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1
Volkmann, Frances C. "Human visual suppression." Vision Research 26, no. 9 (January 1986): 1401–16. http://dx.doi.org/10.1016/0042-6989(86)90164-1.
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2
Kim, Back-Soon, Ku-Soo Guen, Eui-Kyung Bang, Eui-Kyung Goh, and Kyong-Myong Chon. "Visuaul suppression test in normal subjects." Journal of Clinical Otolaryngology Head and Neck Surgery 2, no. 1 (May 1991): 51–57. http://dx.doi.org/10.35420/jcohns.1991.2.1.51.
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3
DeAngelis, G. C., J. G. Robson, I. Ohzawa, and R. D. Freeman. "Organization of suppression in receptive fields of neurons in cat visual cortex." Journal of Neurophysiology 68, no. 1 (July 1, 1992): 144–63. http://dx.doi.org/10.1152/jn.1992.68.1.144.
Повний текст джерелаАнотація:
1. The response to an optimally oriented stimulus of both simple and complex cells in the cat's striate visual cortex (area 17) can be suppressed by the superposition of an orthogonally oriented drifting grating. This effect is referred to as cross-orientation suppression. We have examined the spatial organization and tuning characteristics of this suppressive effect with the use of extracellular recording techniques. 2. For a total of 75 neurons, we have measured the size of each cell's excitatory receptive field by use of rectangular patches of drifting sinusoidal gratings presented at the optimal orientation and spatial frequency. The length and width of these grating patches are varied independently. Receptive-field length and width are determined from the dimensions of the smallest grating patch required to elicit a maximal response. 3. The extent of the area from which cross-orientation suppression originates has been measured in an analogous manner. Each neuron is excited by a patch of drifting grating the same size as the receptive field. The response to this stimulus is modulated by a superimposed patch of grating having an orthogonal orientation. After selecting the spatial frequency that produces maximal suppression, the response of each cell is examined as a function of the length and width of the orthogonal (suppressive) grating patch. Results from 29 cells show that the dimensions of the orthogonal grating patch required to elicit maximal suppression are similar to, or smaller than, the dimensions of the excitatory receptive field. Thus cross-orientation suppression originates from within the receptive field. 4. For some cells the spatial frequency tuning of the suppressive effect is much broader than the spatial frequency tuning for excitation. In these cases it is possible to find a spatial frequency that produces suppression but not excitation. With the use of a suppressive stimulus having this spatial frequency, we examined the strength of suppression as a function of orientation for 11 cells. These tests show that suppression occurs at all orientations, including the preferred orientation for excitation. In some cases, suppression is somewhat stronger at the preferred orientation for excitation than at any other orientation. 5. For 12 cells we varied the relative spatial phase between the optimally oriented and orthogonal gratings. In all cases the magnitude of suppression is largely independent of the relative spatial phase. 6. For three binocular cells we examined whether the suppressive effect of a grating oriented orthogonal to the optimum could be mediated dichoptically.(ABSTRACT TRUNCATED AT 400 WORDS)
4
Kimura, Rui, and Izumi Ohzawa. "Time Course of Cross-Orientation Suppression in the Early Visual Cortex." Journal of Neurophysiology 101, no. 3 (March 2009): 1463–79. http://dx.doi.org/10.1152/jn.90681.2008.
Повний текст джерелаАнотація:
Responses of a visual neuron to optimally oriented stimuli can be suppressed by a superposition of another grating with a different orientation. This effect is known as cross-orientation suppression. However, it is still not clear whether the effect is intracortical in origin or a reflection of subcortical processes. To address this issue, we measured spatiotemporal responses to a plaid pattern, a superposition of two gratings, as well as to individual component gratings (optimal and mask) using a subspace reverse-correlation method. Suppression for the plaid was evaluated by comparing the response to that for the optimal grating. For component stimuli, excitatory and negative responses were defined as responses more positive and negative, respectively, than that to a blank stimulus. The suppressive effect for plaids was observed in the vast majority of neurons. However, only ∼30% of neurons showed the negative response to mask-only gratings. The magnitudes of negative responses to mask-only stimuli were correlated with the degree of suppression for plaid stimuli. Comparing the latencies, we found that the suppression for the plaids starts at about the same time or slightly later than the response onset for the optimal grating and reaches its maximum at about the same time as the peak latency for the mask-only grating. Based on these results, we propose that in addition to the suppressive effect originating at the subcortical stage, delayed suppressive signals derived from the intracortical networks act on the neuron to generate cross-orientation suppression.
5
Mrsic-Flogel, Thomas, and Mark Hübener. "Visual Cortex: Suppression by Depression?" Current Biology 12, no. 16 (August 2002): R547—R549. http://dx.doi.org/10.1016/s0960-9822(02)01049-7.
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6
Bishop, Christopher W., Sam London, and Lee M. Miller. "Visual Influences on Echo Suppression." Current Biology 21, no. 3 (February 2011): 221–25. http://dx.doi.org/10.1016/j.cub.2010.12.051.
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7
Kadunce, Daniel C., J. William Vaughan, Mark T. Wallace, Gyorgy Benedek, and Barry E. Stein. "Mechanisms of Within- and Cross-Modality Suppression in the Superior Colliculus." Journal of Neurophysiology 78, no. 6 (December 1, 1997): 2834–47. http://dx.doi.org/10.1152/jn.1997.78.6.2834.
Повний текст джерелаАнотація:
Kadunce, Daniel C., J. William Vaughan, Mark T. Wallace, Gyorgy Benedek, and Barry E. Stein. Mechanisms of within- and cross-modality suppression in the superior colliculus. J. Neurophysiol. 78: 2834–2847, 1997. The present studies were initiated to explore the basis for the response suppression that occurs in cat superior colliculus (SC) neurons when two spatially disparate stimuli are presented simultaneously or in close temporal proximity to one another. Of specific interest was examining the possibility that suppressive regions border the receptive fields (RFs) of unimodal and multisensory SC neurons and, when activated, degrade the neuron's responses to excitatory stimuli. Both within- and cross-modality effects were examined. An example of the former is when a response to a visual stimulus within its RF is suppressed by a second visual stimulus outside the RF. An example of the latter is when the response to a visual stimulus within the visual RF is suppressed when a stimulus from a different modality (e.g., auditory) is presented outside its (i.e., auditory) RF. Suppressive regions were found bordering visual, auditory, and somatosensory RFs. Despite significant modality-specific differences in the incidence and effectiveness of these regions, they were generally quite potent regardless of the modality. In the vast majority (85%) of cases, responses to the excitatory stimulus were degraded by ≥50% by simultaneously stimulating the suppressive region. Contrary to expectations and previous speculations, the effects of activating these suppressive regions often were quite specific. Thus powerful within-modality suppression could be demonstrated in many multisensory neurons in which cross-modality suppression could not be generated. However, the converse was not true. If an extra-RF stimulus inhibited center responses to stimuli of a different modality, it also would suppress center responses to stimuli of its own modality. Thus when cross-modality suppression was demonstrated, it was always accompanied by within-modality suppression. These observations suggest that separate mechanisms underlie within- and cross-modality suppression in the SC. Because some modality-specific tectopetal structures contain neurons with suppressive regions bordering their RFs, the within-modality suppression observed in the SC simply may reflect interactions taking place at the level of one input channel. However, the presence of modality-specific suppression at the level of one input channel would have no effect on the excitation initiated via another input channel. Given the modality-specificity of tectopetal inputs, it appears that cross-modality interactions require the convergence of two or more modality-specific inputs onto the same SC neuron and that the expression of these interactions depends on the internal circuitry of the SC. This allows a cross-modality suppressive signal to be nonspecific and to degrade any and all of the neuron's excitatory inputs.
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Joo, Sung Jun, and Scott O. Murray. "Contextual effects in human visual cortex depend on surface structure." Journal of Neurophysiology 111, no. 9 (May 1, 2014): 1783–91. http://dx.doi.org/10.1152/jn.00671.2013.
Повний текст джерелаАнотація:
Neural responses in early visual cortex depend on stimulus context. One of the most well-established context-dependent effects is orientation-specific surround suppression: the neural response to a stimulus inside the receptive field of a neuron (“target”) is suppressed when it is surrounded by iso-oriented compared with orthogonal stimuli (“flankers”). Despite the importance of orientation-specific surround suppression in potentially mediating a number of important perceptual effects, including saliency, contour integration, and orientation discrimination, the underlying neural mechanisms remain unknown. The suppressive signal could be inherited from precortical areas as early as the retina and thalamus, arise from local circuits through horizontal connections, or be fed back from higher visual cortex. Here, we show, using two different methodologies, measurements of scalp-recorded event-related potentials (ERPs) and behavioral contrast adaptation aftereffects in humans, that orientation-specific surround suppression is dependent on the surface structure in an image. When the target and flankers can be grouped on the same surface (independent of their distance), orientation-specific surround suppression occurs. When the target and flankers are on different surfaces (independent of their distance), orientation-specific surround suppression does not occur. Our results demonstrate a surprising role of high-level, global processes such as grouping in determining when contextual effects occur in early visual cortex.
9
Baker, Daniel H., Greta Vilidaite, and Alex R. Wade. "Steady-state measures of visual suppression." PLOS Computational Biology 17, no. 10 (October 13, 2021): e1009507. http://dx.doi.org/10.1371/journal.pcbi.1009507.
Повний текст джерелаАнотація:
In the early visual system, suppression occurs between neurons representing different stimulus properties. This includes features such as orientation (cross-orientation suppression), eye-of-origin (interocular suppression) and spatial location (surround suppression), which are thought to involve distinct anatomical pathways. We asked if these separate routes to suppression can be differentiated by their pattern of gain control on the contrast response function measured in human participants using steady-state electroencephalography. Changes in contrast gain shift the contrast response function laterally, whereas changes in response gain scale the function vertically. We used a Bayesian hierarchical model to summarise the evidence for each type of gain control. A computational meta-analysis of 16 previous studies found the most evidence for contrast gain effects with overlaid masks, but no clear evidence favouring either response gain or contrast gain for other mask types. We then conducted two new experiments, comparing suppression from four mask types (monocular and dichoptic overlay masks, and aligned and orthogonal surround masks) on responses to sine wave grating patches flickering at 5Hz. At the occipital pole, there was strong evidence for contrast gain effects in all four mask types at the first harmonic frequency (5Hz). Suppression generally became stronger at more lateral electrode sites, but there was little evidence of response gain effects. At the second harmonic frequency (10Hz) suppression was stronger overall, and involved both contrast and response gain effects. Although suppression from different mask types involves distinct anatomical pathways, gain control processes appear to serve a common purpose, which we suggest might be to suppress less reliable inputs.
10
Lunghi, Claudia, Luca Lo Verde, and David Alais. "Touch Accelerates Visual Awareness." i-Perception 8, no. 1 (January 2017): 204166951668698. http://dx.doi.org/10.1177/2041669516686986.
Повний текст джерелаАнотація:
To efficiently interact with the external environment, our nervous system combines information arising from different sensory modalities. Recent evidence suggests that cross-modal interactions can be automatic and even unconscious, reflecting the ecological relevance of cross-modal processing. Here, we use continuous flash suppression (CFS) to directly investigate whether haptic signals can interact with visual signals outside of visual awareness. We measured suppression durations of visual gratings rendered invisible by CFS either during visual stimulation alone or during visuo-haptic stimulation. We found that active exploration of a haptic grating congruent in orientation with the suppressed visual grating reduced suppression durations both compared with visual-only stimulation and to incongruent visuo-haptic stimulation. We also found that the facilitatory effect of touch on visual suppression disappeared when the visual and haptic gratings were mismatched in either spatial frequency or orientation. Together, these results demonstrate that congruent touch can accelerate the rise to consciousness of a suppressed visual stimulus and that this unconscious cross-modal interaction depends on visuo-haptic congruency. Furthermore, since CFS suppression is thought to occur early in visual cortical processing, our data reinforce the evidence suggesting that visuo-haptic interactions can occur at the earliest stages of cortical processing.
11
WALKER, GARY A., IZUMI OHZAWA, and RALPH D. FREEMAN. "Suppression outside the classical cortical receptive field." Visual Neuroscience 17, no. 3 (May 2000): 369–79. http://dx.doi.org/10.1017/s0952523800173055.
Повний текст джерелаАнотація:
The important visual stimulus parameters for a given cell are defined by the classical receptive field (CRF). However, cells are also influenced by visual stimuli presented in areas surrounding the CRF. The experiments described here were conducted to determine the incidence and nature of CRF surround influences in the primary visual cortex. From extracellular recordings in the cat's striate cortex, we find that for over half of the cells investigated (56%, 153/271), the effect of stimulation in the surround of the CRF is to suppress the neuron's activity by at least 10% compared to the response to a grating presented within the CRF alone. For the remainder of the cells, the interactions were minimal and a few were of a facilitatory nature. In this paper, we focus on the suppressive interactions. Simple and complex cell types exhibit equal incidences of surround suppression. Suppression is observed for cells in all layers, and its degree is strongly correlated between the two eyes for binocular neurons. These results show that surround suppression is a prevalent form of inhibition and may play an important role in visual processing.
12
Furukawa, Tomoyasu, Michitaka Watanabe, Yoshio Masaki, Akihiko Kanou, Youko Yamaguchi, and Ginichirou Ichikawa. "Visual Suppression Test in Degenerative Diseases." Equilibrium Research 57, no. 6 (1998): 550–55. http://dx.doi.org/10.3757/jser.57.550.
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Freeman, Tobe C. B., Séverine Durand, Daniel C. Kiper, and Matteo Carandini. "Suppression without Inhibition in Visual Cortex." Neuron 35, no. 4 (August 2002): 759–71. http://dx.doi.org/10.1016/s0896-6273(02)00819-x.
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14
Burr, David C., Michael J. Morgan, and M. Concetta Morrone. "Saccadic suppression precedes visual motion analysis." Current Biology 9, no. 20 (October 1999): 1207–9. http://dx.doi.org/10.1016/s0960-9822(00)80028-7.
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15
Mizuno, Masahiro, Masaaki Yamane, and Ryuichi Osanai. "Visual suppression test in spinocerebellar degenerations." Practica Oto-Rhino-Laryngologica 81, no. 2 (1988): 165–71. http://dx.doi.org/10.5631/jibirin.81.165.
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16
Desimone, Robert, Jeffrey Moran, Stanley J. Schein, and Mortimer Mishkin. "A role for the corpus callosum in visual area V4 of the macaque." Visual Neuroscience 10, no. 1 (January 1993): 159–71. http://dx.doi.org/10.1017/s095252380000328x.
Повний текст джерелаАнотація:
AbstractThe classically defined receptive fields of V4 cells are confined almost entirely to the contralateral visual field. However, these receptive fields are often surrounded by large, silent suppressive regions, and stimulating the surrounds can cause a complete suppression of response to a simultaneously presented stimulus within the receptive field. We investigated whether the suppressive surrounds might extend across the midline into the ipsilateral visual field and, if so, whether the surrounds were dependent on the corpus callosum, which has a widespread distribution in V4. We found that the surrounds of more than half of the cells tested in the central visual field representation of V4 crossed into the ipsilateral visual field, with some extending up to at least 16 deg from the vertical meridian. Much of this suppression from the ipsilateral field was mediated by the corpus callosum, as section of the callosum dramatically reduced both the strength and extent of the surrounds. There remained, however, some residual suppression that was not further reduced by addition of an anterior commissure lesion. Because the residual ipsilateral suppression was similar in magnitude and extent to that found following section of the optic tract contralateral to the V4 recording, we concluded that it was retinal in origin. Using the same techniques employed in V4, we also mapped the ipsilateral extent of surrounds in the foveal representation of VI in an intact monkey. Results were very similar to those in V4 following commissural or contralateral tract sections. The findings suggest that V4 is a central site for long-range interactions both within and across the two visual hemifields. Taken with previous work, the results are consistent with the notion that the large suppressive surrounds of V4 neurons contribute to the neural mechanisms of color constancy and figure-ground separation.
17
Bishop, Christopher W., Sam London, and Lee M. Miller. "Neural time course of visually enhanced echo suppression." Journal of Neurophysiology 108, no. 7 (October 1, 2012): 1869–83. http://dx.doi.org/10.1152/jn.00175.2012.
Повний текст джерелаАнотація:
Auditory spatial perception plays a critical role in day-to-day communication. For instance, listeners utilize acoustic spatial information to segregate individual talkers into distinct auditory “streams” to improve speech intelligibility. However, spatial localization is an exceedingly difficult task in everyday listening environments with numerous distracting echoes from nearby surfaces, such as walls. Listeners' brains overcome this unique challenge by relying on acoustic timing and, quite surprisingly, visual spatial information to suppress short-latency (1–10 ms) echoes through a process known as “the precedence effect” or “echo suppression.” In the present study, we employed electroencephalography (EEG) to investigate the neural time course of echo suppression both with and without the aid of coincident visual stimulation in human listeners. We find that echo suppression is a multistage process initialized during the auditory N1 (70–100 ms) and followed by space-specific suppression mechanisms from 150 to 250 ms. Additionally, we find a robust correlate of listeners' spatial perception (i.e., suppressing or not suppressing the echo) over central electrode sites from 300 to 500 ms. Contrary to our hypothesis, vision's powerful contribution to echo suppression occurs late in processing (250–400 ms), suggesting that vision contributes primarily during late sensory or decision making processes. Together, our findings support growing evidence that echo suppression is a slow, progressive mechanism modifiable by visual influences during late sensory and decision making stages. Furthermore, our findings suggest that audiovisual interactions are not limited to early, sensory-level modulations but extend well into late stages of cortical processing.
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Wang, Benchi, Joram van Driel, Eduard Ort, and Jan Theeuwes. "Anticipatory Distractor Suppression Elicited by Statistical Regularities in Visual Search." Journal of Cognitive Neuroscience 31, no. 10 (October 2019): 1535–48. http://dx.doi.org/10.1162/jocn_a_01433.
Повний текст джерелаАнотація:
Salient yet irrelevant objects often capture our attention and interfere with our daily tasks. Distraction by salient objects can be reduced by suppressing the location where they are likely to appear. The question we addressed here was whether suppression of frequent distractor locations is already implemented beforehand, in anticipation of the stimulus. Using EEG, we recorded cortical activity of human participants searching for a target while ignoring a salient distractor. The distractor was presented more often at one location than at any other location. We found reduced capture for distractors at frequent locations, indicating that participants learned to avoid distraction. Critically, we found evidence for “proactive suppression” as already “prior to display onset,” there was enhanced power in parieto-occipital alpha oscillations contralateral to the frequent distractor location—a signal known to occur in anticipation of irrelevant information. Locked to display onset, ERP analysis showed a distractor suppression-related distractor positivity (PD) component for this location. Importantly, this PD was found regardless of whether distracting information was presented at the frequent location. In addition, there was an early PD component representing an early attentional index of the frequent distractor location. Our results show anticipatory (proactive) suppression of frequent distractor locations in visual search already starting prior to display onset.
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Malone, Brian J., and Dario L. Ringach. "Dynamics of Tuning in the Fourier Domain." Journal of Neurophysiology 100, no. 1 (July 2008): 239–48. http://dx.doi.org/10.1152/jn.90273.2008.
Повний текст джерелаАнотація:
Neurons in primary visual cortex (area V1) are jointly tuned to the orientation and spatial frequency of sinusoidal stimuli (the Fourier domain). The role that suppressive mechanisms play in shaping the tuning and dynamics of cortical responses remains the subject of debate. Here we used subspace reverse correlation to study the relationship between suppression by nonoptimal stimuli, the spectral-temporal separability of the responses, and their persistence in time. Two clear relationships emerged from our data. First, cells with inseparable responses were often accompanied by suppression to nonpreferred stimuli, while separable responses showed mostly enhancement by their preferred stimuli. Second, inseparable responses were characterized by a longer persistence in time compared with those with separable dynamics. A parametric model that assumes the additive combination of separable enhancement and suppression signals, with suppression constrained to be low-pass in spatial frequency and untuned for orientation, explained the data well. These new findings, in addition to an established correlation between selectivity and suppression for nonoptimal stimuli, clarify how the dynamics and selectivity of cortical responses are shaped by suppressive signals and how their interplay generates the large diversity of responses observed in primary visual cortex.
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Findlay, J. M., R. Walker, V. Brown, I. Gilchrist, and M. Clarke. "Saccade Programming in Strabismic Suppression." Perception 25, no. 1_suppl (August 1996): 47. http://dx.doi.org/10.1068/v96l0303.
Повний текст джерелаАнотація:
Individuals with strabismus frequently show a suppression phenomenon in which part of the visual input in one eye is apparently ignored when both eyes are seeing, although the eye may have normal vision when used monocularly. This is often described as an adaptive response to avoid diplopia. We have examined two patients with microstrabismus (angle of squint less than 5 deg) who show strong suppression but with only mild amblyopia. We studied saccade generation in the two eyes using a red — green anaglyph display which allowed us to present stimuli independently to each eye. When single targets were presented in the suppressing eye, saccadic responses usually occurred. However the latencies of these saccades were increased with respect to those elicited from the normal eye (by about 70 ms for one subject and 270 ms for the other). The amplitudes of the saccades were less consistent than those of the normal eye, and saccades were sometimes made in the opposite direction to the target. We also investigated the remote distractor effect. This effect is found consistently in normal subjects and consists of an increase in the latency of a target-elicited saccade when a distractor is simultaneously presented elsewhere in the visual field. When distractors were presented in the suppressing eye, they had no effect on the latency of saccades to a simultaneous target in the other eye. We conclude that visual stimulation in a suppressing eye has no rapid access to the saccadic system.
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Chen, Chih-Yang, and Ziad M. Hafed. "A neural locus for spatial-frequency specific saccadic suppression in visual-motor neurons of the primate superior colliculus." Journal of Neurophysiology 117, no. 4 (April 1, 2017): 1657–73. http://dx.doi.org/10.1152/jn.00911.2016.
Повний текст джерелаАнотація:
Saccades cause rapid retinal-image shifts that go perceptually unnoticed several times per second. The mechanisms for saccadic suppression have been controversial, in part because of sparse understanding of neural substrates. In this study we uncovered an unexpectedly specific neural locus for spatial frequency-specific saccadic suppression in the superior colliculus (SC). We first developed a sensitive behavioral measure of suppression in two macaque monkeys, demonstrating selectivity to low spatial frequencies similar to that observed in earlier behavioral studies. We then investigated visual responses in either purely visual SC neurons or anatomically deeper visual motor neurons, which are also involved in saccade generation commands. Surprisingly, visual motor neurons showed the strongest visual suppression, and the suppression was dependent on spatial frequency, as in behavior. Most importantly, suppression selectivity for spatial frequency in visual motor neurons was highly predictive of behavioral suppression effects in each individual animal, with our recorded population explaining up to ~74% of behavioral variance even on completely different experimental sessions. Visual SC neurons had mild suppression, which was unselective for spatial frequency and thus only explained up to ~48% of behavioral variance. In terms of spatial frequency-specific saccadic suppression, our results run contrary to predictions that may be associated with a hypothesized SC saccadic suppression mechanism, in which a motor command in the visual motor and motor neurons is first relayed to the more superficial purely visual neurons, to suppress them and to then potentially be fed back to cortex. Instead, an extraretinal modulatory signal mediating spatial-frequency-specific suppression may already be established in visual motor neurons. NEW & NOTEWORTHY Saccades, which repeatedly realign the line of sight, introduce spurious signals in retinal images that normally go unnoticed. In part, this happens because of perisaccadic suppression of visual sensitivity, which is known to depend on spatial frequency. We discovered that a specific subtype of superior colliculus (SC) neurons demonstrates spatial-frequency-dependent suppression. Curiously, it is the neurons that help mediate the saccadic command itself that exhibit such suppression, and not the purely visual ones.
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Santer, Roger D., Richard Stafford, and F. Claire Rind. "Retinally-generated saccadic suppression of a locust looming-detector neuron: investigations using a robot locust." Journal of The Royal Society Interface 1, no. 1 (November 22, 2004): 61–77. http://dx.doi.org/10.1098/rsif.2004.0007.
Повний текст джерелаАнотація:
A fundamental task performed by many visual systems is to distinguish apparent motion caused by eye movements from real motion occurring within the environment. During saccadic eye movements, this task is achieved by inhibitory signals of central and retinal origin that suppress the output of motion-detecting neurons. To investigate the retinally-generated component of this suppression, we used a computational model of a locust looming-detecting pathway that experiences saccadic suppression. This model received input from the camera of a mobile robot that performed simple saccade-like movements, allowing the model's response to simplified real stimuli to be tested. Retinally-generated saccadic suppression resulted from two inhibitory mechanisms within the looming-detector's input architecture. One mechanism fed inhibition forward through the network, inhibiting the looming-detector's initial response to movement. The second spread inhibition laterally within the network, suppressing the looming-detector's maintained response to movement. These mechanisms prevent a loomingdetector model response to whole-field visual stimuli. In the locust, this mechanism of saccadic suppression may operate in addition to centrally-generated suppression. Because lateral inhibition is a common feature of early visual processing in many organisms, we discuss whether the mechanism of retinally-generated saccadic suppression found in the locust looming-detector model may also operate in these species.
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Izawa, Yoshiko, Hisao Suzuki, and Yoshikazu Shinoda. "Suppression of Visually and Memory-Guided Saccades Induced by Electrical Stimulation of the Monkey Frontal Eye Field. I. Suppression of Ipsilateral Saccades." Journal of Neurophysiology 92, no. 4 (October 2004): 2248–60. http://dx.doi.org/10.1152/jn.01021.2003.
Повний текст джерелаАнотація:
When a saccade occurs to an interesting object, visual fixation holds its image on the fovea and suppresses saccades to other objects. Electrical stimulation of the frontal eye field (FEF) has been reported to elicit saccades, and recently also to suppress saccades. This study was performed to characterize properties of the suppression of visually guided (Vsacs) and memory-guided saccades (Msacs) induced by electrical stimulation of the FEF in trained monkeys. For any given stimulation site, we determined the threshold for electrically evoked saccades (Esacs) at ≤50 μA and then examined suppressive effects of stimulation at the same site on Vsacs and Msacs. FEF stimulation suppressed the initiation of both Vsacs and Msacs during and about 50 ms after stimulation at stimulus intensities lower than those for eliciting Esacs, but did not affect the vector of these saccades. Suppression occurred for ipsiversive but not contraversive saccades, and more strongly for saccades with larger amplitudes and those with initial eye positions shifted more in the saccadic direction. The most effective stimulation timing for suppression was about 50 ms before saccade onset, which suggests that suppression occurred in the efferent pathway for generating Vsacs at the premotor rather than the motoneuronal level, most probably in the superior colliculus and/or the paramedian pontine reticular formation. Suppression sites of ipsilateral saccades were distributed over the classical FEF where saccade-related movement neurons were observed. The results suggest that the FEF may play roles in not only generating contraversive saccades but also maintaining visual fixation by suppressing ipsiversive saccades.
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Berman, Rebecca A., James Cavanaugh, Kerry McAlonan, and Robert H. Wurtz. "A circuit for saccadic suppression in the primate brain." Journal of Neurophysiology 117, no. 4 (April 1, 2017): 1720–35. http://dx.doi.org/10.1152/jn.00679.2016.
Повний текст джерелаАнотація:
Saccades should cause us to see a blur as the eyes sweep across a visual scene. Specific brain mechanisms prevent this by producing suppression during saccades. Neuronal correlates of such suppression were first established in the visual superficial layers of the superior colliculus (SC) and subsequently have been observed in cortical visual areas, including the middle temporal visual area (MT). In this study, we investigated suppression in a recently identified circuit linking visual SC (SCs) to MT through the inferior pulvinar (PI). We examined responses to visual stimuli presented just before saccades to reveal a neuronal correlate of suppression driven by a copy of the saccade command, referred to as a corollary discharge. We found that visual responses were similarly suppressed in SCs, PI, and MT. Within each region, suppression of visual responses occurred with saccades into both visual hemifields, but only in the contralateral hemifield did this suppression consistently begin before the saccade (~100 ms). The consistency of the signal along the circuit led us to hypothesize that the suppression in MT was influenced by input from the SC. We tested this hypothesis in one monkey by inactivating neurons within the SC and found evidence that suppression in MT depends on corollary discharge signals from motor SC (SCi). Combining these results with recent findings in rodents, we propose a complete circuit originating with corollary discharge signals in SCi that produces suppression in visual SCs, PI, and ultimately, MT cortex. NEW & NOTEWORTHY A fundamental puzzle in visual neuroscience is that we frequently make rapid eye movements (saccades) but seldom perceive the visual blur accompanying each movement. We investigated neuronal correlates of this saccadic suppression by recording from and perturbing a recently identified circuit from brainstem to cortex. We found suppression at each stage, with evidence that it was driven by an internally generated signal. We conclude that this circuit contributes to neuronal suppression of visual signals during eye movements.
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Vanegas, M. Isabel, Annabelle Blangero, and Simon P. Kelly. "Electrophysiological indices of surround suppression in humans." Journal of Neurophysiology 113, no. 4 (February 15, 2015): 1100–1109. http://dx.doi.org/10.1152/jn.00774.2014.
Повний текст джерелаАнотація:
Surround suppression is a well-known example of contextual interaction in visual cortical neurophysiology, whereby the neural response to a stimulus presented within a neuron's classical receptive field is suppressed by surrounding stimuli. Human psychophysical reports present an obvious analog to the effects seen at the single-neuron level: stimuli are perceived as lower-contrast when embedded in a surround. Here we report on a visual paradigm that provides relatively direct, straightforward indices of surround suppression in human electrophysiology, enabling us to reproduce several well-known neurophysiological and psychophysical effects, and to conduct new analyses of temporal trends and retinal location effects. Steady-state visual evoked potentials (SSVEP) elicited by flickering “foreground” stimuli were measured in the context of various static surround patterns. Early visual cortex geometry and retinotopic organization were exploited to enhance SSVEP amplitude. The foreground response was strongly suppressed as a monotonic function of surround contrast. Furthermore, suppression was stronger for surrounds of matching orientation than orthogonally-oriented ones, and stronger at peripheral than foveal locations. These patterns were reproduced in psychophysical reports of perceived contrast, and peripheral electrophysiological suppression effects correlated with psychophysical effects across subjects. Temporal analysis of SSVEP amplitude revealed short-term contrast adaptation effects that caused the foreground signal to either fall or grow over time, depending on the relative contrast of the surround, consistent with stronger adaptation of the suppressive drive. This electrophysiology paradigm has clinical potential in indexing not just visual deficits but possibly gain control deficits expressed more widely in the disordered brain.
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Tanaka, Hiroki, and Izumi Ohzawa. "Surround Suppression of V1 Neurons Mediates Orientation-Based Representation of High-Order Visual Features." Journal of Neurophysiology 101, no. 3 (March 2009): 1444–62. http://dx.doi.org/10.1152/jn.90749.2008.
Повний текст джерелаАнотація:
Neurons with surround suppression have been implicated in processing high-order visual features such as contrast- or texture-defined boundaries and subjective contours. However, little is known regarding how these neurons encode high-order visual information in a systematic manner as a population. To address this issue, we have measured detailed spatial structures of classical center and suppressive surround regions of receptive fields of primary visual cortex (V1) neurons and examined how a population of such neurons allow encoding of various high-order features and shapes in visual scenes. Using a novel method to reconstruct structures, we found that the center and surround regions are often both elongated parallel to each other, reminiscent of on and off subregions of simple cells without surround suppression. These structures allow V1 neurons to extract high-order contours of various orientations and spatial frequencies, with a variety of optimal values across neurons. The results show that a wide range of orientations and widths of the high-order features are systematically represented by the population of V1 neurons with surround suppression.
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Williams, Adrian L., Krishna D. Singh, and Andrew T. Smith. "Surround Modulation Measured With Functional MRI in the Human Visual Cortex." Journal of Neurophysiology 89, no. 1 (January 1, 2003): 525–33. http://dx.doi.org/10.1152/jn.00048.2002.
Повний текст джерелаАнотація:
Visual context profoundly influences 1) the responses of mammalian visual neurons and 2) the perceptual sensitivity of human observers to localized visual stimuli. We present data from functional MRI studies demonstrating contextual modulation in the human visual cortex. Subjects viewed a circular grating patch that was continuously present. A surround grating was added in an on–off block design to reveal its effect on the central region. Stimulus-correlated activation was quantified and visualized on a flattened map of the occipital gray matter. Modulation was measured in a region of interest activated by the central grating alone. The observed effects were predominantly suppressive, consistent with the effects typically found in single neurons and perception. Suppression was greatest when the surround and center had the same orientation and was reduced or absent when it was orthogonal. When spatial phase was manipulated, suppression was greatest for in-phase center/surround gratings and much reduced or reversed (facilitation) for opposite-phase stimuli. With eccentric stimulus presentation, suppression was reduced and facilitation became more common. The findings provide a direct demonstration of the existence of powerful and stimulus-specific surround effects in human visual cortex.
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Tsui, James M. G., and Christopher C. Pack. "Contrast sensitivity of MT receptive field centers and surrounds." Journal of Neurophysiology 106, no. 4 (October 2011): 1888–900. http://dx.doi.org/10.1152/jn.00165.2011.
Повний текст джерелаАнотація:
Neurons throughout the visual system have receptive fields with both excitatory and suppressive components. The latter are responsible for a phenomenon known as surround suppression, in which responses decrease as a stimulus is extended beyond a certain size. Previous work has shown that surround suppression in the primary visual cortex depends strongly on stimulus contrast. Such complex center-surround interactions are thought to relate to a variety of functions, although little is known about how they affect responses in the extrastriate visual cortex. We have therefore examined the interaction of center and surround in the middle temporal (MT) area of the macaque ( Macaca mulatta) extrastriate cortex by recording neuronal responses to stimuli of different sizes and contrasts. Our findings indicate that surround suppression in MT is highly contrast dependent, with the strongest suppression emerging unexpectedly at intermediate stimulus contrasts. These results can be explained by a simple model that takes into account the nonlinear contrast sensitivity of the neurons that provide input to MT. The model also provides a qualitative link to previous reports of a topographic organization of area MT based on clusters of neurons with differing surround suppression strength. We show that this organization can be detected in the gamma-band local field potentials (LFPs) and that the model parameters can predict the contrast sensitivity of these LFP responses. Overall our results show that surround suppression in area MT is far more common than previously suspected, highlighting the potential functional importance of the accumulation of nonlinearities along the dorsal visual pathway.
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Vaiceliunaite, Agne, Sinem Erisken, Florian Franzen, Steffen Katzner, and Laura Busse. "Spatial integration in mouse primary visual cortex." Journal of Neurophysiology 110, no. 4 (August 15, 2013): 964–72. http://dx.doi.org/10.1152/jn.00138.2013.
Повний текст джерелаАнотація:
Responses of many neurons in primary visual cortex (V1) are suppressed by stimuli exceeding the classical receptive field (RF), an important property that might underlie the computation of visual saliency. Traditionally, it has proven difficult to disentangle the underlying neural circuits, including feedforward, horizontal intracortical, and feedback connectivity. Since circuit-level analysis is particularly feasible in the mouse, we asked whether neural signatures of spatial integration in mouse V1 are similar to those of higher-order mammals and investigated the role of parvalbumin-expressing (PV+) inhibitory interneurons. Analogous to what is known from primates and carnivores, we demonstrate that, in awake mice, surround suppression is present in the majority of V1 neurons and is strongest in superficial cortical layers. Anesthesia with isoflurane-urethane, however, profoundly affects spatial integration: it reduces the laminar dependency, decreases overall suppression strength, and alters the temporal dynamics of responses. We show that these effects of brain state can be parsimoniously explained by assuming that anesthesia affects contrast normalization. Hence, the full impact of suppressive influences in mouse V1 cannot be studied under anesthesia with isoflurane-urethane. To assess the neural circuits of spatial integration, we targeted PV+ interneurons using optogenetics. Optogenetic depolarization of PV+ interneurons was associated with increased RF size and decreased suppression in the recorded population, similar to effects of lowering stimulus contrast, suggesting that PV+ interneurons contribute to spatial integration by affecting overall stimulus drive. We conclude that the mouse is a promising model for circuit-level mechanisms of spatial integration, which relies on the combined activity of different types of inhibitory interneurons.
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Alitto, Henry J., and W. Martin Usrey. "Surround suppression and temporal processing of visual signals." Journal of Neurophysiology 113, no. 7 (April 2015): 2605–17. http://dx.doi.org/10.1152/jn.00480.2014.
Повний текст джерелаАнотація:
Extraclassical surround suppression strongly modulates responses of neurons in the retina, lateral geniculate nucleus (LGN), and primary visual cortex. Although a great deal is known about the spatial properties of extraclassical suppression and the role it serves in stimulus size tuning, relatively little is known about how extraclassical suppression shapes visual processing in the temporal domain. We recorded the spiking activity of retinal ganglion cells and LGN neurons in the cat to test the hypothesis that extraclassical suppression influences temporal features of visual responses in the early visual system. Our results demonstrate that extraclassical suppression not only shifts the distribution of interspike intervals in a manner that decreases the efficacy of neuronal communication, it also decreases the reliability of neuronal responses to visual stimuli and it decreases the duration of visual responses, an effect that underlies a rightward shift in the temporal frequency tuning of LGN neurons. Taken together, these results reveal a dynamic relationship between extraclassical suppression and the temporal features of neuronal responses.
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Sceniak, Michael P., Soumya Chatterjee, and Edward M. Callaway. "Visual Spatial Summation in Macaque Geniculocortical Afferents." Journal of Neurophysiology 96, no. 6 (December 2006): 3474–84. http://dx.doi.org/10.1152/jn.00734.2006.
Повний текст джерелаАнотація:
The spatial summation properties of visual signals were analyzed for geniculocortical afferents in the primary visual cortex (V1) of anesthetized paralyzed macaque monkeys. Afferent input responses were recorded extracellularly during cortical inactivation through superfusion of the cortex with muscimol, allowing investigation of lateral geniculate nucleus of the thalamus (LGN) cell properties in the absence of cortical feedback. Responses from afferent inputs were classified as magno-, parvo-, or koniocellular based on anatomical organization within the cortex, established through histological reconstructions, and visual response wavelength sensitivity. More than 80% of afferents showed strong surround suppression [suppression index (SI) >0.5] and 14% showed negligible surround suppression (SI < 0.2). Afferent responses with weak and strong surround suppression were found throughout cortical input layers 4C and 4A. High-contrast estimates of the spatial extent of the classical surround were similar to the nonclassical surround. The classical and nonclassical surrounds were, on average, 1.5-fold larger than the excitatory center. Unlike neurons within V1, the spatial extent of excitatory summation for geniculocortical afferents was contrast invariant. Nonclassical surround suppression showed slight contrast dependency with estimates larger (20%) at lower contrasts and stronger at higher contrasts (13%). Surround suppression is inherent in cortical input responses and likely derives from lateral inhibition in either the LGN or retina. Although surround suppression within afferent responses increases slightly with contrast, the spatial spread of excitation remains fixed with contrast. This argues for distinct mechanisms of action for contrast-dependent modulation in cortical and subcortical responses.
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DURAND, SÉVERINE, TOBE C. B. FREEMAN, and MATTEO CARANDINI. "Temporal properties of surround suppression in cat primary visual cortex." Visual Neuroscience 24, no. 5 (August 9, 2007): 679–90. http://dx.doi.org/10.1017/s0952523807070563.
Повний текст джерелаАнотація:
The responses of neurons in primary visual cortex (V1) are suppressed by stimuli presented in the region surrounding the receptive field. There is debate as to whether this surround suppression is due to intracortical inhibition, is inherited from lateral geniculate nucleus (LGN), or is due to a combination of these factors. The mechanisms involved in surround suppression may differ from those involved in suppression within the receptive field, which is called cross-orientation suppression. To compare surround suppression to cross-orientation suppression, and to help elucidate its underlying mechanisms, we studied its temporal properties in anesthetized and paralyzed cats. We first measured the temporal resolution of suppression. While cat LGN neurons respond vigorously to drift rates up to 30 Hz, most cat V1 neurons stop responding above 10–15 Hz. If suppression originated in cortical responses, therefore, it should disappear above such drift rates. In a majority of cells, surround suppression decreased substantially when surround drift rate was above ∼15 Hz, but some neurons demonstrated suppression with surround drift rates as high as 21 Hz. We then measured the susceptibility of suppression to contrast adaptation. Contrast adaptation reduces responses of cortical neurons much more than those of LGN neurons. If suppression originated in cortical responses, therefore, it should be reduced by adaptation. Consistent with this hypothesis, we found that prolonged exposure to the surround stimulus decreased the strength of surround suppression. The results of both experiments differ markedly from those previously obtained in a study of cross-orientation suppression, whose temporal properties were found to resemble those of LGN neurons. Our results provide further evidence that these two forms of suppression are due to different mechanisms. Surround suppression can be explained by a mixture of thalamic and cortical influences. It could also arise entirely from intracortical inhibition, but only if inhibitory neurons respond to somewhat higher drift rates than most cortical cells.
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Prabhu, Prashanth, Akriti Kumar, Raveendran Revathi, and Shezeen Gafoor. "EFFECT OF VISUAL ATTENTION ON CONTRALATERAL SUPPRESSION OF ACOUSTIC REFLEXES." Journal of Hearing Science 5, no. 4 (December 31, 2015): 26–32. http://dx.doi.org/10.17430/8893574.
Повний текст джерелаАнотація:
BackgroundCortical functions such as attention can affect the functioning of the medial efferent auditory system. This study attempts to determine the effect of visual attention on contralateral suppression of acoustic reflexes.Material and MethodsContralateral suppression of acoustic reflex threshold (CSART) and contralateral suppression of acoustic reflex amplitude (CSARA) were determined in 30 normal hearing individuals at 500, 1000, and 2000 Hz. CSART and CSARA were determined for four visual attention tasks: no attention, passive attention, and two active visual attention tasks.ResultsContralateral suppression of acoustic reflexes was enhanced in the active visual attention condition compared to the no visual attention condition. No significant difference was observed across gender in any of the conditions.ConclusionsVisual attention tasks can have a direct effect on the medial auditory efferent system and hence needs to be monitored. To enhance suppression a well-controlled active visual attention task should be used.
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Wright, Kenneth Weston, James P. Ary, Tracey J. Shors, and K. Jeffrey Eriksen. "Suppression and the Pattern Visual Evoked Potential." Journal of Pediatric Ophthalmology & Strabismus 23, no. 5 (September 1986): 252–57. http://dx.doi.org/10.3928/0191-3913-19860901-12.
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Feldmann-Wüstefeld, Tobias, Marina Weinberger, and Edward Awh. "Spatially Guided Distractor Suppression during Visual Search." Journal of Neuroscience 41, no. 14 (March 2, 2021): 3180–91. http://dx.doi.org/10.1523/jneurosci.2418-20.2021.
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Murai, Norihiko, Yasushi Naito, Kazuo Funabiki, Naomi Kato, and Juichi Ito. "Visual Suppression Testing during Manual Sinusoidal Rotation." Equilibrium Research 60, no. 4 (2001): 234–40. http://dx.doi.org/10.3757/jser.60.234.
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Won, Bo-Yeong, and Joy Geng. "Passive Suppression of Distractors in Visual Search." Journal of Vision 19, no. 10 (September 6, 2019): 213b. http://dx.doi.org/10.1167/19.10.213b.
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Smith, M. A. "Surround Suppression in the Early Visual System." Journal of Neuroscience 26, no. 14 (April 5, 2006): 3624–25. http://dx.doi.org/10.1523/jneurosci.0236-06.2006.
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Brouwer, Gijs Joost, and David J. Heeger. "Cross-orientation suppression in human visual cortex." Journal of Neurophysiology 106, no. 5 (November 2011): 2108–19. http://dx.doi.org/10.1152/jn.00540.2011.
Повний текст джерелаАнотація:
Cross-orientation suppression was measured in human primary visual cortex (V1) to test the normalization model. Subjects viewed vertical target gratings (of varying contrasts) with or without a superimposed horizontal mask grating (fixed contrast). We used functional magnetic resonance imaging (fMRI) to measure the activity in each of several hypothetical channels (corresponding to subpopulations of neurons) with different orientation tunings and fit these orientation-selective responses with the normalization model. For the V1 channel maximally tuned to the target orientation, responses increased with target contrast but were suppressed when the horizontal mask was added, evident as a shift in the contrast gain of this channel's responses. For the channel maximally tuned to the mask orientation, a constant baseline response was evoked for all target contrasts when the mask was absent; responses decreased with increasing target contrast when the mask was present. The normalization model provided a good fit to the contrast-response functions with and without the mask. In a control experiment, the target and mask presentations were temporally interleaved, and we found no shift in contrast gain, i.e., no evidence for suppression. We conclude that the normalization model can explain cross-orientation suppression in human visual cortex. The approach adopted here can be applied broadly to infer, simultaneously, the responses of several subpopulations of neurons in the human brain that span particular stimulus or feature spaces, and characterize their interactions. In addition, it allows us to investigate how stimuli are represented by the inferred activity of entire neural populations.
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Balp, Rodrigo, Florian Waszak, and Thérèse Collins. "Visual features of Saccadic Suppression of Displacement." Journal of Vision 17, no. 10 (August 31, 2017): 1161. http://dx.doi.org/10.1167/17.10.1161.
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Center, Evan, Monica Fabiani, Gabriele Gratton, and Diane Beck. "Elucidating Mechanisms of TMS-induced Visual Suppression." Journal of Vision 17, no. 10 (August 31, 2017): 1349. http://dx.doi.org/10.1167/17.10.1349.
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Rucci, Michele, and Naghmeh Mostofi. "Visual suppression within the foveola during microsaccades." Journal of Vision 17, no. 10 (August 31, 2017): 921. http://dx.doi.org/10.1167/17.10.921.
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Wilke, Melanie, Nikos K. Logothetis, and David A. Leopold. "Generalized Flash Suppression of Salient Visual Targets." Neuron 39, no. 6 (September 2003): 1043–52. http://dx.doi.org/10.1016/j.neuron.2003.08.003.
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Vidnyanszky, Z., V. Gal, I. Kobor, L. Kozak, and J. Serences. "Attentional suppression spreads throughout the visual field." Journal of Vision 7, no. 9 (March 23, 2010): 787. http://dx.doi.org/10.1167/7.9.787.
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Hydén, Dag, Birgitta Larsby, Lars M. ödkvist, and Claes Möller. "Visual Suppression Tests in Acoustic Neuroma Patients." Acta Oto-Laryngologica 108, sup468 (January 1989): 349–51. http://dx.doi.org/10.3109/00016488909139075.
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Schlindwein, P., M. Schreckenberger, and M. Dieterich. "Visual-Motion Suppression in Congenital Pendular Nystagmus." Annals of the New York Academy of Sciences 1164, no. 1 (May 2009): 458–60. http://dx.doi.org/10.1111/j.1749-6632.2008.03742.x.
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Scholl, Ben, Xiang Gao, and Michael Wehr. "Level Dependence of Contextual Modulation in Auditory Cortex." Journal of Neurophysiology 99, no. 4 (April 2008): 1616–27. http://dx.doi.org/10.1152/jn.01172.2007.
Повний текст джерелаАнотація:
Responses of cortical neurons to sensory stimuli within their receptive fields can be profoundly altered by the stimulus context. In visual and somatosensory cortex, contextual interactions have been shown to change sign from facilitation to suppression depending on stimulus strength. Contextual modulation of high-contrast stimuli tends to be suppressive, but for low-contrast stimuli tends to be facilitative. This trade-off may optimize contextual integration by cortical cells and has been suggested to be a general feature of cortical processing, but it remains unknown whether a similar phenomenon occurs in auditory cortex. Here we used whole cell and single-unit recordings to investigate how contextual interactions in auditory cortical neurons depend on the relative intensity of masker and probe stimuli in a two-tone stimulus paradigm. We tested the hypothesis that relatively low-level probes should show facilitation, whereas relatively high-level probes should show suppression. We found that contextual interactions were primarily suppressive across all probe levels, and that relatively low-level probes were subject to stronger suppression than high-level probes. These results were virtually identical for spiking and subthreshold responses. This suggests that, unlike visual cortical neurons, auditory cortical neurons show maximal suppression rather than facilitation for relatively weak stimuli.
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Nagata, Takanobu, Akimasa Ishida, Yutaka Fukuoka, and Haruyuki Minamitani. "Role of Visual Feedback in Upright Posture Control." Journal of Robotics and Mechatronics 13, no. 6 (December 20, 2001): 594–600. http://dx.doi.org/10.20965/jrm.2001.p0594.
Повний текст джерелаАнотація:
We studied the role of visual feedback in upright posture control on the sagittal plane. In posture control, each sensory system has the following roles: initial detection of sway, suppression of short-term sway around the equilibrium point, and suppression of longterm sway induced by a slow shift in equilibrium. Experiments were conducted to examine features of each sensor and then visual contribution was studied. Based on measured sensory thresholds for the perception of sway during standing, it was suggested that visual input provided sensitive means of perceiving postural sway. Body sway of a subject was measured under several conditions in which the subject controlled upright posture utilizing the definite number of sensors. By analyzing and comparing measured sway waveforms under each condition, it was clear that the visual system suppressed short-term sway. Spectral analysis showed that the visual system suppressed body sway in a low frequency range around 0.2 Hz. Though visual feedback contains a large time delay, the influence of the delay is small in the low frequency range. It is rational that vision is efficient at suppressing body sway in the low frequency range.
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Tanabe, Seiji, and Bruce G. Cumming. "Delayed suppression shapes disparity selective responses in monkey V1." Journal of Neurophysiology 111, no. 9 (May 1, 2014): 1759–69. http://dx.doi.org/10.1152/jn.00426.2013.
Повний текст джерелаАнотація:
The stereo correspondence problem poses a challenge to visual neurons because localized receptive fields potentially cause false responses. Neurons in the primary visual cortex (V1) partially resolve this problem by combining excitatory and suppressive responses to encode binocular disparity. We explored the time course of this combination in awake, monkey V1 neurons using subspace mapping of receptive fields. The stimulus was a binocular noise pattern constructed from discrete spatial frequency components. We forward correlated the firing of the V1 neuron with the occurrence of binocular presentations of each spatial frequency component. The forward correlation yielded a complete set of response time courses to every combination of spatial frequency and interocular phase difference. Some combinations produced suppressive responses. Typically, if an interocular phase difference for a given spatial frequency produced strong excitation, we saw suppression in response to the opposite interocular phase difference at lower spatial frequencies. The suppression was delayed relative to the excitation, with a median difference in latency of 7 ms. We found that the suppressive mechanism explains a well-known mismatch of monocular and binocular signals. The suppressive components increased power at low spatial frequencies in disparity tuning, whereas they reduced the monocular response to low spatial frequencies. This long-recognized mismatch of binocular and monocular signals reflects a suppressive mechanism that helps reduce the response to false matches.
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Cave, Carolyn Backer, Randolph Blake, and Timothy P. McNamara. "Binocular Rivalry Disrupts Visual Priming." Psychological Science 9, no. 4 (July 1998): 299–302. http://dx.doi.org/10.1111/1467-9280.00059.
Повний текст джерелаАнотація:
Many results implicate perceptual processing in repetition priming, but little is known of potential mechanisms for priming. A new method was used to help determine the processing stage at which priming occurs. Priming pictures were presented under dominance or suppression generated by binocular rivalry. Although low-level, sensory attributes can be processed under rivalry suppression, there is no evidence that repetition priming can be supported by such low-level processing. Priming was found only for stimuli that were processed sufficiently to be identified in the priming stage. The results demonstrate that repetition priming requires processing of stimulus attributes into relatively high-level representations.