scholarly journals Early neural activity changes associated with visual conscious perception

2021 ◽  
Author(s):  
Aya Khalaf ◽  
Sharif Kronemer ◽  
Kate Christison-Lagay ◽  
Hunki Kwon ◽  
Jiajia Li ◽  
...  
Keyword(s):  
Neural Activity ◽  
Temporal Cortex ◽  
Occipital Cortex ◽  
Stimulus Onset ◽  
Conscious Perception ◽  
Continuous Performance Task ◽  
Perceptual Decision Making ◽  
Gamma Power ◽  
In Series ◽  
The Right

The neural mechanisms of visual conscious perception have been investigated for decades. However, the spatiotemporal dynamics associated with the earliest neural responses following consciously perceived stimuli are still poorly understood. Using a dataset of intracranial EEG recordings, the current study aims to investigate the neural activity changes associated with the earliest stages of visual conscious perception. Subjects (N=10, 1,693 grey matter electrode contacts) completed a continuous performance task in which individual letters were presented in series and subjects were asked to press a button when they saw a target letter. Broadband gamma power (40-115Hz) dynamics were analyzed in comparison to baseline prior to stimulus and contrasted for target trials with button presses and non-target trials without button presses. Regardless of event type, we observed early gamma power changes within 30-150 ms from stimulus onset in a network including increases in bilateral occipital, fusiform, frontal (including frontal eye fields), and medial temporal cortex, increases in left lateral parietal-temporal cortex, and decreases in the right anterior medial occipital cortex. No significant differences were observed between target and non-target stimuli until >150 ms post-stimulus, when we saw greater gamma power increases in left motor and premotor areas, suggesting a possible role of these later signals in perceptual decision making and/or motor responses with the right hand. The early gamma power findings suggest a broadly distributed cortical visual detection network that is engaged at early times tens of milliseconds after signal transduction from the retina.

scholarly journals The Rapid Extraction of Gist—Early Neural Correlates of High-level Visual Processing

2012 ◽  
Vol 24 (2) ◽  
pp. 521-529 ◽  
Author(s):  
Frank Oppermann ◽  
Uwe Hassler ◽  
Jörg D. Jescheniak ◽  
Thomas Gruber
Keyword(s):  
Visual Processing ◽  
Time Course ◽  
Occipital Cortex ◽  
Stimulus Onset ◽  
Gamma Band ◽  
Oscillatory Activity ◽  
Rapid Extraction ◽  
The Right ◽  
High Level ◽  
Individual Objects

The human cognitive system is highly efficient in extracting information from our visual environment. This efficiency is based on acquired knowledge that guides our attention toward relevant events and promotes the recognition of individual objects as they appear in visual scenes. The experience-based representation of such knowledge contains not only information about the individual objects but also about relations between them, such as the typical context in which individual objects co-occur. The present EEG study aimed at exploring the availability of such relational knowledge in the time course of visual scene processing, using oscillatory evoked gamma-band responses as a neural correlate for a currently activated cortical stimulus representation. Participants decided whether two simultaneously presented objects were conceptually coherent (e.g., mouse–cheese) or not (e.g., crown–mushroom). We obtained increased evoked gamma-band responses for coherent scenes compared with incoherent scenes beginning as early as 70 msec after stimulus onset within a distributed cortical network, including the right temporal, the right frontal, and the bilateral occipital cortex. This finding provides empirical evidence for the functional importance of evoked oscillatory activity in high-level vision beyond the visual cortex and, thus, gives new insights into the functional relevance of neuronal interactions. It also indicates the very early availability of experience-based knowledge that might be regarded as a fundamental mechanism for the rapid extraction of the gist of a scene.

scholarly journals Transient neuronal suppression for exploitation of new sensory evidence

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Maxwell Shinn ◽  
Daeyeol Lee ◽  
John D. Murray ◽  
Hyojung Seo
Keyword(s):  
Decision Making ◽  
Neural Activity ◽  
Temporal Integration ◽  
Motor Preparation ◽  
Stimulus Onset ◽  
Frontal Eye Field ◽  
Perceptual Decision Making ◽  
Behavioral Studies ◽  
The Face ◽  
Sensory Evidence

AbstractIn noisy but stationary environments, decisions should be based on the temporal integration of sequentially sampled evidence. This strategy has been supported by many behavioral studies and is qualitatively consistent with neural activity in multiple brain areas. By contrast, decision-making in the face of non-stationary sensory evidence remains poorly understood. Here, we trained monkeys to identify and respond via saccade to the dominant color of a dynamically refreshed bicolor patch that becomes informative after a variable delay. Animals’ behavioral responses were briefly suppressed after evidence changes, and many neurons in the frontal eye field displayed a corresponding dip in activity at this time, similar to that frequently observed after stimulus onset but sensitive to stimulus strength. Generalized drift-diffusion models revealed consistency of behavior and neural activity with brief suppression of motor output, but not with pausing or resetting of evidence accumulation. These results suggest that momentary arrest of motor preparation is important for dynamic perceptual decision making.

scholarly journals Spatio-temporally specific transcranial magnetic stimulation to test the locus of perceptual decision making in the human brain

2018 ◽  
Author(s):  
Bruce Luber ◽  
David C. Jangraw ◽  
Greg Appelbaum ◽  
Austin Harrison ◽  
Susan Hilbig ◽  
...  
Keyword(s):  
Decision Making ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Performance Enhancement ◽  
Occipital Cortex ◽  
Stimulus Onset ◽  
Perceptual Decision Making ◽  
Perceptual Decision ◽  
Slow Reaction Time ◽  
Predictive Validation

AbstractPrevious research modeling EEG, fMRI and behavioral data has identified three spatially distributed brain networks that activate in temporal sequence, and are thought to enable perceptual decision-making during face-versus-car categorization. These studies have linked late activation (>300ms post stimulus onset) in the lateral occipital cortex (LOC) to object discrimination processes. We applied paired-pulse transcranial magnetic stimulation (ppTMS) to LOC at different temporal latencies with the specific prediction, based on these studies, that ppTMS beginning at 400ms after stimulus onset would slow reaction time (RT) performance. Thirteen healthy adults performed a two-alternative forced choice task selecting whether a car or face was present on each trial amidst visual noise pre-titrated to approximate 79% accuracy. ppTMS, with pulses separated by 50ms, was applied at one of five stimulus onset asynchronies: -200, 200, 400, 450, or 500ms, and a sixth no-stimulation condition. As predicted, TMS at 400ms resulted in significant slowing of RTs, providing causal evidence in support of LOC contribution to perceptual decision processing. In addition, TMS delivered at -200ms resulted in faster RTs, indicating early stimulation may result in performance enhancement. These findings build upon correlational EEG and fMRI observations and demonstrate the use of TMS in predictive validation of psychophysiological models.

scholarly journals Functional preference for object sounds but not for voices in the occipito-temporal cortex of early blind individuals

2017 ◽  
Author(s):  
Giulia Dormal ◽  
Maxime Pelland ◽  
Mohamed Rezk ◽  
Esther Yakobov ◽  
Franco Lepore ◽  
...  
Keyword(s):  
Temporal Cortex ◽  
Primary Auditory Cortex ◽  
Familiar Object ◽  
Occipital Cortex ◽  
Functional Coupling ◽  
Level Control ◽  
Crossmodal Plasticity ◽  
Categorical Responses ◽  
The Right ◽  
Blind Individuals

AbstractSounds activate occipital regions in early blind individuals. How different sound categories map onto specific regions of the occipital cortex remains however debated. We used fMRI to characterize brain responses of early blind and sighted individuals to familiar object sounds, human voices and their respective low-level control sounds. Sighted participants were additionally tested when viewing pictures of faces, objects and phase-scrambled control pictures. In both early blind and sighted, a double dissociation was evidenced in bilateral auditory cortices between responses to voices and object sounds: voices elicited categorical responses in bilateral superior temporal sulci while object sounds elicited categorical responses along the lateral fissure bilaterally, including the primary auditory cortex and planum temporale. Outside of the auditory regions, object sounds additionally elicited categorical responses in left lateral and ventral occipito-temporal regions in both groups. These regions also showed response preference for images of objects in the sighted, thus suggesting a functional specialization in these regions that is independent of sensory input and visual experience. Between-group comparisons revealed that only in the blind group, categorical responses to object sounds extended more posteriorly into the occipital cortex. Functional connectivity analyses evidenced a selective increase in the functional coupling between these reorganized regions and regions of the ventral occipito-temporal cortex in the early blind. In contrast, vocal sounds did not elicit preferential responses in the occipital cortex in either group. Nevertheless, enhanced voice-selective connectivity between the left temporal voice area and the right fusiform gyrus were found in the blind. Altogether, these findings suggest that separate auditory categories are not equipotent in driving selective auditory recruitment of occipito-temporal regions in the absence of developmental vision, highlighting domain-region constraints on the expression of crossmodal plasticity.

Time-course of Posterior Parietal and Occipital Cortex Contribution to Sound Localization

2008 ◽  
Vol 20 (8) ◽  
pp. 1454-1463 ◽  
Author(s):  
Olivier Collignon ◽  
Marco Davare ◽  
Anne G. De Volder ◽  
Colline Poirier ◽  
Etienne Olivier ◽  
...  
Keyword(s):  
Time Course ◽  
Posterior Parietal Cortex ◽  
Space Perception ◽  
Occipital Cortex ◽  
Stimulus Onset ◽  
Spatial Processing ◽  
Auditory Space ◽  
Posterior Parietal ◽  
The Right ◽  
Precise Time

It has been suggested that both the posterior parietal cortex (PPC) and the extrastriate occipital cortex (OC) participate in the spatial processing of sounds. However, the precise time-course of their contribution remains unknown, which is of particular interest, considering that it could give new insights into the mechanisms underlying auditory space perception. To address this issue, we have used event-related transcranial magnetic stimulation (TMS) to induce virtual lesions of either the right PPC or right OC at different delays in subjects performing a sound lateralization task. Our results confirmed that these two areas participate in the spatial processing of sounds. More precisely, we found that TMS applied over the right OC 50 msec after the stimulus onset significantly impaired the localization of sounds presented either to the right or to the left side. Moreover, right PPC virtual lesions induced 100 and 150 msec after sound presentation led to a rightward bias for stimuli delivered on the center and on the left side, reproducing transiently the deficits commonly observed in hemineglect patients. The finding that the right OC is involved in sound processing before the right PPC suggests that the OC exerts a feedforward influence on the PPC during auditory spatial processing.

scholarly journals Prior expectations of motion direction modulate early sensory processing

2020 ◽  
Author(s):  
Fraser Aitken ◽  
Georgia Turner ◽  
Peter Kok
Keyword(s):  
Visual Stimulus ◽  
Sensory Processing ◽  
Neural Activity ◽  
Stimulus Onset ◽  
Perceptual Bias ◽  
Perceptual Process ◽  
Perceptual Decision Making ◽  
Auditory Cues ◽  
Sensory Inputs ◽  
Human Participants

AbstractPerception is a process of inference, integrating sensory inputs with prior expectations. However, little is known regarding the temporal dynamics of this integration. It has been proposed that expectation plays a role early in the perceptual process, by biasing early sensory processing. Alternatively, others suggest that expectations are integrated only at later, post-perceptual decision-making stages. The current study aimed to dissociate between these hypotheses. We exposed male and female human participants (N=24) to auditory cues predicting the likely direction of upcoming noisy moving dot patterns, while recording millisecond-resolved neural activity using magnetoencephalography (MEG). First, we found that participants’ reports of the moving dot directions were biased towards the direction predicted by the auditory cues. To investigate when expectations affected sensory representations, we used inverted encoding models to decode the direction represented in early sensory signals. Strikingly, the auditory cues modulated the direction represented in the MEG signal as early as 150ms after visual stimulus onset. This early neural modulation was related to perceptual effects of expectation: participants with a stronger perceptual bias towards the predicted direction also revealed a stronger reflection of the predicted direction in the MEG signal. For participants with this perceptual bias, a trial-by-trial correlation between decoded and perceived direction already emerged prior to visual stimulus onset (∼-150ms), suggesting that the pre-stimulus state of the visual cortex influences sensory processing. Together, these results suggest that prior expectations can influence perception by biasing early sensory processing, making expectation a fundamental component of the neural computations underlying perception.Significance statementPerception can be thought of as an inferential process in which our brains integrate sensory inputs with prior expectations to make sense of the world. This study investigated whether this integration occurs early or late in the process of perception. We exposed human participants to auditory cues which predicted the likely direction of visual moving dots, while recording neural activity with millisecond resolution using magnetoencephalography (MEG). Participants’ perceptual reports of the direction of the moving dots were biased towards the predicted direction. Additionally, the predicted direction modulated the neural representation of the moving dots just 150 ms after they appeared. This suggests that prior expectations affected sensory processing at very early stages, playing an integral role in the perceptual process.

scholarly journals Parietal Lobe Contribution to Mental Rotation Demonstrated with rTMS

2003 ◽  
Vol 15 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Irina M. Harris ◽  
Carlo Miniussi
Keyword(s):  
Mental Rotation ◽  
Neural Activity ◽  
Parietal Lobe ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Stimulus Onset ◽  
Visuomotor Transformations ◽  
Area 7 ◽  
Posterior Parietal ◽  
The Right ◽  
Posterior Parietal Lobe

A large number of imaging studies have identified a role for the posterior parietal lobe, in particular Brodmann's area 7 and the intraparietal sulcus (IPS), in mental rotation. Here we investigated whether neural activity in the posterior parietal lobe is essential for successful mental rotation performance by observing the effects of interrupting this activity during the execution of a mental rotation task. Repetitive transcranial magnetic stimulation (rTMS) was applied to posterior parietal locations estimated to overlie Brodmann's area 7 in the right and the left hemisphere, or to a posterior midline location (sham condition). In three separate experiments, rTMS (four pulses, 20 Hz) was delivered at these locations either 200–400, 400–600, or 600–800 msec after the onset of a mental rotation trial. Disrupting neural activity in the right parietal lobe interfered with task performance, but only when rTMS was delivered 400 to 600 msec after stimulus onset. Stimulation of the left parietal lobe did not reliably affect mental rotation performance at any of the time points investigated. The time-limited effect of rTMS was replicated in a fourth experiment that directly compared the effects of rTMS applied to the right parietal lobe either 200–400 or 400–600 msec into the mental rotation trial. The results indicate that the right superior posterior parietal lobe plays an essential role in mental rotation, consistent with its involvement in a variety of visuospatial and visuomotor transformations.

scholarly journals Neural Substrates Associated With Fatigue Symptom In Fibromyalgia

2022 ◽  
Author(s):  
Hung-Yu Liu ◽  
Pei-Lin Lee ◽  
Kun-Hsien Chou ◽  
Yen-Feng Wang ◽  
Shih-Pin Chen ◽  
...  
Keyword(s):  
Brain Mri ◽  
Temporal Cortex ◽  
Occipital Cortex ◽  
Neural Substrates ◽  
Inferior Temporal Cortex ◽  
Morphometry Analysis ◽  
Fatigue Severity ◽  
Subcortical Regions ◽  
The Right ◽  
Neural Signatures

Abstract Many patients with fibromyalgia (FM) experience fatigue, but the associated biological mechanisms have not been delineated. We aimed to investigate the neural signatures associated with fatigue severity in patients with FM using MRI. We consecutively recruited 138 patients with FM and collected their clinical profiles and brain-MRI data. We categorized the patients into 3 groups based on their fatigue severity. Using voxel-based morphometry analysis and trend analysis, we first identified neural structures showing volumetric changes associated with fatigue severity, and further explored their seed-to-voxel structural covariance networks (SCNs). Results showed decreased bilateral thalamic volumes were associated with higher severity of fatigue. There was a more widespread distribution of the thalamic SCNs to the frontal, parietal, subcortical, and limbic regions in patients with higher fatigue severity. In addition, increased right inferior temporal cortex volumes were associated with higher severity of fatigue. The right inferior temporal seed showed more SCNs distributions over the temporal cortex and a higher strength of SCNs to the bilateral occipital cortex in patients with higher fatigue severity. The thalamus and the right inferior temporal cortex as well as their altered interactions with cortical and subcortical regions comprise the neural signatures of fatigue in FM.

scholarly journals Transient neuronal suppression for exploitation of new sensory evidence

2020 ◽  
Author(s):  
Maxwell Shinn ◽  
Daeyeol Lee ◽  
John D. Murray ◽  
Hyojung Seo
Keyword(s):  
Decision Making ◽  
Neural Activity ◽  
Temporal Integration ◽  
Motor Preparation ◽  
Stimulus Onset ◽  
Frontal Eye Field ◽  
Perceptual Decision Making ◽  
Behavioral Studies ◽  
The Face ◽  
Sensory Evidence

AbstractIn noisy but stationary environments, decisions should be based on the temporal integration of sequentially sampled evidence. This strategy has been supported by many behavioral studies and is qualitatively consistent with neural activity in multiple brain areas. By contrast, decision-making in the face of non-stationary sensory evidence remains poorly understood. Here, we trained monkeys to identify the dominant color of a dynamically refreshed bicolor patch that becomes informative after a variable delay. Animals' behavioral responses were briefly suppressed after evidence changes, and many neurons in the frontal eye field displayed a corresponding dip in activity at this time, similar to that frequently observed after stimulus onset. Generalized drift-diffusion models revealed consistency of behavior and neural activity with brief suppression of motor output, but not with pausing or resetting of evidence accumulation. These results suggest that momentary arrest of motor preparation is an important component of dynamic perceptual decision making.

scholarly journals Mindfulness meditators show altered distributions of early and late neural activity markers of attention in a response inhibition task

2018 ◽  
Author(s):  
NW Bailey ◽  
G Freedman ◽  
K Raj ◽  
CM Sullivan ◽  
NC Rogasch ◽  
...  
Keyword(s):  
Sustained Attention ◽  
Response Inhibition ◽  
Neural Activity ◽  
Visual Information ◽  
Mindfulness Meditation ◽  
Occipital Cortex ◽  
Event Related Potential ◽  
Brain Areas ◽  
Eeg Recordings ◽  
The Right

AbstractAttention is a vital executive function, since other executive functions are largely dependent on it. Mindfulness meditation has been shown to enhance attention. However, the components of attention altered by meditation and the related neural activities are underexplored. In particular, the contributions of inhibitory processes and sustained attention are not well understood. Additionally, it is not clear whether improvements in attention are related to increases in the strength of typically activated brain areas, or the recruitment of additional or alternative brain areas. To address these points, 34 meditators were compared to 28 age and gender matched controls during electroencephalography (EEG) recordings of neural activity during a Go/Nogo response inhibition task. This task generates a P3 event related potential, which is related to response inhibition processes in Nogo trials, and attention processes across both trial types. Compared with controls, meditators were more accurate at responding to Go and Nogo trials. Meditators showed a more frontally distributed P3 to both Go and Nogo trials, suggesting more frontal involvement in sustained attention rather than activity specific to response inhibition. Unexpectedly, meditators also showed increased positivity over the right parietal cortex prior to visual information reaching the occipital cortex. Both results were positively related to increased accuracy across both groups. The results suggest that meditators have an increased capacity to modulate a range of neural processes in order to meet task requirements, including higher order processes, and sensory anticipation processes. This increased capacity may underlie the improved attentional function observed in mindfulness meditators.

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