Journal articles on the topic 'Loom stimulus'
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1
Spano, Lauren, Skye M. Long, and Elizabeth M. Jakob. "Secondary eyes mediate the response to looming objects in jumping spiders ( Phidippus audax , Salticidae)." Biology Letters 8, no. 6 (October 17, 2012): 949–51. http://dx.doi.org/10.1098/rsbl.2012.0716.
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Some species have sensory systems divided into subsystems with morphologically different sense organs that acquire different types of information within the same modality. Jumping spiders (family Salticidae) have eight eyes. Four eyes are directed anteriorly to view objects in front of the spider: a pair of principal eyes track targets with their movable retinae, while the immobile anterior lateral (AL) eyes have a larger field of view and lower resolution. To test whether the principal eyes, the AL eyes, or both together mediate the response to looming stimuli, we presented spiders with a video of a solid black circle that rapidly expanded (loomed) or contracted (receded). Control spiders and spiders with their principal eyes masked were significantly more likely to back away from the looming stimulus than were spiders with their AL eyes masked. Almost no individuals backed away from the receding stimulus. Our results show that the AL eyes alone mediate the loom response to objects anterior to the spider.
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Santer, Roger D., F. Claire Rind, Richard Stafford, and Peter J. Simmons. "Role of an Identified Looming-Sensitive Neuron in Triggering a Flying Locust's Escape." Journal of Neurophysiology 95, no. 6 (June 2006): 3391–400. http://dx.doi.org/10.1152/jn.00024.2006.
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Flying locusts perform a characteristic gliding dive in response to predator-sized stimuli looming from one side. These visual looming stimuli trigger trains of spikes in the descending contralateral movement detector (DCMD) neuron that increase in frequency as the stimulus gets nearer. Here we provide evidence that high-frequency (>150 Hz) DCMD spikes are involved in triggering the glide: the DCMD is the only excitatory input to a key gliding motor neuron during a loom; DCMD-mediated EPSPs only summate significantly in this motor neuron when they occur at >150 Hz; when a looming stimulus ceases approach prematurely, high-frequency DCMD spikes are removed from its response and the occurrence of gliding is reduced; and an axon important for glide triggering descends in the nerve cord contralateral to the eye detecting a looming stimulus, as the DCMD does. DCMD recordings from tethered flying locusts showed that glides follow high-frequency spikes in a DCMD, but analyses could not identify a feature of the DCMD response alone that was reliably associated with glides in all trials. This was because, for a glide to be triggered, the high-frequency spikes must be timed appropriately within the wingbeat cycle to coincide with wing elevation. We interpret this as flight-gating of the DCMD response resulting from rhythmic modulation of the flight motor neuron's membrane potential during flight. This means that the locust's escape behavior can vary in response to the same looming stimulus, meaning that a predator cannot exploit predictability in the locust's collision avoidance behavior.
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Lopez-Paniagua, Dan, and Carol A. Seger. "Interactions within and between Corticostriatal Loops during Component Processes of Category Learning." Journal of Cognitive Neuroscience 23, no. 10 (October 2011): 3068–83. http://dx.doi.org/10.1162/jocn_a_00008.
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We examined dynamic interactions between cortex and BG during stimulus–response and feedback processing phases of categorization. First, we dissociated stimulus–response processing from feedback processing using “jittered” intervals of time between response and feedback to examine how each recruits the four primary corticostriatal loops (motor, executive, visual, and motivational). Second, we examined dynamic interactions within and between corticostriatal loops using Granger causality mapping. On each trial, subjects viewed one of six abstract visual stimuli, pressed a button indicating category membership, and then received feedback as to whether the decision was right or wrong. Stimulus–response processing was associated with greater activity in the visual loop, whereas feedback processing resulted in activity in the executive loop that was sensitive to feedback valence. Granger causality mapping showed patterns of directed influence within corticostriatal loops and between loops from the motor to the executive, to the visual, and finally to the motivational loop. These patterns of interaction are consistent with functional integration of motor processing in the motor loop with feedback processing in the executive loop and maintenance of stimulus–response history for future responses in the motivational loop.
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Preciado, Daniel, and Jan Theeuwes. "To look or not to look? Reward, selection history, and oculomotor guidance." Journal of Neurophysiology 120, no. 4 (October 1, 2018): 1740–52. http://dx.doi.org/10.1152/jn.00275.2018.
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The current eye-tracking study examined the influence of reward on oculomotor performance, and the extent to which learned stimulus-reward associations interacted with voluntary oculomotor control with a modified paradigm based on the classical antisaccade task. Participants were shown two equally salient stimuli simultaneously: a gray and a colored circle, and they were instructed to make a fast saccade to one of them. During the first phase of the experiment, participants made a fast saccade toward the colored stimulus, and their performance determined a (cash) bonus. During the second, participants made a saccade toward the gray stimulus, with no rewards available. On each trial, one of three colors was presented, each associated with high, low or no reward during the first phase. Results from the first phase showed improved accuracy and shorter saccade latencies on high-reward trials, while those from the second replicated well-known effects typical of the antisaccade task, namely, decreased accuracy and increased latency during phase II, even despite the absence of abrupt asymmetric onsets. Crucially, performance differences between phases revealed longer latencies and less accurate saccades during the second phase for high-reward trials, compared with the low- and no-reward trials. Further analyses indicated that oculomotor capture by reward signals is mainly found for saccades with short latencies, while this automatic capture can be overridden through voluntary control with longer ones. These results highlight the natural flexibility and adaptability of the attentional system, and the role of reward in modulating this plasticity. NEW & NOTEWORTHY Typically, in the antisaccade task, participants need to suppress an automatic orienting reflex toward a suddenly appearing peripheral stimulus. Here, we introduce an alternative antisaccade task without such abrupt onsets. We replicate well-known antisaccade effects (more errors and longer latencies), demonstrating the role of reward in developing selective oculomotor biases. Results highlight how reward and selection history facilitate developing automatic biases from goal-driven behavior, and they suggest that this process responds to individual differences in impulsivity.
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Tuma, R. S. "Stimulus Funds Force Hard Look at Comparative Effectiveness Research." JNCI Journal of the National Cancer Institute 101, no. 15 (July 28, 2009): 1036–39. http://dx.doi.org/10.1093/jnci/djp242.
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Fox, Jeffrey L. "Healthcare reform looms, firms seek scraps from US stimulus." Nature Biotechnology 27, no. 5 (May 2009): 406–7. http://dx.doi.org/10.1038/nbt0509-406.
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Karlsen, Elizabeth A., C. W. Norris, and Ruth S. Hassanein. "The Effect of Stimulus Duration Using the Brookler-Grams Closed-Loop Caloric Irrigator." Journal of Speech, Language, and Hearing Research 35, no. 3 (June 1992): 718–19. http://dx.doi.org/10.1044/jshr.3503.718.
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Nystagmic responses to traditional 40-sec, 30 °C water calorics were recorded and compared to those obtained with the Brookler-Grams closed-loop irrigator using 30 °C, 40-, 50-, and 60-sec irrigations. Significant differences were noted between the responses to the water irrigator and the 40- and 50-sec closed-loop irrigations. The 60-sec closed-loop irrigation produced responses that were equivalent to the responses obtained with the water irrigation in slow component velocity, amplitude, frequency, latency, and duration. The 30 °C 60-sec closed-loop irrigation is an acceptable stimulus in electronystagmographic caloric testing.
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Mearns, Duncan S., Joseph C. Donovan, António M. Fernandes, Julia L. Semmelhack, and Herwig Baier. "Deconstructing Hunting Behavior Reveals a Tightly Coupled Stimulus-Response Loop." Current Biology 30, no. 1 (January 2020): 54–69. http://dx.doi.org/10.1016/j.cub.2019.11.022.
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Kittmann, R. "Neural mechanisms of adaptive gain control in a joint control loop: muscle force and motoneuronal activity." Journal of Experimental Biology 200, no. 9 (January 1, 1997): 1383–402. http://dx.doi.org/10.1242/jeb.200.9.1383.
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An adaptive gain control system of a proprioceptive feedback system, the femur­tibia control loop, is investigated. It enables the joint control loop to work with a high gain but it prevents instability oscillations. In the inactive stick insect, the realisation of specific changes in gain is described for tibial torque, for extensor tibiae muscle force and for motoneuronal activity. In open-loop experiments, sinusoidal stimuli are applied to the femoral chordotonal organ (fCO). Changes in gain that depend on fCO stimulus parameters (such as amplitude, frequency and repetition rate), are investigated. Furthermore, spontaneous and touch-induced changes in gain that resemble the behavioural state of the animal are described. Changes in gain in motoneurones are always realised as changes in the amplitude of modulation of their discharge frequency. Nevertheless, depending on the stimulus situation, two different mechanisms underlie gain changes in motoneurones. (i) Changes in gain can be based on changes in the strength of the sensorimotor pathways that transmit stimulus-modulated information from the fCO to the motoneurones. (ii) Changes in gain can be based on changes in the mean activity of a motoneurone by means of its spike threshold: when, during the modulation, the discharge of a motoneurone is inhibited for part of the stimulus cycle, then a change in mean activity subsequently causes a change in modulation amplitude and gain. A new neuronal mechanism is described that helps to compensate the low-pass filter characteristics of the muscles by an increased activation, especially by a sharper distribution of spikes in the stimulus cycle at high fCO stimulus frequencies.
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Ford, Kristen A., Herbert C. Goltz, Matthew R. G. Brown, and Stefan Everling. "Neural Processes Associated With Antisaccade Task Performance Investigated With Event-Related fMRI." Journal of Neurophysiology 94, no. 1 (July 2005): 429–40. http://dx.doi.org/10.1152/jn.00471.2004.
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One of the hallmarks of cognitive control is the suppression of prepotent but inappropriate responses. Here we used event-related functional MRI to measure functional brain activation during a stimulus-response incompatibility task. Subjects were instructed before a stimulus appeared either to look at the stimulus (prosaccade) or to look away from the stimulus (antisaccade). Eye movements were recorded so that functional brain activation could be grouped into prosaccades, correct antisaccades, and errors (saccades toward the stimulus on antisaccade trials). Correct antisaccade trials were associated with significantly more activation in frontal and parietal cortical areas compared with prosaccade trials during the late preparatory period before stimulus appearance. Correct antisaccades evoked more activation than errors in the right dorsolateral prefrontal cortex, anterior cingulate cortex (ACC), and presupplementary eye fields during this period. No significant differences were found for any comparisons early in the preparatory period. Our data suggest that the preparation of an antisaccade activates a large frontal and parietal network that may be involved in presetting the oculomotor system for the antisaccade task. These findings indicate that a large network of frontal and posterior areas is modulated during the latter component of the preparatory period on antisaccade compared with prosaccade trials. The results further suggest that the activation level of frontal cortical areas before stimulus presentation is associated with subjects' performance in the antisaccade task. In contrast, we found no areas that were more active for correct antisaccades than prosaccades or for correct antisaccades than error antisaccades during the stimulus-response period. In fact, a number of posterior cortical areas and a few areas in the superior frontal lobe were more active during the stimulus-response period on prosaccade trials than on antisaccade trials. Error antisaccades showed a larger activation in the ACC during the stimulus-response period compared with correct antisaccades.
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Strauss, R., S. Schuster, and K. G. Götz. "Processing of artificial visual feedback in the walking fruit fly Drosophila melanogaster." Journal of Experimental Biology 200, no. 9 (May 1, 1997): 1281–96. http://dx.doi.org/10.1242/jeb.200.9.1281.
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A computerized 360 degrees panorama allowed us to suppress most of the locomotion-induced visual feedback of a freely walking fly without neutralizing its mechanosensory system ('virtual open-loop' conditions). This novel paradigm achieves control over the fly's visual input by continuously evaluating its actual position and orientation. In experiments with natural visual feedback (closed-loop conditions), the optomotor turning induced by horizontal pattern motion in freely walking Drosophila melanogaster increased with the contrast and brightness of the stimulus. Conspicuously striped patterns were followed with variable speed but often without significant overall slippage. Using standard open-loop conditions in stationary walking flies and virtual open-loop or closed-loop conditions in freely walking flies, we compared horizontal turning induced by either horizontal or vertical motion of appropriately oriented rhombic figures. We found (i) that horizontal displacements and the horizontal-motion illusion induced by vertical displacements of the oblique edges of the rhombic figures elicited equivalent open-loop turning responses; (ii) that locomotion-induced visual feedback from the vertical edges of the rhombic figures in a stationary horizontal position diminished the closed-loop turning elicited by vertical displacements to only one-fifth of the response to horizontal displacements; and (iii) that virtual open-loop responses of mobile flies and open-loop responses of immobilized flies were equivalent in spite of delays of up to 0.1 s in the generation of the virtual stimulus. Horizontal compensatory turning upon vertical displacements of oblique edges is quantitatively consistent with the direction-selective summation of signals from an array of elementary motion detectors for the horizontal stimulus components within their narrow receptive fields. A compensation of the aperture-induced ambiguity can be excluded under these conditions. However, locomotion-induced visual feedback greatly diminished the horizontal-motion illusion in a freely walking fly. The illusion was used to assay the quality of open-loop simulation in the new paradigm.
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Zuber, Irena, and Bo Ekehammar. "An empirical look at the Defence Mechanism Test (DMT) Stimulus effects." Scandinavian Journal of Psychology 38, no. 2 (June 1997): 85–94. http://dx.doi.org/10.1111/1467-9450.00013.
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Mervis, J. "Stimulus Spending Looms Large as Obama Charts a Course for Science." Science 324, no. 5929 (May 14, 2009): 864–66. http://dx.doi.org/10.1126/science.324_864a.
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Watanabe, Masayuki, and Douglas P. Munoz. "Saccade Reaction Times Are Influenced by Caudate Microstimulation Following and Prior to Visual Stimulus Appearance." Journal of Cognitive Neuroscience 23, no. 7 (July 2011): 1794–807. http://dx.doi.org/10.1162/jocn.2010.21554.
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Several cognitive models suggest that saccade RTs are controlled flexibly not only by mechanisms that accumulate sensory evidence after the appearance of a sensory stimulus (poststimulus mechanisms) but also by mechanisms that preset the saccade control system before the sensory event (prestimulus mechanisms). Consistent with model predictions, neurons in structures tightly related to saccade initiation, such as the superior colliculus and FEF, have poststimulus and prestimulus activities correlated with RTs. It has been hypothesized that the BG influence the saccade initiation process by controlling both poststimulus and prestimulus activities of superior colliculus and FEF neurons. To examine this hypothesis directly, we delivered electrical microstimulation to the caudate nucleus, the input stage of the oculomotor BG, while monkeys performed a prosaccade (look toward a visual stimulus) and antisaccade (look away from the stimulus) paradigm. Microstimulation applied after stimulus appearance (poststimulus microstimulation) prolonged RTs regardless of saccade directions (contra/ipsi) or task instructions (pro/anti). In contrast, microstimulation applied before stimulus appearance (prestimulus microstimulation) shortened RTs, although the effects were limited to several task conditions. The analysis of RT distributions using the linear approach to threshold with ergodic rate model revealed that poststimulus microstimulation prolonged RTs by reducing the rate of rise to the threshold for saccade initiation, whereas fitting results for prestimulus microstimulation were inconsistent across different task conditions. We conclude that both poststimulus and prestimulus activities of caudate neurons are sufficient to control saccade RTs.
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Yi, Do-Joon, Nicholas B. Turk-Browne, Marvin M. Chun, and Marcia K. Johnson. "When a Thought Equals a Look: Refreshing Enhances Perceptual Memory." Journal of Cognitive Neuroscience 20, no. 8 (August 2008): 1371–80. http://dx.doi.org/10.1162/jocn.2008.20094.
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Cognition constantly involves retrieving and maintaining information that is not perceptually available in the current environment. Studies on visual imagery and working memory suggest that such high-level cognition might, in part, be mediated by the revival of perceptual representations in the inferior temporal cortex. Here, we provide new support for this hypothesis, showing that reflectively accessed information can have similar consequences for subsequent perception as actual perceptual input. Participants were presented with pairs of frames in which a scene could appear, and were required to make a category judgment on the second frame. In the critical condition, a scene was presented in the first frame, but the second frame was blank. Thus, it was necessary to refresh the scene from the first frame in order to make the category judgment. Scenes were then repeated in subsequent trials to measure the effect of refreshing on functional magnetic resonance imaging repetition attenuation—a neural index of memory—in a scene-selective region of the visual cortex. Surprisingly, the refreshed scenes produced equal attenuation as scenes that had been presented twice during encoding, and more attenuation than scenes that had been presented once during encoding, but that were not refreshed. Thus, the top-down revival of a percept had a similar effect on memory as actually seeing the stimulus again. These findings indicate that high-level cognition can activate stimulus-specific representations in the ventral visual cortex, and that such top-down activation, like that from sensory stimulation, produces memorial changes that affect perceptual processing during a later encounter with the stimulus.
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Jorjafki, Elham Mohammadi, Brad J. Sagarin, and Sachit Butail. "Drawing power of virtual crowds." Journal of The Royal Society Interface 15, no. 145 (August 2018): 20180335. http://dx.doi.org/10.1098/rsif.2018.0335.
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In 1969, social psychologist Milgram and his colleagues conducted an experiment on a busy city street where passers-by witnessed a set of actors spontaneously looking up towards a building. The experiment showed that the crowd's propensity to mimic the actor's gaze increased with the number of actors that looked up. This form of behavioural contagion is found in many social organisms and is central to how information travels through large groups. With the advancement of virtual reality and its continued application towards understanding human response to crowd behaviour, it remains to be verified if behavioural contagion occurs in walkable virtual environments, and how it compares with results from real-world experiments. In this study, we adapt Milgram's experiment for virtual environments and use it to reproduce behavioural contagion. Specifically, we construct a replica of an indoor location and combine two established pedestrian motion models to create an interactive crowd of 60 virtual characters that walk through the indoor location. The stimulus group comprised a subset of the characters who look up at a random time as the participants explore the virtual environment. Our results show that the probability of looking up by a participant is dependent on the size of the stimulus group saturating to near certainty when three or more characters look up. The role of stimulus size was also evident when participant actions were compared with survey responses which showed that more participants selected to not look up even though they saw characters redirect their gaze upwards when the size of the stimulus group was small. Participants also spent more time looking up and exhibited frequent head turns with a larger stimulus group. Results from this study provide evidence that behavioural contagion can be triggered in the virtual environment, and can be used to build and test complex hypotheses for understanding human behaviour in a variety of crowd scenarios.
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Edin, Fredrik, Christian K. Machens, Hartmut Schütze, and Fredrik Edin. "Searching for Optimal Sensory Signals: Iterative Stimulus Reconstruction in Closed-Loop Experiments." Journal of Computational Neuroscience 17, no. 1 (July 2004): 47–56. http://dx.doi.org/10.1023/b:jcns.0000023868.18446.a2.
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Lee, B. B., and J. Kremers. "A New Look at Primate Ganglion Cell Receptive Field Structure." Perception 26, no. 1_suppl (August 1997): 231. http://dx.doi.org/10.1068/v970184.
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We have reinvestigated receptive field structure of macaque ganglion cells using a novel stimulus—counterphase modulation of a bipartite field—with luminance, chromatic, or cone-selective stimulation. We previously used this stimulus (Kremers et al, 1995 Colour Vision DeficienciesXII 399 – 406) to show that surrounds of middle (M) and long (L) wavelength cone opponent cells of the parvocellular (PC) pathway are cone specific, measuring on a finer scale than in previous experiments [Reid and Shapley, 1992 Nature (London)356 716 – 718]. Modelling of response amplitude and phase now confirms this conclusion. Second, centre sizes measured were consistent with those from the literature, with PC and magnocellular pathway (MC) cell centres having similar size. Modelling on the basis of single cone centres for PC-cells plus optical blur provided a partial description of the data, but some inconsistencies were present. Last, the chromatic nonlinearity of magnocellular pathway ganglion cells appears to result from a subunit structure within the receptive-field surround.
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Bestmann, Hans Jürgen, Joachim Erler, and Otto Vostrowsky. "Bestimmung der relativen Flüchtigkeit von Sexualpheromonen von Schmetterlingen mittels Closed Loop Stripping* / Determination of Relative Volatility of Lepidoptera Sex Pheromones by Closed Loop Stripping." Zeitschrift für Naturforschung C 45, no. 6 (June 1, 1990): 698–702. http://dx.doi.org/10.1515/znc-1990-0621.
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Abstract By means of closed loop Stripping the relative evaporation rates of monounsaturated C10-C16-acetates and C10-C12-alcohols have been determined. The results of stimulus released demonstrate the different volatilities of pheromone compounds which should be taken in account with certain biotests and physiological studies.
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YOUNG, STEPHEN, and VICTORIA A. TAYLOR. "Spontaneous and Evoked Eye Movements in Polyphemus Pediculus (Cladocera: Crustacea): A Case of Open-Loop Tracking?" Journal of Experimental Biology 131, no. 1 (September 1, 1987): 323–36. http://dx.doi.org/10.1242/jeb.131.1.323.
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1. Polyphemus eye movements were recorded in both pitching and yawing planes, both in a static visual environment and with a sinusoidally moving stimulus. 2. Spontaneous eye movements (average amplitude 1.7°) had different properties in the two planes, with trembling movements predominating in the pitching plane. A contour-sharpening function is proposed for these movements. 3. An attempt to analyse the eye movement response system using a Bode diagram shows a very poor fit to the data, leading to the conclusion that a closed-loop control system is an inappropriate model in this case. 4. The evoked eye movements are most convincingly represented by a model in which the time the stimulus takes to traverse a restricted sensitive zone in the central region of the eye controls the duration of a subsequent constant angular velocity saccade. The direction of the response movement follows the direction of the stimulus. A small-object tracking function is proposed for these movements.
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Fisk, Arthur D., and Mark M. Eboch. "Applications of Automatic/Control Processing Theory to Complex Tasks: An Encouraging Look." Proceedings of the Human Factors Society Annual Meeting 31, no. 6 (September 1987): 674–78. http://dx.doi.org/10.1177/154193128703100614.
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This paper briefly outlines experiments that point to where and how automatic/control processing theory can be applied to complex training simulations of “real world” tasks. In all of these complex tasks, subjects could not simply focus in on a single stimulus and successfully perform the task. Rather, subjects were required to process combinations of stimuli for successful task completion. The pattern of data from these complex tasks is consistent with previous data collected using simple, stimulus-specific tasks. This similarity between results of previous research examining automatic/control processing and the present data points to the validity of suggesting the need for consistent mapping training of patterns of information in complex tasks. Preliminary applications of automatic/ control processing theory to instructional design and to cartography are discussed.
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Mütze, Hanna, Reinhard Kopiez, and Anna Wolf. "The effect of a rhythmic pulse on the heart rate: Little evidence for rhythmical ‘entrainment’ and ‘synchronization’." Musicae Scientiae 24, no. 3 (December 18, 2018): 377–400. http://dx.doi.org/10.1177/1029864918817805.
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In this study, we investigate the influence of musical tempo on the heart rate. Previous studies showed ambiguous results. Two effects are considered: first, an adaption of the heart rate frequency to the tempo of a musical stimulus (‘entrainment’) and second, the phase synchronization between the stimulus-onset and the R-waves in the ECG (‘synchronization’). A regulatory feedback loop was programmed, which constantly measured the actual heart rate. A simple Djembé-beat was used as a musical stimulus and coupled to the actual heart rate in real-time. To test for ‘entrainment’ effects, we adapted the tempo of the stimulus in real-time to the actual heart rate by increasing the rate 25%, 40% or 55% over the baseline tempo. To test for ‘synchronization’ effects, we presented the stimulus in a constant tempo, tracking the actual heart rate of the test person. Based on circular statistics, results showed no evidence for ‘entrainment’ or ‘synchronization’ effects of the stimulus on the heart rate. Overall, reactions to the trigger pulse were characterized by a high degree of interindividual differences. Thus, we conclude that there is no direct and simple correlation between the musical tempo and the HR contrary to what is often suggested in everyday psychology.
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Coe, Brian C., and Douglas P. Munoz. "Mechanisms of saccade suppression revealed in the anti-saccade task." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1718 (February 27, 2017): 20160192. http://dx.doi.org/10.1098/rstb.2016.0192.
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The anti-saccade task has emerged as an important tool for investigating the complex nature of voluntary behaviour. In this task, participants are instructed to suppress the natural response to look at a peripheral visual stimulus and look in the opposite direction instead. Analysis of saccadic reaction times (SRT: the time from stimulus appearance to the first saccade) and the frequency of direction errors (i.e. looking toward the stimulus) provide insight into saccade suppression mechanisms in the brain. Some direction errors are reflexive responses with very short SRTs (express latency saccades), while other direction errors are driven by automated responses and have longer SRTs. These different types of errors reveal that the anti-saccade task requires different forms of suppression, and neurophysiological experiments in macaques have revealed several potential mechanisms. At the start of an anti-saccade trial, pre-emptive top-down inhibition of saccade generating neurons in the frontal eye fields and superior colliculus must be present before the stimulus appears to prevent express latency direction errors. After the stimulus appears, voluntary anti-saccade commands must compete with, and override, automated visually initiated saccade commands to prevent longer latency direction errors. The frequencies of these types of direction errors, as well as SRTs, change throughout the lifespan and reveal time courses for development, maturation, and ageing. Additionally, patients diagnosed with a variety of neurological and/or psychiatric disorders affecting the frontal lobes and/or basal ganglia produce markedly different SRT distributions and types of direction errors, which highlight specific deficits in saccade suppression and inhibitory control. The anti-saccade task therefore provides valuable insight into the neural mechanisms of saccade suppression and is a valuable tool in a clinical setting. This article is part of the themed issue ‘Movement suppression: brain mechanisms for stopping and stillness’.
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Mendrysa, Susan M., and Mary Ellen Perry. "The p53 Tumor Suppressor Protein Does Not Regulate Expression of Its Own Inhibitor, MDM2, Except under Conditions of Stress." Molecular and Cellular Biology 20, no. 6 (March 15, 2000): 2023–30. http://dx.doi.org/10.1128/mcb.20.6.2023-2030.2000.
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ABSTRACT MDM2 is an important regulator of the p53 tumor suppressor protein. MDM2 inhibits p53 by binding to it, physically blocking its ability to transactivate gene expression, and stimulating its degradation. In cultured cells, mdm2 expression can be regulated by p53. Hence, mdm2 and p53 can interact to form an autoregulatory loop in which p53 activates expression of its own inhibitor. The p53/MDM2 autoregulatory loop has been elucidated within cultured cells; however, regulation of mdm2 expression by p53 has not been demonstrated within intact tissues. Here, we examine the role of p53 in regulating mdm2 expression in vivo in order to test the hypothesis that the p53/MDM2 autoregulatory loop is the mechanism by which low levels of p53 are maintained. We demonstrate that basal expression of mdm2 in murine tissues is p53 independent, even in tissues that express functional p53. Transcription ofmdm2 is induced in a p53-dependent manner following gamma irradiation, indicating that p53 regulates mdm2 expression in vivo following a stimulus. The requirement for a stimulus to activate p53-dependent regulation of mdm2 expression in vivo appeared to differ from the situation in early-passage mouse embryo fibroblasts, where mdm2 expression is enhanced by the presence of p53. Analysis of mdm2 expression in intact and dispersed embryos revealed that establishment of mouse embryo fibroblasts in culture induces p53-dependent mdm2expression, suggesting that an unknown stimulus activates p53 function in cultured cells. Together, these results indicate that p53 does not regulate expression of its own inhibitor, except in response to stimuli.
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Poon, C. S. "Estimation of response curves in closed-loop physiological control." Journal of Applied Physiology 61, no. 4 (October 1, 1986): 1481–91. http://dx.doi.org/10.1152/jappl.1986.61.4.1481.
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Several recent reports have addressed the problem of estimating the response slope from repeated measurements of paired data when both stimulus and response variables are subject to biological variability. These earlier approaches suffer from several drawbacks: useful information about the relationships between the error components in a closed-loop system is not fully utilized; the response intercept cannot be directly estimated; and the normalization procedure required in some methods may fail under certain circumstances. This paper proposes a new, general method of simultaneously estimating the response slope and intercept from corrupted stimulus-response data when the errors in both variables are specifically related by the system structure. A direct extension of the least-squares approach, this method [directed least squares (DLS)] reduces to ordinary least-squares methods when either of the measured variables is error free and to the reduced-major-axis (RMA) method of Kermack and Haldane (Biometrics 37: 30-41, 1950) when the magnitudes of the normalized errors are equal. The DLS estimators are scale invariant, statistically unbiased and always assume the minimum variance. With simple modifications, the method is also applicable to paired data. If, however, the relation between error components is uncertain, then the RMA method is optimal, i.e., having the least possible asymptotic bias and variance. These results are illustrated by using various types of closed-loop respiratory response data.
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Noorsal, Emilia, Saharul Arof, Saiful Zaimy Yahaya, Zakaria Hussain, Daniel Kho, and Yusnita Mohd Ali. "Design of an FPGA-Based Fuzzy Feedback Controller for Closed-Loop FES in Knee Joint Model." Micromachines 12, no. 8 (August 16, 2021): 968. http://dx.doi.org/10.3390/mi12080968.
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Functional electrical stimulation (FES) device has been widely used by spinal cord injury (SCI) patients in their rehab exercises to restore motor function to their paralysed muscles. The major challenge of muscle contraction induced by FES is early muscle fatigue due to the open-loop stimulation strategy. To reduce the early muscle fatigue phenomenon, a closed-loop FES system is proposed to track the angle of the limb’s movement and provide an accurate amount of charge according to the desired reference angle. Among the existing feedback controllers, fuzzy logic controller (FLC) has been found to exhibit good control performance in handling complex non-linear systems without developing any complex mathematical model. Recently, there has been considerable interest in the implementation of FLC in hardware embedded systems. Therefore, in this paper, a digital fuzzy feedback controller (FFC) embedded in a field-programmable gate array (FPGA) board was proposed. The digital FFC mainly consists of an analog-to-digital converter (ADC) Data Acquisition and FLC sub-modules. The FFC was designed to monitor and control the progress of knee extension movement by regulating the stimulus pulse width duration to meet the target angle. The knee is expected to extend to a maximum reference angle setting (70°, 40° or 30°) from its normal position of 0° once the stimulus charge is applied to the muscle by the FES device. Initially, the FLC was modelled using MATLAB Simulink. Then, the FLC was hardcoded into digital logic using hardware description language (HDL) Verilog codes. Thereafter, the performance of the digital FLC was tested with a knee extension model using the HDL co-simulation technique in MATLAB Simulink. Finally, for real-time verification, the designed digital FFC was downloaded to the Intel FPGA (DE2-115) board. The digital FFC utilized only 4% of the total FPGA (Cyclone IV E) logic elements (LEs) and required 238 µs to regulate stimulus pulse width data, including 3 µs for the FLC computation. The high processing speed of the digital FFC enables the stimulus pulse width duration to be updated every stimulation cycle. Furthermore, the implemented digital FFC has demonstrated good control performance in accurately controlling the stimulus pulse width duration to reach the desired reference angle with very small overshoot (1.4°) and steady-state error (0.4°). These promising results are very useful for a real-world closed-loop FES application.
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Everling, Stefan, and Joseph F. X. DeSouza. "Rule-dependent Activity for Prosaccades and Antisaccades in the Primate Prefrontal Cortex." Journal of Cognitive Neuroscience 17, no. 9 (September 2005): 1483–96. http://dx.doi.org/10.1162/0898929054985455.
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Everyday life typically requires behavior that involves far more than simple stimulus-response associations. Environmental cues are often ambiguous and require different actions depending on the situation. The prefrontal cortex (PFC) is thought to be crucial for this flexible control of behavior. An important task that probes this ability is the antisaccade task in which subjects have to suppress a glance towards a suddenly presented peripheral stimulus and instead look away from the stimulus to its mirror location. Here we recorded the activity of PFC neurons in monkeys trained to alternate between blocks of prosaccade and antisaccade trials with no external instruction cues. We found that the activity of many neurons was different between the two tasks during the fixation period before the peripheral stimulus was presented. These differences were already present on the first correct trials after a task switch. The activity of these neurons also discriminated between correct responses and errors. We hypothesize that the PFC provides bias signals to saccade-related areas that are necessary to preset the oculomotor system for different tasks.
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KITTMANN, ROLF. "GAIN CONTROL IN THE FEMUR-TIBIA FEEDBACK SYSTEM OF THE STICK INSECT." Journal of Experimental Biology 157, no. 1 (May 1, 1991): 503–22. http://dx.doi.org/10.1242/jeb.157.1.503.
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This paper presents a quantitative description of the variability and the adaptive properties of information processing in the femur-tibia feedback system of the stick insect. The gain of this proprioceptive feedback system is determined by external stimuli changing the behavioural state of the animal and by internal properties that make it dependent on different parameters of the stimulus programme, e.g. stimulus frequency and amplitude, repetition rate and resting pauses. The gain of the feedback loop in the inactive animal was investigated under open-loop conditions by applying mechanical sine-wave stimuli to the femoral chordotonal organ (fCO). The resistance movement of the tibia caused by these stimuli was measured with a new optoelectronic device. A large increase or decrease in gain (up to a factor of 50) can be induced by stimulation, but also occurs spontaneously. The system shows habituation and sensitization. The initial gain can be decreased by repetitive sine-wave stimulation of the fCO. Disturbance of the animal (e.g. by tactile stimuli) increases the gain. The gain of the system decreases with increasing stimulus amplitude. The described nonlinearities form a system which adjusts gain to a value that permits effective feedback and prevents instability. This was verified by closedloop experiments. Note: Present address: Institut fur Zoologie II, Friedrich-Alexander-Universitat, Staudtstrasse 5, D-8520 Erlangen, Germany.
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Rohmah, Rina Ari, Purwantoro Purwantoro, and Erni Rouza. "PROGRAM KEMITRAAN MASYARAKAT STIMULUS UMKM MARNING DI DESA MASDA MAKMUR." PAMBUDI 3, no. 2 (December 26, 2019): 75–80. http://dx.doi.org/10.33503/pambudi.v3i2.592.
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The Stimulus Community Partnership Program ( PKMS ) was implemented at the UMKM Marning Mbok Jas. In this stimulant community partnership program there are three efforts to solve the problems faced by partners, namely the first increase in the ability of science and technology in the production system, this effort is made to increase production productivity, optimize production and improve hygienic marning quality. The second effort is to increase the variant of the production of processed corn and corn marning; it aims to increase the variant of corn marning products, namely to increase the variant of corn marning flavor. By creating a third effort which is to change the marketing strategy by creating a taste that consumers like and a consistent taste, making brochures, and labeling it to look attractive and other marketing activities and marketing in the marketplace.
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Choi, Sang Ho, Heenam Yoon, Hyung Won Jin, Hyun Bin Kwon, Seong Min Oh, Yu Jin Lee, and Kwang Suk Park. "Effect of Closed-Loop Vibration Stimulation on Heart Rhythm during Naps." Sensors 19, no. 19 (September 24, 2019): 4136. http://dx.doi.org/10.3390/s19194136.
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Sleep plays a primary function for health and sustains physical and cognitive performance. Although various stimulation systems for enhancing sleep have been developed, they are difficult to use on a long-term basis. This paper proposes a novel stimulation system and confirms its feasibility for sleep. Specifically, in this study, a closed-loop vibration stimulation system that detects the heart rate (HR) and applies −n% stimulus beats per minute (BPM) computed on the basis of the previous 5 min of HR data was developed. Ten subjects participated in the evaluation experiment, in which they took a nap for approximately 90 min. The experiment comprised one baseline and three stimulation conditions. HR variability analysis showed that the normalized low frequency (LF) and LF/high frequency (HF) parameters significantly decreased compared to the baseline condition, while the normalized HF parameter significantly increased under the −3% stimulation condition. In addition, the HR density around the stimulus BPM significantly increased under the −3% stimulation condition. The results confirm that the proposed stimulation system could influence heart rhythm and stabilize the autonomic nervous system. This study thus provides a new stimulation approach to enhance the quality of sleep and has the potential for enhancing health levels through sleep manipulation.
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DeFelice, Mialy M., Helen R. Clark, Jacob J. Hughey, Inbal Maayan, Takamasa Kudo, Miriam V. Gutschow, Markus W. Covert, and Sergi Regot. "NF-κB signaling dynamics is controlled by a dose-sensing autoregulatory loop." Science Signaling 12, no. 579 (April 30, 2019): eaau3568. http://dx.doi.org/10.1126/scisignal.aau3568.
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Over the last decade, multiple studies have shown that signaling proteins activated in different temporal patterns, such as oscillatory, transient, and sustained, can result in distinct gene expression patterns or cell fates. However, the molecular events that ensure appropriate stimulus- and dose-dependent dynamics are not often understood and are difficult to investigate. Here, we used single-cell analysis to dissect the mechanisms underlying the stimulus- and dose-encoding patterns in the innate immune signaling network. We found that Toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling dynamics relied on a dose-dependent, autoinhibitory loop that rendered cells refractory to further stimulation. Using inducible gene expression and optogenetics to perturb the network at different levels, we identified IL-1R–associated kinase 1 (IRAK1) as the dose-sensing node responsible for limiting signal flow during the innate immune response. Although the kinase activity of IRAK1 was not required for signal propagation, it played a critical role in inhibiting the nucleocytoplasmic oscillations of the transcription factor NF-κB. Thus, protein activities that may be “dispensable” from a topological perspective can nevertheless be essential in shaping the dynamic response to the external environment.
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Atherton, Ryan P., Quin M. Chrobak, Frances H. Rauscher, Aaron T. Karst, Matt D. Hanson, Steven W. Steinert, and Kyra L. Bowe. "Shared Processing of Language and Music." Experimental Psychology 65, no. 1 (January 2018): 40–48. http://dx.doi.org/10.1027/1618-3169/a000388.
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Abstract. The present study sought to explore whether musical information is processed by the phonological loop component of the working memory model of immediate memory. Original instantiations of this model primarily focused on the processing of linguistic information. However, the model was less clear about how acoustic information lacking phonological qualities is actively processed. Although previous research has generally supported shared processing of phonological and musical information, these studies were limited as a result of a number of methodological concerns (e.g., the use of simple tones as musical stimuli). In order to further investigate this issue, an auditory interference task was employed. Specifically, participants heard an initial stimulus (musical or linguistic) followed by an intervening stimulus (musical, linguistic, or silence) and were then asked to indicate whether a final test stimulus was the same as or different from the initial stimulus. Results indicated that mismatched interference conditions (i.e., musical – linguistic; linguistic – musical) resulted in greater interference than silence conditions, with matched interference conditions producing the greatest interference. Overall, these results suggest that processing of linguistic and musical information draws on at least some of the same cognitive resources.
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Wu, Gang, Allan Belzberg, Jessica Nance, Sergio Gutierrez-Hernandez, Eva K. Ritzl, and Matthias Ringkamp. "Solutions to the technical challenges embedded in the current methods for intraoperative peripheral nerve action potential recordings." Journal of Neurosurgery 133, no. 3 (September 2020): 884–93. http://dx.doi.org/10.3171/2019.5.jns19146.
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OBJECTIVEIntraoperative nerve action potential (NAP) recording is a useful tool for surgeons to guide decisions on surgical approaches during nerve repair surgeries. However, current methods remain technically challenging. In particular, stimulus artifacts that contaminate or mask the NAP and therefore impair the interpretation of the recording are a common problem. The authors’ goal was to improve intraoperative NAP recording techniques by revisiting the methods in an experimental setting.METHODSFirst, NAPs were recorded from surgically exposed peripheral nerves in monkeys. For the authors to test their assumptions about observed artifacts, they then employed a simple model system. Finally, they applied their insights to clinical cases in the operating room.RESULTSIn monkey peripheral nerve recordings, large stimulus artifacts obscured NAPs every time the nerve segment (length 3–5 cm) was lifted up from the surrounding tissue, and NAPs could not be recorded. Artifacts were suppressed, and NAPs emerged when “bridge grounding” was applied, and this allowed the NAPs to be recorded easily and reliably. Tests in a model system suggested that exaggerated stimulus artifacts and unmasking of NAPs by bridge grounding are related to a loop effect that is created by lifting the nerve. Consequently, clean NAPs were acquired in “nonlifting” recordings from monkey peripheral nerves. In clinical cases, bridge grounding efficiently unmasked intraoperative NAP recordings, validating the authors’ principal concept in the clinical setting and allowing effective neurophysiological testing in the operating room.CONCLUSIONSTechnical challenges of intraoperative NAP recording are embedded in the current methods that recommend lifting the nerve from the tissue bed, thereby exaggerating stimulus artifacts by a loop effect. Better results can be achieved by performing nonlifting nerve recording or by applying bridge grounding. The authors not only tested their findings in an animal model but also applied them successfully in clinical practice.
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Kim, Bruce C., Sukeshwar Kannan, Sai Shravan Evana, and Seok-Ho Noh. "System-on-Chip Integrated MEMS Packages for RF LNA Testing and Self-Calibration." Journal of Microelectronics and Electronic Packaging 8, no. 4 (October 1, 2011): 154–63. http://dx.doi.org/10.4071/imaps.302.
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In this paper, we present MEMS-enhanced integrated package design which provides the capability to self-test and self-calibrate integrated circuit chips. We have developed a novel test technique where the test stimulus is generated by modulating the RF carrier signal with another signal mixed with additive white Gaussian noise. This novel test stimulus is provided as the input to the RF circuit and the peak-to-average ratio (PAR) is measured at the output. Simulations were carried out for fault-free and fault-induced circuit conditions, and their corresponding PARs were stored in the look-up table (LUT). Test simulations were performed and the results were compared with the look-up table to verify whether the device is fault-free. In faulty circuit conditions, calibration was performed using a tuning circuit made of MEMS switches. The entire validation of the design using the test technique and self-calibration of the RF circuit was automated using the calibration algorithm. This testing and self-calibration technique is exhaustive and efficient for present-day communication systems.
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Zhou, Xin, Dantong Zhu, Samson G. King, Cynthia J. Lees, Allyson J. Bennett, Emilio Salinas, Terrence R. Stanford, and Christos Constantinidis. "Behavioral response inhibition and maturation of goal representation in prefrontal cortex after puberty." Proceedings of the National Academy of Sciences 113, no. 12 (March 7, 2016): 3353–58. http://dx.doi.org/10.1073/pnas.1518147113.
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Executive functions including behavioral response inhibition mature after puberty, in tandem with structural changes in the prefrontal cortex. Little is known about how activity of prefrontal neurons relates to this profound cognitive development. To examine this, we tracked neuronal responses of the prefrontal cortex in monkeys as they transitioned from puberty into adulthood and compared activity at different developmental stages. Performance of the antisaccade task greatly improved in this period. Among neural mechanisms that could facilitate it, reduction of stimulus-driven activity, increased saccadic activity, or enhanced representation of the opposing goal location, only the latter was evident in adulthood. Greatly accentuated in adults, this neural correlate of vector inversion may be a prerequisite to the formation of a motor plan to look away from the stimulus. Our results suggest that the prefrontal mechanisms that underlie mature performance on the antisaccade task are more strongly associated with forming an alternative plan of action than with suppressing the neural impact of the prepotent stimulus.
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FONSLET, JESPER, KRISTIAN RUD-PETERSEN, SANDEEP KRISHNA, and MOGENS H. JENSEN. "PULSES AND CHAOS: DYNAMICAL RESPONSE IN A SIMPLE GENETIC OSCILLATOR." International Journal of Modern Physics B 21, no. 23n24 (September 30, 2007): 4083–90. http://dx.doi.org/10.1142/s0217979207045256.
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We investigate the dynamical behaviour of the genetic feedback loop present in the signalling network of the transcription factor NF -κ B . This transcription factor is one of the most important regulators in mammalian cells, involved in a large number of cellular responses. We find that when the external stimulus is constant, the concentration of NF -κ B inside the cell nucleus is either stationary or shows spiky oscillations. If the external stimulus is time dependent, the response can be more intricate. Here, we consider the response to pulsed and periodic stimuli. In the latter case the response can be chaotic with the NF -κ B concentration converging to a strange attractor. The corresponding bifurcation diagram is also presented.
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Haruno, Masahiko, and Mitsuo Kawato. "Different Neural Correlates of Reward Expectation and Reward Expectation Error in the Putamen and Caudate Nucleus During Stimulus-Action-Reward Association Learning." Journal of Neurophysiology 95, no. 2 (February 2006): 948–59. http://dx.doi.org/10.1152/jn.00382.2005.
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To select appropriate behaviors leading to rewards, the brain needs to learn associations among sensory stimuli, selected behaviors, and rewards. Recent imaging and neural-recording studies have revealed that the dorsal striatum plays an important role in learning such stimulus-action-reward associations. However, the putamen and caudate nucleus are embedded in distinct cortico-striatal loop circuits, predominantly connected to motor-related cerebral cortical areas and frontal association areas, respectively. This difference in their cortical connections suggests that the putamen and caudate nucleus are engaged in different functional aspects of stimulus-action-reward association learning. To determine whether this is the case, we conducted an event-related and computational model–based functional MRI (fMRI) study with a stochastic decision-making task in which a stimulus-action-reward association must be learned. A simple reinforcement learning model not only reproduced the subject's action selections reasonably well but also allowed us to quantitatively estimate each subject's temporal profiles of stimulus-action-reward association and reward-prediction error during learning trials. These two internal representations were used in the fMRI correlation analysis. The results revealed that neural correlates of the stimulus-action-reward association reside in the putamen, whereas a correlation with reward-prediction error was found largely in the caudate nucleus and ventral striatum. These nonuniform spatiotemporal distributions of neural correlates within the dorsal striatum were maintained consistently at various levels of task difficulty, suggesting a functional difference in the dorsal striatum between the putamen and caudate nucleus during stimulus-action-reward association learning.
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CHUMERIN, NIKOLAY, AGOSTINO GIBALDI, SILVIO P. SABATINI, and MARC M. VAN HULLE. "LEARNING EYE VERGENCE CONTROL FROM A DISTRIBUTED DISPARITY REPRESENTATION." International Journal of Neural Systems 20, no. 04 (August 2010): 267–78. http://dx.doi.org/10.1142/s0129065710002425.
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We present two neural models for vergence angle control of a robotic head, a simplified and a more complex one. Both models work in a closed-loop manner and do not rely on explicitly computed disparity, but extract the desired vergence angle from the post-processed response of a population of disparity tuned complex cells, the actual gaze direction and the actual vergence angle. The first model assumes that the gaze direction of the robotic head is orthogonal to its baseline and the stimulus is a frontoparallel plane orthogonal to the gaze direction. The second model goes beyond these assumptions, and operates reliably in the general case where all restrictions on the orientation of the gaze, as well as the stimulus position, type and orientation, are dropped.
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Brown, M. R. G., J. F. X. DeSouza, H. C. Goltz, K. Ford, R. S. Menon, M. A. Goodale, and S. Everling. "Comparison of Memory- and Visually Guided Saccades Using Event-Related fMRI." Journal of Neurophysiology 91, no. 2 (February 2004): 873–89. http://dx.doi.org/10.1152/jn.00382.2003.
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Previous functional imaging studies have shown an increased hemodynamic signal in several cortical areas when subjects perform memory-guided saccades than that when they perform visually guided saccades using blocked trial designs. It is unknown, however, whether this difference results from sensory processes associated with stimulus presentation, from processes occurring during the delay period before saccade generation, or from an increased motor signal for memory-guided saccades. We conducted fMRI using an event-related paradigm that separated stimulus-related, delay-related, and saccade-related activity. Subjects initially fixated a central cross, whose color indicated whether the trial was a memory- or a visually guided trial. A peripheral stimulus was then flashed at one of 4 possible locations. On memory-guided trials, subjects had to remember this location for the subsequent saccade, whereas the stimulus was a distractor on visually guided trials. Fixation cross disappearance after a delay period was the signal either to generate a memory-guided saccade or to look at a visual stimulus that was flashed on visually guided trials. We found slightly greater stimulus-related activation for visually guided trials in 3 right prefrontal regions and right rostral intraparietal sulcus (IPS). Memory-guided trials evoked greater delay-related activity in right posterior inferior frontal gyrus, right medial frontal eye field, bilateral supplementary eye field, right rostral IPS, and right ventral IPS but not in middle frontal gyrus. Right precentral gyrus and right rostral IPS exhibited greater saccade-related activation on memory-guided trials. We conclude that activation differences revealed by previous blocked experiments have different sources in different areas and that cortical saccade regions exhibit delay-related activation differences.
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Liu, Mochi, Sandeep Kumar, Anuj K. Sharma, and Andrew M. Leifer. "A high-throughput method to deliver targeted optogenetic stimulation to moving C. elegans populations." PLOS Biology 20, no. 1 (January 28, 2022): e3001524. http://dx.doi.org/10.1371/journal.pbio.3001524.
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We present a high-throughput optogenetic illumination system capable of simultaneous closed-loop light delivery to specified targets in populations of moving Caenorhabditis elegans. The instrument addresses three technical challenges: It delivers targeted illumination to specified regions of the animal’s body such as its head or tail; it automatically delivers stimuli triggered upon the animal’s behavior; and it achieves high throughput by targeting many animals simultaneously. The instrument was used to optogenetically probe the animal’s behavioral response to competing mechanosensory stimuli in the the anterior and posterior gentle touch receptor neurons. Responses to more than 43,418 stimulus events from a range of anterior–posterior intensity combinations were measured. The animal’s probability of sprinting forward in response to a mechanosensory stimulus depended on both the anterior and posterior stimulation intensity, while the probability of reversing depended primarily on the anterior stimulation intensity. We also probed the animal’s response to mechanosensory stimulation during the onset of turning, a relatively rare behavioral event, by delivering stimuli automatically when the animal began to turn. Using this closed-loop approach, over 9,700 stimulus events were delivered during turning onset at a rate of 9.2 events per worm hour, a greater than 25-fold increase in throughput compared to previous investigations. These measurements validate with greater statistical power previous findings that turning acts to gate mechanosensory evoked reversals. Compared to previous approaches, the current system offers targeted optogenetic stimulation to specific body regions or behaviors with many fold increases in throughput to better constrain quantitative models of sensorimotor processing.
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Collins, Stephen M. "IV. Modulation of intestinal inflammation by stress: basic mechanisms and clinical relevance." American Journal of Physiology-Gastrointestinal and Liver Physiology 280, no. 3 (March 1, 2001): G315—G318. http://dx.doi.org/10.1152/ajpgi.2001.280.3.g315.
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The stress response in a healthy organism is generally viewed as a warning and thus a protective reaction to a threat. However, the response may be deleterious if it is linked to an inflammatory stimulus or if it proceeds an inflammatory event. Prior stress enhances the response to an inflammatory stimulus by a mechanism that is independent of the release of hypothalamic corticotropin-releasing factor (CRF) or arginine vasopressin. Putative mechanisms include an increase in intestinal permeability as well as the release of the proinflammatory neuropeptide substance P. Stress may also reactivate previous inflammation when applied in conjunction with a small luminal stimulus. This reactivation involves increased permeability and requires the presence of T lymphocytes. Inflammatory mediators activate hypothalamic pathways, and a negative feedback loop, mediated by CRF release, has been proposed because animals with impaired hypothalamic CRF responses are more susceptible to inflammatory stimuli. Together, these experimental observations provide insights into the expression of inflammatory disorders in humans, including inflammatory bowel disease and postinfective irritable bowel syndrome.
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Dempsey, P. "News - Comment. View from Washington: Manufacturing - Covid-19 stimulus packages must look to the future." Engineering & Technology 15, no. 4 (May 1, 2020): 10. http://dx.doi.org/10.1049/et.2020.0419.
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Horr, Ninja K., and Massimiliano Di Luca. "Taking a long look at isochrony: Perceived duration increases with temporal, but not stimulus regularity." Attention, Perception, & Psychophysics 77, no. 2 (October 24, 2014): 592–602. http://dx.doi.org/10.3758/s13414-014-0787-z.
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Bölinger, Daniel, and Tim Gollisch. "Closed-Loop Measurements of Iso-Response Stimuli Reveal Dynamic Nonlinear Stimulus Integration in the Retina." Neuron 73, no. 2 (January 2012): 333–46. http://dx.doi.org/10.1016/j.neuron.2011.10.039.
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Yoshimura, Naoto, Koichi Morimoto, Mariko Murai, Yusaku Kihara, Fernando Marmolejo-Ramos, Veit Kubik, and Yuki Yamada. "Age of smile: a cross-cultural replication report of Ganel and Goodale (2018)." Journal of Cultural Cognitive Science 5, no. 1 (January 10, 2021): 1–15. http://dx.doi.org/10.1007/s41809-020-00072-3.
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AbstractSmiling is believed to make people look younger. Ganel and Goodale (Psychon Bull Rev 25(6):612–616, 10.3758/s13423-017-1306-8, 2018) proposed that this belief is a misconception rooted in popular media, based on their findings that people actually perceive smiling faces as older. However, they did not clarify whether this misconception can be generalized across cultures. We tested the cross-cultural validity of Ganel and Goodale’s findings by collecting data from Japanese and Swedish participants. Specifically, we aimed to replicate Ganel and Goodale’s study using segregated sets of Japanese and Swedish facial stimuli, and including Japanese and Swedish participants in groups asked to estimate the age of either Japanese or Swedish faces (two groups of participants × two groups of stimuli; four groups total). Our multiverse analytical approach consistently showed that the participants evaluated smiling faces as older in direct evaluations, regardless of the facial stimuli culture or their nationality, although they believed that smiling makes people look younger. Further, we hypothesized that the effect of wrinkles around the eyes on the estimation of age would vary with the stimulus culture, based on previous studies. However, we found no differences in age estimates by stimulus culture in the present study. Our results showed that we successfully replicated Ganel and Goodale (2018) in a cross-cultural context. Our study thus clarified that the belief that smiling makes people look younger is a common cultural misconception.
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Tsur, Omer, Yana Khrapunsky, and Rony Azouz. "Sensorimotor integration in the whisker somatosensory brain stem trigeminal loop." Journal of Neurophysiology 122, no. 5 (November 1, 2019): 2061–75. http://dx.doi.org/10.1152/jn.00116.2019.
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The rodent’s vibrissal system is a useful model system for studying sensorimotor integration in perception. This integration determines the way in which sensory information is acquired by sensory organs and the motor commands that control them. The initial instance of sensorimotor integration in the whisker somatosensory system is implemented in the brain stem loop and may be essential to the way rodents explore and sense their environment. To examine the nature of these sensorimotor interactions, we recorded from lightly anesthetized rats in vivo and brain stem slices in vitro and isolated specific parts of this loop. We found that motor feedback to the vibrissal pad serves as a dynamic gain controller that controls the response of first-order sensory neurons by increasing and decreasing sensitivity to lower and higher tactile stimulus magnitudes, respectively. This delicate mechanism is mediated through tactile stimulus magnitude-dependent motor feedback. Conversely, tactile inputs affect the motor whisking output through influences on the rhythmic whisking circuitry, thus changing whisking kinetics. Similarly, tactile influences also modify the whisking amplitude through synaptic and intrinsic neuronal interaction in the facial nucleus, resulting in facilitation or suppression of whisking amplitude. These results point to the vast range of mechanisms underlying sensorimotor integration in the brain stem loop. NEW & NOTEWORTHY Sensorimotor integration is a process in which sensory and motor information is combined to control the flow of sensory information, as well as to adjust the motor system output. We found in the rodent’s whisker somatosensory system mutual influences between tactile inputs and motor output, in which motor neurons control the flow of sensory information depending on their magnitude. Conversely, sensory information can control the magnitude and kinetics of whisker movement.
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Cheung, Po-yan, Yi Zhang, Jiafu Long, Shengcai Lin, Mingjie Zhang, Yong Jiang, and Zhenguo Wu. "p150Glued, Dynein, and Microtubules Are Specifically Required for Activation of MKK3/6 and p38 MAPKs." Journal of Biological Chemistry 279, no. 44 (September 16, 2004): 45308–11. http://dx.doi.org/10.1074/jbc.c400333200.
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To look for regulators of the mitogen-activated protein kinase (MAPK) kinase 6 (MKK6), a yeast two-hybrid screen was initiated using MKK6 as bait. p150Glueddynactin, a key component of the cytoplasmic dynein-dynactin motor complex, was found to specifically interact with MKK6 and its close homologue MKK3. Silencing of p150Gluedexpression by small interference RNA reduced the stimulus-induced phosphorylation of MKK3/6 and p38 MAPKs. The similar adverse effect was also seen when the cytoplasmic dynein motor was disrupted by other means. Like p150Glued, MKK3/6 directly associate with microtubules. Disruption of microtubules prior to cell stimulation specifically inhibits the stimulus-induced phosphorylation of both MKK3/6 and p38 MAPKs. Our unexpected findings reveal a specific requirement for p150Glued/dynein/functional microtubules in activation of MKK3/6 and p38 MAPKsin vivo.
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Yang, J. F., J. Fung, M. Edamura, R. Blunt, R. B. Stein, and H. Barbeau. "H-Reflex Modulation During Walking in Spastic Paretic Subjects." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 18, no. 4 (November 1991): 443–52. http://dx.doi.org/10.1017/s0317167100032133.
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ABSTRACT:Hoffmann (H) reflexes were elicited from the soleus muscle during treadmill walking in 21 spastic paretic patients. The soleus and tibialis anterior muscles were reciprocally activated during walking in most patients, much like that observed in healthy individuals. The pattern of H-reflex modulation varied considerably between patients, from being relatively normal in some patients to a complete absence of modulation in others. The most common pattern observed was a lack of H-reflex modulation through the stance phase and slight depression of the reflex in the swing phase, considerably less modulation than that of normal subjects under comparable walking conditions. The high reflex amplitudes during periods of the step cycle such as early stance seems to be related to the stretch-induced large electromyogram bursts in the soleus in some subjects. The abnormally active reflexes appear to contribute to the clonus encountered during walking in these patients. In three patients who were able to walk for extended periods, the effect of stimulus intensity was examined. Two of these patients showed a greater degree of reflex modulation at lower stimulus intensities, suggesting that the lack of modulation observed at higher stimulus intensities is a result of saturation of the reflex loop. In six other patients, however, no reflex modulation could be demonstrated even at very low stimulus intensities.
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Geake, John. "Fractal Computer Graphics as a Stimulus for the Enhancement of Perceptual Sensitivity to the Natural Environment." Australian Journal of Environmental Education 8 (1992): 1–16. http://dx.doi.org/10.1017/s0814062600003268.
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The beauty and freshness of fractal geometry suggests that once again we are at the start of science and mathematics… women and men will look back on this era much as we look back to the early Greeks. (Barnsley, 1989, p. 5)Such enthusiasm for a perceived new paradigm in the mathematical sciences is beginning to emerge within broader educational contexts (Devaney & Keen, 1989; Egnatoff, 1989; Geake, 1990a & 1990b). Much of the interest in fractal geometry has focussed on its ability to describe complex natural phenomena (Mandelbrot, 1983 & 1990; Pickover, 1987; Barnsley, 1988). Recent investigations into the visual perception of natural imagery have used fractal mathematics in describing the characteristics of such perception (Pentland, 1984; Field, 1987; Peli, 1990). This study examined human visual perception of the fractal form found in the natural environment. Specifically, this research project examined how exposure to a program of fractal computer graphics affected the perceptual sensitivity of primary school children to the natural visual environment. The underpinning rationale was to address a long standing challenge of Linke (1980) to develop a stronger theoretical basis for environmental education in Australia.
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Holly, Jan E., and Gin McCollum. "Constructive perception of self-motion." Journal of Vestibular Research 18, no. 5-6 (April 1, 2009): 249–66. http://dx.doi.org/10.3233/ves-2008-185-602.
Full textAbstract:
This review focusses attention on a ragged edge of our knowledge of self-motion perception, where understanding ends but there are experimental results to indicate that present approaches to analysis are inadequate. Although self-motion perception displays processes of "top-down" construction, it is typically analyzed as if it is nothing more than a deformation of the stimulus, using a "bottom-up" and input/output approach beginning with the transduction of the stimulus. Analysis often focusses on the extent to which passive transduction of the movement stimulus is accurate. Some perceptual processes that deform or transform the stimulus arise from the way known properties of sensory receptors contribute to perceptual accuracy or inaccuracy. However, further constructive processes in self-motion perception that involve discrete transformations are not well understood. We introduce constructive perception with a linguistic example which displays familiar discrete properties, then look closely at self-motion perception. Examples of self-motion perception begin with cases in which constructive processes transform particular properties of the stimulus. These transformations allow the nervous system to compose whole percepts of movement; that is, self-motion perception acts at a whole-movement level of analysis, rather than passively transducing individual cues. These whole-movement percepts may be paradoxical. In addition, a single stimulus may give rise to multiple perceptions. After reviewing self-motion perception studies, we discuss research methods for delineating principles of the constructed perception of self-motion. The habit of viewing self-motion illusions only as continuous deformations of the stimulus may be blinding the field to other perceptual phenomena, including those best characterized using the mathematics of discrete transformations or mathematical relationships relating sensory modalities in novel, sometimes discrete ways. Analysis of experiments such as these is required to mathematically formalize elements of self-motion perception, the transformations they may undergo, consistency principles, and logical structure underlying multiplicity of perceptions. Such analysis will lead to perceptual rules analogous to those recognized in visual perception.