later for tactile ERPs. For ERPs, auditory processing was modulated at the latency of the Na (29 msec), which indexes early cortical or thalamocortical processing and the subsequent P1 (90 msec) ERP components. Visual processing was modulated at the latency of the early phase of the C1 (62–72 msec) thought to be generated in the primary visual cortex and the subsequent P1 and N1 (176 msec). Tactile processing was modulated at the latency of the N160 (165 msec) likely generated in the secondary association cortex. Intermodal attention enhanced early sensory GBRs for all three modalities: auditory (onset 57 msec), visual (onset 47 msec), and tactile (onset 27 msec). Together, these results suggest that intermodal attention enhances neural processing relatively early in the sensory stream independent from differential effects of spatial and intramodal selective attention.
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Nakata, Hiroki, Tadayoshi Miyamoto, Shigehiko Ogoh, Ryusuke Kakigi, and Manabu Shibasaki. "Effects of acute hypoxia on human cognitive processing: a study using ERPs and SEPs." Journal of Applied Physiology 123, no. 5 (November 1, 2017): 1246–55. http://dx.doi.org/10.1152/japplphysiol.00348.2017.
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Although hypoxia has the potential to impair the cognitive function, the effects of acute hypoxia on the high-order brain function (executive and/or inhibitory processing) and somatosensory ascending processing remain unknown. We tested the hypothesis that acute hypoxia impairs both motor executive and inhibitory processing and somatosensory ascending processing. Fifteen healthy subjects performed two sessions ( sessions 1 and 2), consisting of electroencephalographic event-related potentials with somatosensory Go/No-go paradigms and somatosensory-evoked potentials (SEPs) under two conditions (hypoxia and normoxia) on different days. On 1 day, participants breathed room air in the first and second sessions of the experiment; on the other day, participants breathed room air in the first session, and 12% O2 in the second session. Acute hypoxia reduced the peak amplitudes of Go-P300 and No-go-P300, and delayed the peak latency of Go-P300. However, no significant differences were observed in the peak amplitude or latency of N140, behavioral data, or the amplitudes and latencies of individual SEP components between the two conditions. These results suggest that acute hypoxia impaired neural activity in motor executive and inhibitory processing, and delayed higher cognitive processing for motor execution, whereas neural activity in somatosensory processing was not affected by acute hypoxia. NEW & NOTEWORTHY Hypoxia has the potential to impair the cognitive function, but the effects of acute hypoxia on the cognitive function remain debatable. We investigated the effects of acute hypoxia on human cognitive processing using electroencephalographic event-related potentials and somatosensory-evoked potentials. Acute normobaric hypoxia impaired neural activity in motor executive and inhibitory processing, but no significant differences were observed in neural activity in somatosensory processing.
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Spinelli, Donatella, David C. Burr, and M. Concetta Morrone. "Spatial neglect is associated with increased latencies of visual evoked potentials." Visual Neuroscience 11, no. 5 (September 1994): 909–18. http://dx.doi.org/10.1017/s0952523800003862.
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AbstractWe have recorded steady-state visual evoked potentials (VEPs) from patients with vascular damage to their right brain hemispheres, some suffering from unilateral spatial neglect (n = 9), and some not (n = 7). VEPs were recorded in response to sinusoidal gratings of 0.56 cycle/deg contrast-reversed sinusoidally at temporal frequencies from 4–11 Hz. Stimuli were presented either to the left or to the right visual field, or to both. Confirming previous reports, reliable VEPs were recorded from stimuli in the left contralesional hemifield, of comparable amplitude to those of the ipsilesional hemifield and to those of both hemifields of brain damaged patients without neglect. However, analysis of apparent latency derived from phase data showed that the VEPs from the contralesional hemifield were systematically delayed by 30–40 ms compared with those of the ipsilesional hemifield, and compared with both hemifields of the nonneglect groups. This result suggests changes in neural processing in neglect patients.
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Nakata, Hiroki, Fumino Kobayashi, Justin S. Lawley, Ryusuke Kakigi, and Manabu Shibasaki. "Effects of whole body skin cooling on human cognitive processing: a study using SEPs and ERPs." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 317, no. 3 (September 1, 2019): R432—R441. http://dx.doi.org/10.1152/ajpregu.00087.2019.
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The present study investigated the effect of whole body skin cooling on somatosensory ascending processing by utilizing somatosensory-evoked potentials (SEPs) and motor execution, as well as inhibitory processing by event-related potentials (ERPs). Fourteen healthy participants wearing a water-perfused suit performed two sessions ( sessions 1 and 2) consisting of SEPs and ERPs with somatosensory Go/No-go paradigms under two conditions (cold stress and control) on different days. In session 2, under the cold stress condition, whole body skin cooling was achieved by circulating 20°C water through the suit for 40 min, whereas 34°C water was perfused in the other sessions. The mean skin temperature decreased from 35.0 ± 0.5°C ( session 1) to 30.4 ± 0.9°C ( session 2) during whole body skin cooling, but the internal temperature was maintained. Whole body skin cooling delayed the peak latencies of N20, P25, and P45 components at C4′ of SEPs (all: P < 0.05). Moreover, the peak latencies of P14, N18, and P22 components at Fz of SEPs and the Go-P300 component of ERPs were delayed (all: P < 0.05). In contrast, the peak amplitudes of all individual components of SEPs as well as N140 and P300 of ERPs remained unchanged. These results suggest that passive whole body skin cooling delays neural activities on somatosensory processing and higher cognitive function.
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Nakamura, Kiyohiko. "Neural Processing in the Subsecond Time Range in the Temporal Cortex." Neural Computation 10, no. 3 (April 1, 1998): 567–95. http://dx.doi.org/10.1162/089976698300017674.
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The hypothesis that cortical processing of the millisecond time range is performed by latency competition between the first spikes produced by neuronal populations is analyzed. First, theorems that describe how the mechanism of latency competition works in a model cortex are presented. The model is a sequence of cortical areas, each of which is an array of neuronal populations that laterally inhibit each other. Model neurons are integrate-and-fire neurons. Second, the model is applied to the ventral pathway of the temporal lobe, and neuronal activity of the superior temporal sulcus of the monkey is reproduced with the model pathway. It consists of seven areas: V1, V2/V3, V4, PIT, CIT, AIT, and STPa. Neural activity predicted with the model is compared with empirical data. There are four main results: (1) Neural responses of the area STPa of the model showed the same fast discrimination between stimuli that the corresponding responses of the monkey did: both were significant within 5 ms of the response onset. (2) The hypothesis requires that the response latency of cortical neurons should be shorter for stronger responses. This requirement was verified by both the model simulation and the empirical data. (3) The model reproduced fast discrimination even when spontaneous random firing of 9 Hz was introduced to all the cells. This suggests that the latency competition performed by neuronal populations is robust. (4) After the first few competitions, the mechanism of latency competition always detected the strongest of input activations with different latencies.
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Johnson, Bradley N., Joel D. Mainland, and Noam Sobel. "Rapid Olfactory Processing Implicates Subcortical Control of an Olfactomotor System." Journal of Neurophysiology 90, no. 2 (August 2003): 1084–94. http://dx.doi.org/10.1152/jn.00115.2003.
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Sniffs are modulated in response to odor content. Higher concentrations of odor induce lesser-volume sniffs. This phenomenon implicates a neural feedback mechanism that measures sensory input (odor concentration) and modulates motor output (sniffing) accordingly. Here we used air-dilution olfactometry to probe the time course of this olfactomotor mechanism. A stainless-steel computer-controlled olfactometer, equipped with mass flow controllers, temperature and humidity control, and on-line photo-ionization detection, was coupled to a highly sensitive pneumatotachograph that measured nasal flow. The olfactometer was used to generate four ascending concentrations of the odorants propionic acid and phenethyl alcohol. Sniff volume was inversely related to odor concentration ( P > 0.0001). Sniffs were uniform and concentration independent for the initial 150 ms but acquired a concentration-dependent flowrate as early as 160 ms following sniff onset for propionic acid ( P > 0.05) and 260 ms for phenethyl alcohol ( P > 0.05). Considering that odorant transduction takes around 150 ms and odorant-induced cortical evoked potentials have latencies of around 300 ms, the rapid motor adjustments measured here suggest that olfactomotor sniff feedback control is subcortical and may rely on neural mechanisms similar to those that modulate eye movements to accommodate vision and ear movements to accommodate audition.
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Khullar, Shilpa, S. Aijaz Abbas Rizvi, Ankur Sachdeva, Archana Sood, and Syed Sibte Akbar Abidi. "Variation in interpeak latencies of auditory brainstem responses with age in male adults:An observation." Biomedicine 41, no. 2 (September 7, 2021): 489–92. http://dx.doi.org/10.51248/.v41i2.1064.
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Introduction and Aim: Aging of the auditory pathway is a complex phenomenon consisting of changes in the auditory processing along with a significant elevation of the hearing threshold. The aim of our study was to see the variation in interpeak latencies (IPLs) of Auditory Brainstem Responses (ABRs) with advancing age in males.
Materials and Methods: It was an observational study conducted on 60 Indian male subjects aged between 20 and 80 years divided into three groups on the basis of age: Group 1: 20-40 years, Group 2: 41-60 years and Group 3: 61-80 years. Auditory threshold and ABRs were recorded and analysed for interpeak latencies (IPLs) – I-III,I-V and III-V in msec.The comparison of data between the groups was done using one – way ANOVA and Tukey Kramer multiple comparison test. The results were considered significantly different between the groups when ‘P value’ was ? 0.05.
Results: It was found that there was no significant difference in the auditory threshold and interpeak latencies (IPLs) when comparison was made between the three groups.
Conclusion: Hence we conclude thatage does not have any significant influence on neural conduction time of the auditory pathway which is represented by the IPLs in ABRs.
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Senot, Patrice, Sylvain Baillet, Bernard Renault, and Alain Berthoz. "Cortical Dynamics of Anticipatory Mechanisms in Interception: A Neuromagnetic Study." Journal of Cognitive Neuroscience 20, no. 10 (October 2008): 1827–38. http://dx.doi.org/10.1162/jocn.2008.20129.
Full textAbstract:
Humans demonstrate an amazing ability for intercepting and catching moving targets, most noticeably in fast-speed ball games. However, the few studies exploring the neural bases of interception in humans and the classical studies on visual motion processing and visuomotor interactions have reported rather long latencies of cortical activations that cannot explain the performances observed in most natural interceptive actions. The aim of our experiment was twofold: (1) describe the spatio-temporal unfolding of cortical activations involved in catching a moving target and (2) provide evidence that fast cortical responses can be elicited by a visuomotor task with high temporal constraints and decide if these responses are task or stimulus dependent. Neuromagnetic brain activity was recorded with whole-head coverage while subjects were asked to catch a free-falling ball or simply pay attention to the ball trajectory. A fast, likely stimulus-dependent, propagation of neural activity was observed along the dorsal visual pathway in both tasks. Evaluation of latencies of activations in the main cortical regions involved in the tasks revealed that this entire network of regions was activated within 40 msec. Moreover, comparison of experimental conditions revealed similar patterns of activation except in contralateral sensorimotor regions where common and catch-specific activations were differentiated.
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Stienen, Bernard M. C., Konrad Schindler, and Beatrice de Gelder. "A Computational Feedforward Model Predicts Categorization of Masked Emotional Body Language for Longer, but Not for Shorter, Latencies." Neural Computation 24, no. 7 (July 2012): 1806–21. http://dx.doi.org/10.1162/neco_a_00305.
Full textAbstract:
Given the presence of massive feedback loops in brain networks, it is difficult to disentangle the contribution of feedforward and feedback processing to the recognition of visual stimuli, in this case, of emotional body expressions. The aim of the work presented in this letter is to shed light on how well feedforward processing explains rapid categorization of this important class of stimuli. By means of parametric masking, it may be possible to control the contribution of feedback activity in human participants. A close comparison is presented between human recognition performance and the performance of a computational neural model that exclusively modeled feedforward processing and was engineered to fulfill the computational requirements of recognition. Results show that the longer the stimulus onset asynchrony (SOA), the closer the performance of the human participants was to the values predicted by the model, with an optimum at an SOA of 100 ms. At short SOA latencies, human performance deteriorated, but the categorization of the emotional expressions was still above baseline. The data suggest that, although theoretically, feedback arising from inferotemporal cortex is likely to be blocked when the SOA is 100 ms, human participants still seem to rely on more local visual feedback processing to equal the model's performance.
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Ozmeral, Erol J., David A. Eddins, and Ann C. Eddins. "Reduced temporal processing in older, normal-hearing listeners evident from electrophysiological responses to shifts in interaural time difference." Journal of Neurophysiology 116, no. 6 (December 1, 2016): 2720–29. http://dx.doi.org/10.1152/jn.00560.2016.
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Previous electrophysiological studies of interaural time difference (ITD) processing have demonstrated that ITDs are represented by a nontopographic population rate code. Rather than narrow tuning to ITDs, neural channels have broad tuning to ITDs in either the left or right auditory hemifield, and the relative activity between the channels determines the perceived lateralization of the sound. With advancing age, spatial perception weakens and poor temporal processing contributes to declining spatial acuity. At present, it is unclear whether age-related temporal processing deficits are due to poor inhibitory controls in the auditory system or degraded neural synchrony at the periphery. Cortical processing of spatial cues based on a hemifield code are susceptible to potential age-related physiological changes. We consider two distinct predictions of age-related changes to ITD sensitivity: declines in inhibitory mechanisms would lead to increased excitation and medial shifts to rate-azimuth functions, whereas a general reduction in neural synchrony would lead to reduced excitation and shallower slopes in the rate-azimuth function. The current study tested these possibilities by measuring an evoked response to ITD shifts in a narrow-band noise. Results were more in line with the latter outcome, both from measured latencies and amplitudes of the global field potentials and source-localized waveforms in the left and right auditory cortices. The measured responses for older listeners also tended to have reduced asymmetric distribution of activity in response to ITD shifts, which is consistent with other sensory and cognitive processing models of aging.
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Si, Xiaopeng, Wenjing Zhou, and Bo Hong. "Cooperative cortical network for categorical processing of Chinese lexical tone." Proceedings of the National Academy of Sciences 114, no. 46 (October 30, 2017): 12303–8. http://dx.doi.org/10.1073/pnas.1710752114.
Full textAbstract:
In tonal languages such as Chinese, lexical tone with varying pitch contours serves as a key feature to provide contrast in word meaning. Similar to phoneme processing, behavioral studies have suggested that Chinese tone is categorically perceived. However, its underlying neural mechanism remains poorly understood. By conducting cortical surface recordings in surgical patients, we revealed a cooperative cortical network along with its dynamics responsible for this categorical perception. Based on an oddball paradigm, we found amplified neural dissimilarity between cross-category tone pairs, rather than between within-category tone pairs, over cortical sites covering both the ventral and dorsal streams of speech processing. The bilateral superior temporal gyrus (STG) and the middle temporal gyrus (MTG) exhibited increased response latencies and enlarged neural dissimilarity, suggesting a ventral hierarchy that gradually differentiates the acoustic features of lexical tones. In addition, the bilateral motor cortices were also found to be involved in categorical processing, interacting with both the STG and the MTG and exhibiting a response latency in between. Moreover, the motor cortex received enhanced Granger causal influence from the semantic hub, the anterior temporal lobe, in the right hemisphere. These unique data suggest that there exists a distributed cooperative cortical network supporting the categorical processing of lexical tone in tonal language speakers, not only encompassing a bilateral temporal hierarchy that is shared by categorical processing of phonemes but also involving intensive speech–motor interactions over the right hemisphere, which might be the unique machinery responsible for the reliable discrimination of tone identities.
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Garner, Kelly G., Natasha Matthews, Roger W. Remington, and Paul E. Dux. "Transferability of Training Benefits Differs across Neural Events: Evidence from ERPs." Journal of Cognitive Neuroscience 27, no. 10 (October 2015): 2079–94. http://dx.doi.org/10.1162/jocn_a_00833.
Full textAbstract:
Humans can show striking capacity limitations in sensorimotor processing. Fortunately, these limitations can be attenuated with training. However, less fortunately, training benefits often remain limited to trained tasks. Recent behavioral observations suggest that the extent to which training transfers may depend on the specific stage of information processing that is being executed. Training benefits for a task that taps the consolidation of sensory information (sensory encoding) transfer to new stimulus–response mappings, whereas benefits for selecting an appropriate action (decision-making/response selection) remain specific to the trained mappings. Therefore, training may have dissociable influences on the neural events underlying subsequent sensorimotor processing stages. Here, we used EEG to investigate this possibility. In a pretraining baseline session, participants completed two four-alternative-choice response time tasks, presented both as a single task and as part of a dual task (with another task). The training group completed a further 3,000 training trials on one of the four-alternative-choice tasks. Hence, one task became trained, whereas the other remained untrained. At test, a negative-going component that is sensitive to sensory-encoding demands (N2) showed increased amplitudes and reduced latencies for trained and untrained mappings relative to a no-train control group. In contrast, the onset of the stimulus-locked lateralized readiness potential, a component that reflects the activation of motor plans, was reduced only for tasks that employed trained stimulus–response mappings, relative to untrained stimulus–response mappings and controls. Collectively, these results show that training benefits are dissociable for the brain events that reflect distinct sensorimotor processing stages.
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Chen, Chenyi, Chin-Yau Chen, Chih-Yung Yang, Chi-Hung Lin, and Yawei Cheng. "Testosterone modulates preattentive sensory processing and involuntary attention switches to emotional voices." Journal of Neurophysiology 113, no. 6 (March 15, 2015): 1842–49. http://dx.doi.org/10.1152/jn.00587.2014.
Full textAbstract:
Testosterone is capable of altering facial threat processing. Voices, similar to faces, convey social information. We hypothesized that administering a single dose of testosterone would change voice perception in humans. In a placebo-controlled, randomly assigned, double-blind crossover design, we administered a single dose of testosterone or placebo to 18 healthy female volunteers and used a passive auditory oddball paradigm. The mismatch negativity (MMN) and P3a in responses to fearfully, happily, and neutrally spoken syllables dada and acoustically matched nonvocal sounds were analyzed, indicating preattentive sensory processing and involuntary attention switches. Results showed that testosterone administration had a trend to shorten the peak latencies of happy MMN and significantly enhanced the amplitudes of happy and fearful P3a, whereas the happy- and fearful-derived nonvocal MMN and P3a remained unaffected. These findings demonstrated acute effect of testosterone on the neural dynamics of voice perception. Administering a single dose of testosterone modulates preattentive sensory processing and involuntary attention switches in response to emotional voices.
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Lovick, T. A., and A. J. Devall. "Progesterone Withdrawal-Evoked Plasticity of Neural Function in the Female Periaqueductal Grey Matter." Neural Plasticity 2009 (2009): 1–8. http://dx.doi.org/10.1155/2009/730902.
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Cyclical changes in production of neuroactive steroids during the oestrous cycle induce significant changes inGABAAreceptor expression in female rats. In the periaqueductal grey (PAG) matter, upregulation ofα4β1δGABAAreceptors occurs as progesterone levels fall during late dioestrus (LD) or during withdrawal from an exogenous progesterone dosing regime. The new receptors are likely to be extrasynaptically located on the GABAergic interneurone population and to mediate tonic currents. Electrophysiological studies showed that whenα4β1δGABAAreceptor expression was increased, the excitability of the output neurones in the PAG increased, due to a decrease in the level of ongoing inhibitory tone from the GABAergic interneurones. The functional consequences in terms of nociceptive processing were investigated in conscious rats. Baseline tail flick latencies were similar in all rats. However, acute exposure to mild vibration stress evoked hyperalgesia in rats in LD and after progesterone withdrawal, in line with the upregulation ofα4β1δGABAAreceptor expression.
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Jia, Huibin, Huayun Li, and Dongchuan Yu. "The relationship between ERP components and EEG spatial complexity in a visual Go/Nogo task." Journal of Neurophysiology 117, no. 1 (January 1, 2017): 275–83. http://dx.doi.org/10.1152/jn.00363.2016.
Full textAbstract:
The ERP components and variations of spatial complexity or functional connectivity are two distinct dimensions of neurophysiological events in the visual Go/Nogo task. Extensive studies have been conducted on these two distinct dimensions; however, no study has investigated whether these two neurophysiological events are linked to each other in the visual Go/Nogo task. The relationship between spatial complexity of electroencephalographic (EEG) data, quantified by the measure omega complexity, and event-related potential (ERP) components in a visual Go/Nogo task was studied. We found that with the increase of spatial complexity level, the latencies of N1 and N2 component were shortened and the amplitudes of N1, N2, and P3 components were decreased. The anterior Go/Nogo N2 effect and the Go/Nogo P3 effect were also found to be decreased with the increase of EEG spatial complexity. In addition, the reaction times in high spatial complexity trials were significantly shorter than those of medium and low spatial complexity trials when the time interval used to estimate the EEG spatial complexity was extended to 0∼1,000 ms after stimulus onset. These results suggest that high spatial complexity may be associated with faster cognitive processing and smaller postsynaptic potentials that occur simultaneously in large numbers of cortical pyramidal cells of certain brain regions. The EEG spatial complexity is closely related with demands of certain cognitive processes and the neural processing efficiency of human brain. NEW & NOTEWORTHY The reaction times, the latencies/amplitudes of event-related potential (ERP) components, the Go/Nogo N2 effect, and the Go/Nogo P3 effect are linked to the electroencephalographic (EEG) spatial complexity level. The EEG spatial complexity is closely related to demands of certain cognitive processes and could reflect the neural processing efficiency of human brain. Obtaining the single-trial ERP features through single-trial spatial complexity may be a more efficient approach than traditional methods.
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Harris, Kelly C., Kenneth I. Vaden, Carolyn M. McClaskey, James W. Dias, and Judy R. Dubno. "Complementary metrics of human auditory nerve function derived from compound action potentials." Journal of Neurophysiology 119, no. 3 (March 1, 2018): 1019–28. http://dx.doi.org/10.1152/jn.00638.2017.
Full textAbstract:
Declines in auditory nerve (AN) function contribute to suprathreshold auditory processing and communication deficits in individuals with normal hearing, hearing loss, hyperacusis, and tinnitus. Procedures to characterize AN loss or dysfunction in humans are limited. We report several novel complementary metrics using the compound action potential (CAP), a direct measure of summated AN activity. Together, these metrics may be used to characterize AN function noninvasively in humans. We examined how these metrics change with stimulus intensity and interpreted these changes within a framework of known physiological properties of the basilar membrane and AN. Our results reveal how neural synchrony and the recruitment of AN fibers with longer first-spike latencies likely contribute to the CAP, affect auditory processing, and differ with noise exposure history in younger adults with normal pure-tone thresholds. Moving forward, this new battery of metrics provides a crucial step toward new diagnostics of AN function in humans. NEW & NOTEWORTHY Loss or inactivity of auditory nerve (AN) fibers is thought to contribute to suprathreshold auditory processing deficits, but evidence-based methods to assess these effects are not available. We describe several novel metrics that together may be used to quantify neural synchrony and characterize AN function in humans.
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de Boer, Jessica, and Katrin Krumbholz. "Auditory Attention Causes Gain Enhancement and Frequency Sharpening at Successive Stages of Cortical Processing—Evidence from Human Electroencephalography." Journal of Cognitive Neuroscience 30, no. 6 (June 2018): 785–98. http://dx.doi.org/10.1162/jocn_a_01245.
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Previous findings have suggested that auditory attention causes not only enhancement in neural processing gain, but also sharpening in neural frequency tuning in human auditory cortex. The current study was aimed to reexamine these findings. Specifically, we aimed to investigate whether attentional gain enhancement and frequency sharpening emerge at the same or different processing levels and whether they represent independent or cooperative effects. For that, we examined the pattern of attentional modulation effects on early, sensory-driven cortical auditory-evoked potentials occurring at different latencies. Attention was manipulated using a dichotic listening task and was thus not selectively directed to specific frequency values. Possible attention-related changes in frequency tuning selectivity were measured with an adaptation paradigm. Our results show marked disparities in attention effects between the earlier N1 deflection and the subsequent P2 deflection, with the N1 showing a strong gain enhancement effect, but no sharpening, and the P2 showing clear evidence of sharpening, but no independent gain effect. They suggest that gain enhancement and frequency sharpening represent successive stages of a cooperative attentional modulation mechanism that increases the representational bandwidth of attended versus unattended sounds.
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Lyons-Warren, Ariel M., Tsunehiko Kohashi, Steven Mennerick, and Bruce A. Carlson. "Detection of submillisecond spike timing differences based on delay-line anticoincidence detection." Journal of Neurophysiology 110, no. 10 (November 15, 2013): 2295–311. http://dx.doi.org/10.1152/jn.00444.2013.
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Detection of submillisecond interaural timing differences is the basis for sound localization in reptiles, birds, and mammals. Although comparative studies reveal that different neural circuits underlie this ability, they also highlight common solutions to an inherent challenge: processing information on timescales shorter than an action potential. Discrimination of small timing differences is also important for species recognition during communication among mormyrid electric fishes. These fishes generate a species-specific electric organ discharge (EOD) that is encoded into submillisecond-to-millisecond timing differences between receptors. Small, adendritic neurons (small cells) in the midbrain are thought to analyze EOD waveform by comparing these differences in spike timing, but direct recordings from small cells have been technically challenging. In the present study we use a fluorescent labeling technique to obtain visually guided extracellular recordings from individual small cell axons. We demonstrate that small cells receive 1–2 excitatory inputs from 1 or more receptive fields with latencies that vary by over 10 ms. This wide range of excitatory latencies is likely due to axonal delay lines, as suggested by a previous anatomic study. We also show that inhibition of small cells from a calyx synapse shapes stimulus responses in two ways: through tonic inhibition that reduces spontaneous activity and through precisely timed, stimulus-driven, feed-forward inhibition. Our results reveal a novel delay-line anticoincidence detection mechanism for processing submillisecond timing differences, in which excitatory delay lines and precisely timed inhibition convert a temporal code into a population code.
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Park, Joonkoo, Crystal Chiang, Elizabeth M. Brannon, and Marty G. Woldorff. "Experience-dependent Hemispheric Specialization of Letters and Numbers Is Revealed in Early Visual Processing." Journal of Cognitive Neuroscience 26, no. 10 (October 2014): 2239–49. http://dx.doi.org/10.1162/jocn_a_00621.
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Recent fMRI research has demonstrated that letters and numbers are preferentially processed in distinct regions and hemispheres in the visual cortex. In particular, the left visual cortex preferentially processes letters compared with numbers, whereas the right visual cortex preferentially processes numbers compared with letters. Because letters and numbers are cultural inventions and are otherwise physically arbitrary, such a double dissociation is strong evidence for experiential effects on neural architecture. Here, we use the high temporal resolution of ERPs to investigate the temporal dynamics of the neural dissociation between letters and numbers. We show that the divergence between ERP traces to letters and numbers emerges very early in processing. Letters evoked greater N1 waves (latencies 140–170 msec) than did numbers over left occipital channels, whereas numbers evoked greater N1s than letters over the right, suggesting letters and numbers are preferentially processed in opposite hemispheres early in visual encoding. Moreover, strings of letters, but not single letters, elicited greater P2 ERP waves (starting around 250 msec) than numbers did over the left hemisphere, suggesting that the visual cortex is tuned to selectively process combinations of letters, but not numbers, further along in the visual processing stream. Additionally, the processing of both of these culturally defined stimulus types differentiated from similar but unfamiliar visual stimulus forms (false fonts) even earlier in the processing stream (the P1 at 100 msec). These findings imply major cortical specialization processes within the visual system driven by experience with reading and mathematics.
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Tahaei, Ali Akbar, Hassan Ashayeri, Akram Pourbakht, and Mohammad Kamali. "Speech Evoked Auditory Brainstem Response in Stuttering." Scientifica 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/328646.
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Auditory processing deficits have been hypothesized as an underlying mechanism for stuttering. Previous studies have demonstrated abnormal responses in subjects with persistent developmental stuttering (PDS) at the higher level of the central auditory system using speech stimuli. Recently, the potential usefulness of speech evoked auditory brainstem responses in central auditory processing disorders has been emphasized. The current study used the speech evoked ABR to investigate the hypothesis that subjects with PDS have specific auditory perceptual dysfunction.Objectives. To determine whether brainstem responses to speech stimuli differ between PDS subjects and normal fluent speakers.Methods. Twenty-five subjects with PDS participated in this study. The speech-ABRs were elicited by the 5-formant synthesized syllable/da/, with duration of 40 ms.Results. There were significant group differences for the onset and offset transient peaks. Subjects with PDS had longer latencies for the onset and offset peaks relative to the control group.Conclusions. Subjects with PDS showed a deficient neural timing in the early stages of the auditory pathway consistent with temporal processing deficits and their abnormal timing may underlie to their disfluency.
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Lee, Joonyeol, Timothy R. Darlington, and Stephen G. Lisberger. "The Neural Basis for Response Latency in a Sensory-Motor Behavior." Cerebral Cortex 30, no. 5 (December 11, 2019): 3055–73. http://dx.doi.org/10.1093/cercor/bhz294.
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Abstract We seek a neural circuit explanation for sensory-motor reaction times. In the smooth eye movement region of the frontal eye fields (FEFSEM), the latencies of pairs of neurons show trial-by-trial correlations that cause trial-by-trial correlations in neural and behavioral latency. These correlations can account for two-third of the observed variation in behavioral latency. The amplitude of preparatory activity also could contribute, but the responses of many FEFSEM neurons fail to support predictions of the traditional “ramp-to-threshold” model. As a correlate of neural processing that determines reaction time, the local field potential in FEFSEM includes a brief wave in the 5–15-Hz frequency range that precedes pursuit initiation and whose phase is correlated with the latency of pursuit in individual trials. We suggest that the latency of the incoming visual motion signals combines with the state of preparatory activity to determine the latency of the transient response that controls eye movement. Impact statement The motor cortex for smooth pursuit eye movements contributes to sensory-motor reaction time through the amplitude of preparatory activity and the latency of transient, visually driven responses.
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Nieder, Andreas, and Earl K. Miller. "Analog Numerical Representations in Rhesus Monkeys: Evidence for Parallel Processing." Journal of Cognitive Neuroscience 16, no. 5 (June 2004): 889–901. http://dx.doi.org/10.1162/089892904970807.
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Monkeys have been introduced as model organisms to study neural correlates of numerical competence, but many of the behavioral characteristics of numerical judgments remain speculative. Thus, we analyzed the behavioral performance of two rhesus monkeys judging the numerosities 1 to 7 during a delayed match-to-sample task. The monkeys showed similar discrimination performance irrespective of the exact physical appearance of the stimuli, confirming that performance was based on numerical information. Performance declined smoothly with larger numerosities, and reached discrimination threshold at numerosity “4.” The nonverbal numerical representations in monkeys were based on analog magnitudes, object tracking process (“subitizing”) could not account for the findings because the continuum of small and large numbers shows a clear Weber fraction signature. The lack of additional scanning eye movements with increasing set sizes, together with indistinguishable neuronal response latencies for neurons with different preferred numerosities, argues for parallel encoding of numerical information. The slight but significant increase in reaction time with increasing numerosities can be explained by task difficulty and consequently time-consuming decision processes. The behavioral results are compared to single-cell recordings from the prefrontal cortex in the same subjects. Models for numerosity discrimination that may account for these results are discussed.
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Galazyuk, Alexander V., Wenyu Lin, Daniel Llano, and Albert S. Feng. "Leading Inhibition to Neural Oscillation Is Important for Time-Domain Processing in the Auditory Midbrain." Journal of Neurophysiology 94, no. 1 (July 2005): 314–26. http://dx.doi.org/10.1152/jn.00056.2005.
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A number of central auditory neurons exhibit paradoxical latency shift (PLS), a response characterized by longer response latencies at higher sound levels. PLS neurons are known to play a role in target ranging for echolocating bats that emit frequency-modulated sounds. We recently reported that early inhibition of unit’s oscillatory discharges is critical for PLS in the inferior colliculus (IC) of little brown bats. The goal of this study was to determine in echolocating bats and in nonecholocating animals (frogs): 1) the detailed characteristics of PLS and whether PLS was dependent on sound level, frequency, and duration; 2) the time course of inhibition underlying PLS using a paired-pulse paradigm. We found that 22% of IC neurons in bats and 15% in frogs exhibited periodic discharge patterns in response to tone pulses at high sound levels. The firing periodicity was unit specific and independent of sound level and duration. Other IC neurons (28% in bats; 14% in frogs) exhibited PLS. These PLS neurons shared several response characteristics: 1) PLS was largely independent of sound frequency and 2) the magnitude of shift in first-spike latency was either duration dependent or duration tolerant. For PLS neurons, application of bicuculline abolished PLS and unmasked the unit’s periodical firing pattern that served as the building block for PLS. In response to paired sound pulses, PLS neurons exhibited delay-dependent response suppression, confirming that high-threshold leading inhibition was responsible for PLS. Results also revealed the timing of excitatory and inhibitory inputs underlying PLS and its role in time-domain processing.
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Yan Shan, Tai, Faruque Reza, Tahamina Begum, and Nasir Yusoff. "Neural Processing of Other-Race Faces as a Function of Racial Familiarity: A P300 Study." International Journal of Engineering & Technology 7, no. 3.22 (August 8, 2018): 21. http://dx.doi.org/10.14419/ijet.v7i3.22.17116.
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Background: The other-race categorisation advantage (ORCA) is a well-established phenomenon, whereby other-race faces are categorised faster than own race faces. Objectives: This study investigated whether extraverts would demonstrate an ORCA-like effect toward unfamiliar other-race faces and familiar other-race faces in a modified oddball and choice reaction paradigm. Methods: This event-related potential (ERP) study employed a repeated measures experimental design with one independent variable (racial familiarity) and three levels (familiar other-race/Malay faces, unfamiliar other-race/African faces, control group/furniture photos). In the oddball task, African faces and Malay faces were the target stimuli and furniture photos were the standard stimuli. Electroencephalography data (EEG) was collected during the oddball task, from which ERP components were derived. Results: The reaction time (RT) for African and Malay faces were not significantly different. Significant effect of racial familiarity on P300 latencies at all electrode sites was not observed. However, there was a significant effect of racial familiarity on P300 amplitudes at midline electrodes (Cz). It was also observed that the P300 amplitude was larger for African faces than Malay faces at midline electrodes (Cz). Conclusion: An ORCA-like effect was not found in categorisation tasks involving faces from a familiar and an unfamiliar other-race, but a larger P300 amplitude was evoked by African faces. This dissociation between RT and P300 amplitude provided important theoretical implications with regard to models associated with ORCA. Specifically, the current findings lent support to the social cognition model and the Categorisation-Individuation Model (CIM).
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Pavlova, Marina, Christel Bidet-Ildei, Alexander N. Sokolov, Christoph Braun, and Ingeborg Krägeloh-Mann. "Neuromagnetic Response to Body Motion and Brain Connectivity." Journal of Cognitive Neuroscience 21, no. 5 (May 2009): 837–46. http://dx.doi.org/10.1162/jocn.2009.21050.
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Visual detection of body motion is of immense importance for daily-life activities and social nonverbal interaction. Although neurobiological mechanisms underlying visual processing of human locomotion are being explored extensively by brain imaging, the role of structural brain connectivity is not well understood. Here we investigate cortical evoked neuromagnetic response to point-light body motion in healthy adolescents and in patients with early periventricular lesions, periventricular leukomalacia (PVL), that disrupt brain connectivity. In a simultaneous masking paradigm, participants detected the presence of a point-light walker embedded in a few sets of spatially scrambled dots on the joints of a walker. The visual sensitivity to camouflaged human locomotion was lower in PVL patients. In accord with behavioral data, root-mean-square (RMS) amplitude of neuromagnetic trace in response to human locomotion was lower in PVL patients at latencies of 180–244 msec over the right temporal cortex. In this time window, the visual sensitivity to body motion in controls, but not in PVL patients, was inversely linked to the right temporal activation. At later latencies of 276–340 msec, we found reduction in RMS amplitude in PVL patients for body motion stimuli over the right frontal cortex. The findings indicate that disturbances in brain connectivity with the right temporal cortex, a key node of the social brain, and with the right frontal cortex lead to disintegration of the neural network engaged in visual processing of body motion. We suspect that reduced cortical response to body motion over the right temporal and frontal cortices might underlie deficits in visual social cognition.
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Mitterschiffthaler, M. T., S. C. R. Williams, N. D. Walsh, A. J. Cleare, C. Donaldson, J. Scott, and C. H. Y. Fu. "Neural basis of the emotional Stroop interference effect in major depression." Psychological Medicine 38, no. 2 (September 10, 2007): 247–56. http://dx.doi.org/10.1017/s0033291707001523.
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BackgroundA mood-congruent sensitivity towards negative stimuli has been associated with development and maintenance of major depressive disorder (MDD). The emotional Stroop task assesses interference effects arising from the conflict of emotional expressions consistent with disorder-specific self-schemata and cognitive colour-naming instructions. Functional neuroimaging studies of the emotional Stroop effect advocate a critical involvement of the anterior cingulate cortex (ACC) during these processes.MethodSubjects were 17 medication-free individuals with unipolar MDD in an acute depressive episode (mean age 39 years), and 17 age-, gender- and IQ-matched healthy volunteers. In an emotional Stroop task, sad and neutral words were presented in various colours, and subjects were required to name the colour of words whilst undergoing functional magnetic resonance imaging (fMRI). Overt verbal responses were acquired with a clustered fMRI acquisition sequence.ResultsIndividuals with depression showed greater increases in response time from neutral to sad words relative to controls. fMRI data showed a significant engagement of left rostral ACC (BA 32) and right precuneus during sad words in patients relative to controls. Additionally, rostral ACC activation was positively correlated with latencies of negative words in MDD patients. Healthy controls did not have any regions of increased activation compared to MDD patients.ConclusionsThese findings provide evidence for a behavioural and neural emotional Stroop effect in MDD and highlight the importance of the ACC during monitoring of conflicting cognitive processes and mood-congruent processing in depression.
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Fardo, Francesca, Mikkel C. Vinding, Micah Allen, Troels Staehelin Jensen, and Nanna Brix Finnerup. "Delta and gamma oscillations in operculo-insular cortex underlie innocuous cold thermosensation." Journal of Neurophysiology 117, no. 5 (May 1, 2017): 1959–68. http://dx.doi.org/10.1152/jn.00843.2016.
Full textAbstract:
Cold-sensitive and nociceptive neural pathways interact to shape the quality and intensity of thermal and pain perception. Yet the central processing of cold thermosensation in the human brain has not been extensively studied. Here, we used magnetoencephalography and EEG in healthy volunteers to investigate the time course (evoked fields and potentials) and oscillatory activity associated with the perception of cold temperature changes. Nonnoxious cold stimuli consisting of Δ3°C and Δ5°C decrements from an adapting temperature of 35°C were delivered on the dorsum of the left hand via a contact thermode. Cold-evoked fields peaked at around 240 and 500 ms, at peak latencies similar to the N1 and P2 cold-evoked potentials. Importantly, cold-related changes in oscillatory power indicated that innocuous thermosensation is mediated by oscillatory activity in the range of delta (1–4 Hz) and gamma (55–90 Hz) rhythms, originating in operculo-insular cortical regions. We suggest that delta rhythms coordinate functional integration between operculo-insular and frontoparietal regions, while gamma rhythms reflect local sensory processing in operculo-insular areas. NEW & NOTEWORTHY Using magnetoencephalography, we identified spatiotemporal features of central cold processing, with respect to the time course, oscillatory profile, and neural generators of cold-evoked responses in healthy human volunteers. Cold thermosensation was associated with low- and high-frequency oscillatory rhythms, both originating in operculo-insular regions. These results support further investigations of central cold processing using magnetoencephalography or EEG and the clinical utility of cold-evoked potentials for neurophysiological assessment of cold-related small-fiber function and damage.
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Omidvar, Shaghayegh, Fauve Duquette-Laplante, Caryn Bursch, Benoît Jutras, and Amineh Koravand. "Assessing Auditory Processing in Children with Listening Difficulties: A Pilot Study." Journal of Clinical Medicine 12, no. 3 (January 23, 2023): 897. http://dx.doi.org/10.3390/jcm12030897.
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Background: Auditory processing disorders (APD) may be one of the problems experienced by children with listening difficulties (LiD). The combination of auditory behavioural and electrophysiological tests could help to provide a better understanding of the abilities/disabilities of children with LiD. The current study aimed to quantify the auditory processing abilities and function in children with LiD. Methods: Twenty children, ten with LiD (age = 8.46; SD = 1.39) and ten typically developing (TD) (age = 9.45; SD = 1.57) participated in this study. All children were evaluated with auditory processing tests as well as with attention and phonemic synthesis tasks. Electrophysiological measures were also conducted with click and speech auditory brainstem responses (ABR). Results: Children with LiD performed significantly worse than TD children for most behavioural tasks, indicating shortcomings in functional auditory processing. Moreover, the click-ABR wave I amplitude was smaller, and the speech-ABR waves D and E latencies were longer for the LiD children compared to the results of TD children. No significant difference was found when evaluating neural correlates between groups. Conclusions: Combining behavioural testing with click-ABR and speech-ABR can highlight functional and neurophysiological deficiencies in children with learning and listening issues, especially at the brainstem level.
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Taillez, Tobias de, Florian Denk, Bojana Mirkovic, Birger Kollmeier, and Bernd T. Meyer. "Modeling Nonlinear Transfer Functions from Speech Envelopes to Encephalography with Neural Networks." International Journal of Psychological Studies 11, no. 4 (August 13, 2019): 1. http://dx.doi.org/10.5539/ijps.v11n4p1.
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Diferent linear models have been proposed to establish a link between an auditory stimulus and the neurophysiological response obtained through electroencephalography (EEG). We investigate if non-linear mappings can be modeled with deep neural networks trained on continuous speech envelopes and EEG data obtained in an auditory attention two-speaker scenario. An artificial neural network was trained to predict the EEG response related to the attended and unattended speech envelopes. After training, the properties of the DNN-based model are analyzed by measuring the transfer function between input envelopes and predicted EEG signals by using click-like stimuli and frequency sweeps as input patterns. Using sweep responses allows to separate the linear and nonlinear response components also with respect to attention. The responses from the model trained on normal speech resemble event-related potentials despite the fact that the DNN was not trained to reproduce such patterns. These responses are modulated by attention, since we obtain significantly lower amplitudes at latencies of 110 ms, 170 ms and 300 ms after stimulus presentation for unattended processing in contrast to the attended. The comparison of linear and nonlinear components indicates that the largest contribution arises from linear processing (75%), while the remaining 25% are attributed to nonlinear processes in the model. Further, a spectral analysis showed a stronger 5 Hz component in modeled EEG for attended in contrast to unattended predictions. The results indicate that the artificial neural network produces responses consistent with recent findings and presents a new approach for quantifying the model properties.
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Akdeniz, Gülsüm, Sadiye Gumusyayla, Gonul Vural, Hesna Bektas, and Orhan Deniz. "Changes in face and face pareidolia processing in patients with migraine: an ERP study." Journal of Neurophysiology 123, no. 3 (March 1, 2020): 876–84. http://dx.doi.org/10.1152/jn.00549.2019.
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Migraine is a multifactorial brain disorder characterized by recurrent disabling headache attacks. One of the possible mechanisms in the pathogenesis of migraine may be a decrease in inhibitory cortical stimuli in the primary visual cortex attributable to cortical hyperexcitability. The aim of this study was to investigate the neural correlates underlying face and face pareidolia processing in terms of the event-related potential (ERP) components, N170, vertex positive potential (VPP), and N250, in patients with migraine. In total, 40 patients with migraine without aura, 23 patients with migraine and aura, and 30 healthy controls were enrolled. We recorded ERPs during the presentation of face and face pareidolia images. N170, VPP, and N250 mean amplitudes and latencies were examined. N170 was significantly greater in patients with migraine with aura than in healthy controls. VPP amplitude was significantly greater in patients with migraine without aura than in healthy controls. The face stimuli evoked significantly earlier VPP responses to faces (168.7 ms, SE = 1.46) than pareidolias (173.4 ms, SE = 1.41) in patients with migraine with aura. We did not find a significant difference between N250 amplitude for face and face pareidolia processing. A significant difference was observed between the groups for pareidolia in terms of N170 [F(2,86) = 14,75, P < 0.001] and VPP [F(2,86) = 16.43, P < 0.001] amplitudes. Early ERPs are a valuable tool to study the neural processing of face processing in patients with migraine to demonstrate visual cortical hyperexcitability. NEW & NOTEWORTHY Event-related potentials (ERPs) are important for understanding face and face pareidolia processing in patients with migraine. N170, vertex positive potential (VPP), and N250 ERPs were investigated. N170 was revealed as a potential component of cortical excitability for face and face pareidolia processing in patients with migraine.
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Roque, Lindsey, Casey Gaskins, Sandra Gordon-Salant, Matthew J. Goupell, and Samira Anderson. "Age Effects on Neural Representation and Perception of Silence Duration Cues in Speech." Journal of Speech, Language, and Hearing Research 62, no. 4S (April 26, 2019): 1099–116. http://dx.doi.org/10.1044/2018_jslhr-h-ascc7-18-0076.
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Purpose Degraded temporal processing associated with aging may be a contributing factor to older adults' hearing difficulties, especially in adverse listening environments. This degraded processing may affect the ability to distinguish between words based on temporal duration cues. The current study investigates the effects of aging and hearing loss on cortical and subcortical representation of temporal speech components and on the perception of silent interval duration cues in speech. Method Identification functions for the words DISH and DITCH were obtained on a 7-step continuum of silence duration (0–60 ms) prior to the final fricative in participants who are younger with normal hearing (YNH), older with normal hearing (ONH), and older with hearing impairment (OHI). Frequency-following responses and cortical auditory-evoked potentials were recorded to the 2 end points of the continuum. Auditory brainstem responses to clicks were obtained to verify neural integrity and to compare group differences in auditory nerve function. A multiple linear regression analysis was conducted to determine the peripheral or central factors that contributed to perceptual performance. Results ONH and OHI participants required longer silence durations to identify DITCH than did YNH participants. Frequency-following responses showed reduced phase locking and poorer morphology, and cortical auditory-evoked potentials showed prolonged latencies in ONH and OHI participants compared with YNH participants. No group differences were noted for auditory brainstem response Wave I amplitude or Wave V/I ratio. After accounting for the possible effects of hearing loss, linear regression analysis revealed that both midbrain and cortical processing contributed to the variance in the DISH–DITCH perceptual identification functions. Conclusions These results suggest that age-related deficits in the ability to encode silence duration cues may be a contributing factor in degraded speech perception. In particular, degraded response morphology relates to performance on perceptual tasks based on silence duration contrasts between words.
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Disbrow, Elizabeth, Tim Roberts, David Poeppel, and Leah Krubitzer. "Evidence for Interhemispheric Processing of Inputs From the Hands in Human S2 and PV." Journal of Neurophysiology 85, no. 5 (May 1, 2001): 2236–44. http://dx.doi.org/10.1152/jn.2001.85.5.2236.
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In the present investigation, we identified cortical areas involved in the integration of bimanual inputs in human somatosensory cortex. Using functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG), we compared the responses to unilateral versus bilateral stimulation in anterior parietal cortex and areas in the Sylvian fissure of the contralateral hemisphere. The extent of fMRI activation on the upper bank of the Sylvian fissure, in the second somatosensory (S2) and the parietal ventral (PV) areas, was significantly larger for bilateral stimulation than for unilateral stimulation. Using MEG, we were able to describe the latency of response in S1 and S2/PV to unilateral and bilateral stimulation. The MEG response had three components under both stimulus conditions. An early peak in S1 at 40 ms, a middle peak in S2/PV at 80–160 ms, and three late peaks in S2/PV at 250–420 ms. There was an increase in magnetic field strength in S2/PV to bilateral stimulation at 300–400 ms post stimulus. The fMRI results indicate that, as in monkeys, S2/PV receives inputs from both the contralateral and ipsilateral hand. The MEG data suggest that information is processed serially from S1 to S2. The very late response in S2/PV indicates that extensive intrahemispheric processing occurs before information is transferred to the opposite hemisphere. The neural substrate for the increased activation and field strength at long latencies during bilateral stimulation can be accounted for in three ways. Under bilateral stimulus conditions, more neurons may be active, neuronal firing rate may increase, and/or neural activity may be more synchronous.
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Rueschemeyer, Shirley-Ann, Oliver Lindemann, Daan van Rooij, Wessel van Dam, and Harold Bekkering. "Effects of Intentional Motor Actions on Embodied Language Processing." Experimental Psychology 57, no. 4 (December 1, 2010): 260–66. http://dx.doi.org/10.1027/1618-3169/a000031.
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Embodied theories of language processing suggest that this motor simulation is an automatic and necessary component of meaning representation. If this is the case, then language and action systems should be mutually dependent (i.e., motor activity should selectively modulate processing of words with an action-semantic component). In this paper, we investigate in two experiments whether evidence for mutual dependence can be found using a motor priming paradigm. Specifically, participants performed either an intentional or a passive motor task while processing words denoting manipulable and nonmanipulable objects. The performance rates (Experiment 1) and response latencies (Experiment 2) in a lexical-decision task reveal that participants performing an intentional action were positively affected in the processing of words denoting manipulable objects as compared to nonmanipulable objects. This was not the case if participants performed a secondary passive motor action (Experiment 1) or did not perform a secondary motor task (Experiment 2). The results go beyond previous research showing that language processes involve motor systems to demonstrate that the execution of motor actions has a selective effect on the semantic processing of words. We suggest that intentional actions activate specific parts of the neural motor system, which are also engaged for lexical-semantic processing of action-related words and discuss the beneficial versus inhibitory nature of this relationship. The results provide new insights into the embodiment of language and the bidirectionality of effects between language and action processing.
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Henkin, Yael, Yifat Yaar-Soffer, Lihi Givon, and Minka Hildesheimer. "Hearing with Two Ears: Evidence for Cortical Binaural Interaction during Auditory Processing." Journal of the American Academy of Audiology 26, no. 04 (April 2015): 384–92. http://dx.doi.org/10.3766/jaaa.26.4.6.
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Background: Integration of information presented to the two ears has been shown to manifest in binaural interaction components (BICs) that occur along the ascending auditory pathways. In humans, BICs have been studied predominantly at the brainstem and thalamocortical levels; however, understanding of higher cortically driven mechanisms of binaural hearing is limited. Purpose: To explore whether BICs are evident in auditory event-related potentials (AERPs) during the advanced perceptual and postperceptual stages of cortical processing. Research Design: The AERPs N1, P3, and a late negative component (LNC) were recorded from multiple site electrodes while participants performed an oddball discrimination task that consisted of natural speech syllables (/ka/ vs. /ta/) that differed by place-of-articulation. Participants were instructed to respond to the target stimulus (/ta/) while performing the task in three listening conditions: monaural right, monaural left, and binaural. Study Sample: Fifteen (21–32 yr) young adults (6 females) with normal hearing sensitivity. Data Collection and Analysis: By subtracting the response to target stimuli elicited in the binaural condition from the sum of responses elicited in the monaural right and left conditions, the BIC waveform was derived and the latencies and amplitudes of the components were measured. The maximal interaction was calculated by dividing BIC amplitude by the summed right and left response amplitudes. In addition, the latencies and amplitudes of the AERPs to target stimuli elicited in the monaural right, monaural left, and binaural listening conditions were measured and subjected to analysis of variance with repeated measures testing the effect of listening condition and laterality. Results: Three consecutive BICs were identified at a mean latency of 129, 406, and 554 msec, and were labeled N1-BIC, P3-BIC, and LNC-BIC, respectively. Maximal interaction increased significantly with progression of auditory processing from perceptual to postperceptual stages and amounted to 51%, 55%, and 75% of the sum of monaural responses for N1-BIC, P3-BIC, and LNC-BIC, respectively. Binaural interaction manifested in a decrease of the binaural response compared to the sum of monaural responses. Furthermore, listening condition affected P3 latency only, whereas laterality effects manifested in enhanced N1 amplitudes at the left (T3) vs. right (T4) scalp electrode and in a greater left–right amplitude difference in the right compared to left listening condition. Conclusions: The current AERP data provides evidence for the occurrence of cortical BICs during perceptual and postperceptual stages, presumably reflecting ongoing integration of information presented to the two ears at the final stages of auditory processing. Increasing binaural interaction with the progression of the auditory processing sequence (N1 to LNC) may support the notion that cortical BICs reflect inherited interactions from preceding stages of upstream processing together with discrete cortical neural activity involved in binaural processing. Clinically, an objective measure of cortical binaural processing has the potential of becoming an appealing neural correlate of binaural behavioral performance.
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Guyonneau, Rudy, Rufin VanRullen, and Simon J. Thorpe. "Neurons Tune to the Earliest Spikes Through STDP." Neural Computation 17, no. 4 (April 1, 2005): 859–79. http://dx.doi.org/10.1162/0899766053429390.
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Spike timing-dependent plasticity (STDP) is a learning rule that modifies the strength of a neuron's synapses as a function of the precise temporal relations between input and output spikes. In many brains areas, temporal aspects of spike trains have been found to be highly reproducible. How will STDP affect a neuron's behavior when it is repeatedly presented with the same input spike pattern? We show in this theoretical study that repeated inputs systematically lead to a shaping of the neuron's selectivity, emphasizing its very first input spikes, while steadily decreasing the postsynaptic response latency. This was obtained under various conditions of background noise, and even under conditions where spiking latencies and firing rates, or synchrony, provided conflicting informations. The key role of first spikes demonstrated here provides further support for models using a single wave of spikes to implement rapid neural processing.
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Lorez, M. "Neural control of hindleg steering in flight in the locust." Journal of Experimental Biology 198, no. 4 (April 1, 1995): 869–75. http://dx.doi.org/10.1242/jeb.198.4.869.
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Corrective flight steering with the hindlegs was investigated in intact tethered flying locusts inside a wind tunnel as well as in animals dissected for intracellular recording and showing fictive flight activity. In intact tethered flying animals, activity in the second coxal abductor muscle (M126) was highly correlated with hindleg steering and was coupled to the elevator phase of the flight cycle. Fictive flight and steering could also be elicited in animals dissected for intracellular recording of motoneurones innervating M126. During fictive flight activity, motoneurones 126 were rhythmically excited in the elevator phase, presumably from central elements of the neuronal oscillator generating the flight motor pattern, as is the case for motoneurones innervating wing muscles. During fictive straight flight, this input was subthreshold, and it could be demonstrated that simulated deviation from the flight course resulted in recruitment of motoneurones 126. Statistical analysis of the latencies of fast muscle spikes in M126 and in one wing elevator muscle showed that both received common input during flight steering. One source of this common input was identified as the sensory information from the lateral ocelli, which play an important role in the detection of course deviation. The experiments demonstrated that processing in the sensory-motor system for hindleg steering is probably organized in a very similar way to that responsible for steering with the wings.