Dependence of the stimulus-driven microsaccade rate signature in rhesus macaque monkeys on visual stimulus size and polarity

2020 ◽  
Author(s):  
Tatiana Malevich ◽  
Antimo Buonocore ◽  
Ziad M. Hafed
Keyword(s):  
Stimulus Onset ◽  
Stimulus Size ◽  
Neural Mechanisms ◽  
Oculomotor Control ◽  
Background Luminance ◽  
Rapid Reduction ◽  
Sensory Stimuli ◽  
Macaque Monkeys ◽  
Early Access ◽  
Steady Rate

Microsaccades have a steady rate of occurrence during maintained gaze fixation, which gets transiently modulated by abrupt sensory stimuli. Such modulation, characterized by a rapid reduction in microsaccade frequency followed by a stronger rebound phase of high microsaccade rate, is often described as the microsaccadic rate signature, owing to its stereotyped nature. Here we investigated the impacts of stimulus polarity (luminance increments or luminance decrements relative to background luminance) and size on the microsaccadic rate signature. We presented brief, behaviorally-irrelevant visual flashes consisting of large or small white or black stimuli over an otherwise gray image background. Both large and small stimuli caused robust early microsaccadic inhibition, but post-inhibition microsaccade rate rebound was significantly delayed and weakened for large stimuli when compared to small ones. Critically, small black stimuli were associated with stronger modulations in the microsaccade rate signature than small white stimuli, particularly in the post-inhibition rebound phase, and black stimuli also amplified the incidence of early stimulus-directed microsaccades. Our results demonstrate that the microsaccadic rate signature is sensitive to stimulus size and polarity, and they point to dissociable neural mechanisms underlying early microsaccadic inhibition after stimulus onset and later microsaccadic rate rebound at longer times thereafter. These results also demonstrate early access of oculomotor control circuitry to diverse sensory representations, particularly for momentarily inhibiting saccade generation with short latencies.

scholarly journals Dependence of the stimulus-driven microsaccade rate signature on visual stimulus polarity

2020 ◽  
Author(s):  
Tatiana Malevich ◽  
Antimo Buonocore ◽  
Ziad M. Hafed
Keyword(s):  
Stimulus Onset ◽  
Neural Mechanisms ◽  
Oculomotor Control ◽  
Background Luminance ◽  
Subsequent Increase ◽  
Rapid Reduction ◽  
Sensory Stimuli ◽  
Gaze Fixation ◽  
Early Access ◽  
Steady Rate

AbstractMicrosaccades have a steady rate of occurrence during maintained gaze fixation, which gets transiently modulated by abrupt sensory stimuli. Such modulation, characterized by a rapid reduction in microsaccade frequency followed by a stronger rebound phase of high microsaccade rate, is often described as the microsaccadic rate signature, owing to its stereotyped nature. Here we investigated the impacts of stimulus polarity (luminance increments or luminance decrements relative to background luminance) and size on the microsaccadic rate signature. We presented brief visual flashes consisting of large or small white or black stimuli over an otherwise gray image background. Both large and small stimuli caused robust early microsaccadic inhibition, but only small ones caused a subsequent increase in microsaccade frequency above baseline microsaccade rate. Critically, small black stimuli were always associated with stronger modulations in microsaccade rate after stimulus onset than small white stimuli, particularly in the post-inhibition rebound phase of the microsaccadic rate signature. Because small stimuli were also associated with expected direction oscillations to and away from their locations of appearance, these stronger rate modulations in the rebound phase meant higher likelihoods of microsaccades opposite the black flash locations relative to the white flash locations. Our results demonstrate that the microsaccadic rate signature is sensitive to stimulus polarity, and they point to dissociable neural mechanisms underlying early microsaccadic inhibition after stimulus onset and later microsaccadic rate rebound at longer times thereafter. These results also demonstrate early access of oculomotor control circuitry to sensory representations, particularly for momentarily inhibiting saccade generation.New and noteworthyMicrosaccades are small saccades that occur during gaze fixation. Microsaccade rate is transiently reduced after sudden stimulus onsets, and then strongly rebounds before returning to baseline. We explored the influence of stimulus polarity (black versus white) on this “rate signature”. We found that small black stimuli cause stronger microsaccadic modulations than white ones, but primarily in the rebound phase. This suggests dissociated neural mechanisms for microsaccadic inhibition and subsequent rebound in the microsaccadic rate signature.

scholarly journals Neural mechanisms underlying regulation of empathy and altruism by beliefs of others' pain

2021 ◽  
Author(s):  
Tao Yu ◽  
Shihui Han
Keyword(s):  
Real Life ◽  
Stimulus Onset ◽  
Neural Mechanisms ◽  
Altruistic Behavior ◽  
Emotional States ◽  
Neural Responses ◽  
Temporoparietal Junction ◽  
Subjective Estimation ◽  
Show Evidence

Perceived cues signaling others' pain induce empathy that in turn motivates altruistic behavior toward those who appear suffering. This perception-emotion-behavior reactivity is the core of human altruism but does not always occur in real life situations. Here, by integrating behavioral and multimodal neuroimaging measures, we investigate neural mechanisms underlying the functional role of beliefs of others' pain in modulating empathy and altruism. We show evidence that decreasing (or enhancing) beliefs of others' pain reduces (or increases) subjective estimation of others' painful emotional states and monetary donations to those who show pain expressions. Moreover, decreasing beliefs of others' pain attenuates neural responses to perceived cues signaling others' pain within 200 ms after stimulus onset and modulate neural responses to others' pain in the frontal cortices and temporoparietal junction. Our findings highlight beliefs of others' pain as a fundamental cognitive basis of human empathy and altruism and unravel the intermediate neural architecture.

scholarly journals Cortical activity is more stable when sensory stimuli are consciously perceived

2015 ◽  
Vol 112 (16) ◽  
pp. E2083-E2092 ◽  
Author(s):  
Aaron Schurger ◽  
Ioannis Sarigiannidis ◽  
Lionel Naccache ◽  
Jacobo D. Sitt ◽  
Stanislas Dehaene
Keyword(s):  
Spatial Scales ◽  
Threshold Level ◽  
Stimulus Onset ◽  
Conscious Perception ◽  
Subjective Report ◽  
Sensory Stimuli ◽  
Eeg Data ◽  
Pattern Similarity ◽  
The Stability ◽  
Global Brain

According to recent evidence, stimulus-tuned neurons in the cerebral cortex exhibit reduced variability in firing rate across trials, after the onset of a stimulus. However, in order for a reduction in variability to be directly relevant to perception and behavior, it must be realized within trial—the pattern of activity must be relatively stable. Stability is characteristic of decision states in recurrent attractor networks, and its possible relevance to conscious perception has been suggested by theorists. However, it is difficult to measure on the within-trial time scales and broadly distributed spatial scales relevant to perception. We recorded simultaneous magneto- and electroencephalography (MEG and EEG) data while subjects observed threshold-level visual stimuli. Pattern-similarity analyses applied to the data from MEG gradiometers uncovered a pronounced decrease in variability across trials after stimulus onset, consistent with previous single-unit data. This was followed by a significant divergence in variability depending upon subjective report (seen/unseen), with seen trials exhibiting less variability. Applying the same analysis across time, within trial, we found that the latter effect coincided in time with a difference in the stability of the pattern of activity. Stability alone could be used to classify data from individual trials as “seen” or “unseen.” The same metric applied to EEG data from patients with disorders of consciousness exposed to auditory stimuli diverged parametrically according to clinically diagnosed level of consciousness. Differences in signal strength could not account for these results. Conscious perception may involve the transient stabilization of distributed cortical networks, corresponding to a global brain-scale decision.

scholarly journals A neural basis for the spatial suppression of visual motion perception

2016 ◽  
Author(s):  
Liu D. Liu ◽  
Ralf M. Haefner ◽  
Christopher C. Pack
Keyword(s):  
Cortical Area ◽  
Visual Motion ◽  
Receptive Fields ◽  
Stimulus Size ◽  
Neural Mechanisms ◽  
Stimulus Information ◽  
Neural Basis ◽  
Visual Motion Perception ◽  
Neuronal Populations ◽  
Perceptual Performance

AbstractIn theory, sensory perception should be more accurate when more neurons contribute to the representation of a stimulus. However, psychophysical experiments that use larger stimuli to activate larger pools of neurons sometimes report impoverished perceptual performance. To determine the neural mechanisms underlying these paradoxical findings, we trained monkeys to discriminate the direction of motion of visual stimuli that varied in size across trials, while simultaneously recording from populations of motion-sensitive neurons in cortical area MT. We used the resulting data to constrain a computational model that explained the behavioral data as an interaction of three main mechanisms: noise correlations, which prevented stimulus information from growing with stimulus size; neural surround suppression, which decreased sensitivity for large stimuli; and a read-out strategy that emphasized neurons with receptive fields near the stimulus center. These results suggest that paradoxical percepts reflect tradeoffs between sensitivity and noise in neuronal populations.

Neural Mechanisms of Audiovisual Integration in Integrated Processing for Verbal Perception and Spatial Factors

2013 ◽  
pp. 327-336
Author(s):  
Yulin Gao ◽  
Weiping Yang ◽  
Jingjing Yang ◽  
Takahashi Satoshi ◽  
Jinglong Wu
Keyword(s):  
Behavioral Responses ◽  
Spatial Location ◽  
Relevant Information ◽  
Superior Temporal Sulcus ◽  
Audiovisual Integration ◽  
Neural Mechanisms ◽  
Future Research ◽  
Sensory Stimuli ◽  
Integrated Processing ◽  
The Relationship

People perceive information from the outside world using several sensory organs rather than through a single one. First, relevant information is processed in the corresponding sensory area independently and then integrated in a multi-sensory processing cerebral region. The integration process influences the later behavioral responses to the sensory stimuli. Based on previous research, this chapter summarizes the neural mechanisms and the influencing factors of audiovisual integration. These include the relationship between the spatial location of auditory stimuli, visual stimuli, and verbal perception. According to research in neurology, the main neural mechanisms of audiovisual integration are from the superior temporal sulcus in the rear left region of the human brain. In the future, research on the combination of virtual reality technology and audiovisual integration should be continued to enable the research achievements to have more ecological effects.

Modular distribution of neurons with slowly adapting and rapidly adapting responses in area 3b of somatosensory cortex in monkeys

1984 ◽  
Vol 51 (4) ◽  
pp. 724-744 ◽  
Author(s):  
M. Sur ◽  
J. T. Wall ◽  
J. H. Kaas
Keyword(s):  
Somatosensory Cortex ◽  
Receptive Fields ◽  
Systematic Position ◽  
Stimulus Onset ◽  
Cortical Layers ◽  
Single Digit ◽  
Macaque Monkeys ◽  
Predominant Orientation ◽  
Skin Indentation ◽  
Area 3B

Recordings from the representations of the glabrous digits in area 3b of the somatosensory cortex of owl and macaque monkeys revealed two types of neurons. Rapidly adapting (RA) neurons responded only at the onset and offset of a 1-s skin indentation. Slowly adapting (SA) neurons also responded to stimulus onset and offset but, in addition, they responded throughout the 1-s skin indentation. RA neurons were found in all cortical layers while SA neurons were found only in the middle cortical layers. In electrode penetrations perpendicular to the layers, some penetrations encountered only RA neurons (RA penetrations), while other penetrations first encountered RA neurons, then SA neurons, and finally RA neurons again (SA penetrations). When closely spaced electrode penetrations were made throughout the representation of a single digit, it was apparent that RA and SA penetrations were not randomly distributed. The distribution suggested the existence of separate clusters or bands of SA and RA neurons in the middle layers of cortex. The predominant orientation of the SA and RA regions was rostrocaudally along the lengths of the digit representations. The SA and RA bands varied in width, had no systematic position in the representation of individual digits, and often crossed from the representation of one digit to another. Because of overlapping receptive fields for neurons in adjoining bands, the SA and RA bands appeared to represent the digits separately. This would allow all skin surfaces for each digit to be subserved by both types of neurons.

scholarly journals Causal neural mechanisms of context-based object recognition

2021 ◽  
Author(s):  
Miles Wischnewski ◽  
Marius V. Peelen
Keyword(s):  
Visual Cortex ◽  
Object Recognition ◽  
Parallel Processing ◽  
Occipital Cortex ◽  
Stimulus Onset ◽  
Neural Mechanisms ◽  
Object Representations ◽  
Early Visual Cortex ◽  
Scene Information ◽  
Lateral Occipital Cortex

Objects can be recognized based on their intrinsic features, including shape, color, and texture. In daily life, however, such features are often not clearly visible, for example when objects appear in the periphery, in clutter, or at a distance. Interestingly, object recognition can still be highly accurate under these conditions when objects are seen within their typical scene context. What are the neural mechanisms of context-based object recognition? According to parallel processing accounts, context-based object recognition is supported by the parallel processing of object and scene information in separate pathways. Output of these pathways is then combined in downstream regions, leading to contextual benefits in object recognition. Alternatively, according to feedback accounts, context-based object recognition is supported by feedback from scene-selective to object-selective regions. Here, in three pre-registered transcranial magnetic stimulation (TMS) experiments, we tested a key prediction of the feedback hypothesis: that scene-selective cortex causally and selectively supports context-based object recognition before object-selective cortex does. Early visual cortex (EVC), object-selective lateral occipital cortex (LOC), and scene-selective occipital place area (OPA) were stimulated at three time points relative to stimulus onset while participants categorized degraded objects in scenes and intact objects in isolation, in different trials. Results confirmed our predictions: relative to isolated object recognition, context-based object recognition was selectively and causally supported by OPA at 160-200 ms after onset, followed by LOC at 260-300 ms after onset. These results indicate that context-based expectations facilitate object recognition by disambiguating object representations in visual cortex.

scholarly journals The Relationship between Trial-by-Trial Variability and Oscillations of Cortical Population Activity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Edan Daniel ◽  
Thomas Meindertsma ◽  
Ayelet Arazi ◽  
Tobias H. Donner ◽  
Ilan Dinstein
Keyword(s):  
Stimulus Onset ◽  
Alternative Mechanism ◽  
Beta Band ◽  
Population Activity ◽  
Sensory Stimuli ◽  
Electrophysiological Recordings ◽  
Phase Alignment ◽  
Tightly Coupled ◽  
Alpha Beta ◽  
Neural Variability

AbstractNeural activity fluctuates over time, creating considerable variability across trials. This trial-by-trial neural variability is dramatically reduced (“quenched”) after the presentation of sensory stimuli. Likewise, the power of neural oscillations, primarily in the alpha-beta band, is also reduced after stimulus onset. Despite their similarity, these phenomena have so far been studied and discussed independently. We hypothesized that the two phenomena are tightly coupled in electrophysiological recordings of large cortical neural populations. To test this, we examined magnetoencephalography (MEG) recordings of healthy subjects viewing repeated presentations of a visual stimulus. The timing, amplitude, and spatial topography of variability-quenching and power-suppression were remarkably similar. Neural variability quenching was eliminated by excluding the alpha-beta band from the recordings, but not by excluding other frequency-bands. Moreover, individual magnitudes of alpha-beta band-power explained 86% of between-subject differences in variability quenching. An alternative mechanism that may generate variability quenching is increased phase alignment across trials. However, changes in inter-trial-phase-coherence (ITPC) exhibited distinct timing and no correlations with the magnitude of variability quenching in individual participants. These results reveal that neural variability quenching is tightly coupled with stimulus-induced changes in the power of alpha-beta band oscillations, associating two phenomena that have so far been studied in isolation.

scholarly journals Timing in Predictive Coding: The Roles of Task Relevance and Global Probability

2017 ◽  
Vol 29 (5) ◽  
pp. 780-792 ◽  
Author(s):  
Chase Sherwell ◽  
Marta I. Garrido ◽  
Ross Cunnington
Keyword(s):  
A Priori ◽  
Predictive Coding ◽  
Stimulus Onset ◽  
Interactive Effects ◽  
Sensory Stimuli ◽  
Task Relevance ◽  
Temporal Prediction ◽  
Preparatory Activity ◽  
Sensory Responses ◽  
Sensory Neural

Predictive coding models of attention propose that attention and prediction operate synergistically to optimize perception, as reflected in interactive effects on early sensory neural responses. It is yet unclear whether attention and prediction based on the temporal attributes of expected events operate in a similar fashion. We investigated how attention and prediction based on timing interact by manipulating the task relevance and a priori probability of auditory stimulus onset timing within a go/no-go task while recording EEG. Preparatory activity, as indexed via the contingent negative variation, reflected temporally specific anticipation as a function of both attention and prediction. Higher stimulus probability led to significant predictive N1 suppression; however, we failed to find an effect of task relevance on N1 amplitude and an interaction of task relevance with prediction. We suggest the predictability of sensory timing is the predominant influence on early sensory responses where a priori probabilities allow for strong prior beliefs. When this is the case, we find that the effects of temporal prediction on early sensory responses are independent of the task relevance of sensory stimuli. Our findings contribute to the expansion of predictive coding frameworks to include the role of timing in sensory processing.

Sign in / Sign up

Export Citation Format

Share Document