Task-demands and audio-visual stimulus configurations modulate neural activity in the human thalamus

NeuroImage ◽  
2013 ◽  
Vol 66 ◽  
pp. 110-118 ◽  
Author(s):  
Björn Bonath ◽  
Sascha Tyll ◽  
Eike Budinger ◽  
Kerstin Krauel ◽  
Jens-Max Hopf ◽  
...  
Keyword(s):  
Visual Stimulus ◽  
Neural Activity ◽  
Task Demands ◽  
Human Thalamus

scholarly journals Neural activity in the human anterior thalamus during natural vision

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcin Leszczynski ◽  
Leila Chaieb ◽  
Tobias Staudigl ◽  
Simon Jonas Enkirch ◽  
Juergen Fell ◽  
...  
Keyword(s):  
Visual Stimulus ◽  
Neural Activity ◽  
Medial Temporal Lobe ◽  
Field Potential ◽  
Stimulus Presentation ◽  
Visual Exploration ◽  
Phase Reset ◽  
Saccade Onset ◽  
Human Thalamus ◽  
Natural Vision

AbstractIn natural vision humans and other primates explore environment by active sensing, using saccadic eye movements to relocate the fovea and sample different bits of information multiple times per second. Saccades induce a phase reset of ongoing neuronal oscillations in primary and higher-order visual cortices and in the medial temporal lobe. As a result, neuron ensembles are shifted to a common state at the time visual input propagates through the system (i.e., just after fixation). The extent of the brain’s circuitry that is modulated by saccades is not yet known. Here, we evaluate the possibility that saccadic phase reset impacts the anterior nuclei of the thalamus (ANT). Using recordings in the human thalamus of three surgical patients during natural vision, we found that saccades and visual stimulus onset both modulate neural activity, but with distinct field potential morphologies. Specifically, we found that fixation-locked field potentials had a component that preceded saccade onset. It was followed by an early negativity around 50 ms after fixation onset which is significantly faster than any response to visual stimulus presentation. The timing of these events suggests that the ANT is predictively modulated before the saccadic eye movement. We also found oscillatory phase concentration, peaking at 3–4 Hz, coincident with suppression of Broadband High-frequency Activity (BHA; 80–180 Hz), both locked to fixation onset supporting the idea that neural oscillations in these nuclei are reorganized to a low excitability state right after fixation onset. These findings show that during real-world natural visual exploration neural dynamics in the human ANT is influenced by visual and oculomotor events, which supports the idea that ANT, apart from their contribution to episodic memory, also play a role in natural vision.

The Faces of Development: A Review of Early Face Processing over Childhood

2004 ◽  
Vol 16 (8) ◽  
pp. 1426-1442 ◽  
Author(s):  
M. J. Taylor ◽  
M. Batty ◽  
R. J. Itier
Keyword(s):  
Young Children ◽  
Face Processing ◽  
Neural Activity ◽  
Task Demands ◽  
Inversion Effect ◽  
Age Related ◽  
Implicit And Explicit ◽  
Different Sources

The understanding of the adult proficiency in recognizing and extracting information from faces is still limited despite the number of studies over the last decade. Our knowledge on the development of these capacities is even more restricted, as only a handful of such studies exist. Here we present a combined reanalysis of four ERP studies in children from 4 to 15 years of age and adults (n = 424, across the studies), which investigated face processing in implicit and explicit tasks. We restricted these analyses to what was common across studies: early ERP components and upright face processing across all four studies and the inversion effect, investigated in three of the studies. These data demonstrated that processing faces implicates very rapid neural activity, even in young children— at the P1 component—with protracted age-related change in both P1 and N170, that were sensitive to the different task demands. Inversion produced latency and amplitude effects on the P1 from the youngest group, but on N170 only starting in mid childhood. These developmental data suggest that there are functionally different sources of the P1 and N170, related to the processing of different aspects of faces.

scholarly journals Stimulus dependence of theta rhythmic activity in primate V1 and its potential relevance for visual perception

2021 ◽  
Author(s):  
Prasakti Tenri Fanyiwi ◽  
Beshoy Agayby ◽  
Ricardo Kienitz ◽  
Marcus Haag ◽  
Michael C. Schmid
Keyword(s):  
Visual Perception ◽  
Visual Stimulus ◽  
Neural Activity ◽  
Temporal Dynamics ◽  
Reaction Times ◽  
Rhythmic Activity ◽  
Peak Frequency ◽  
Theta Oscillations ◽  
Theta Power ◽  
Fixational Eye Movements

AbstractA growing body of psychophysical research reports theta (3-8 Hz) rhythmic fluctuations in visual perception that are often attributed to an attentional sampling mechanism arising from theta rhythmic neural activity in mid- to high-level cortical association areas. However, it remains unclear to what extent such neuronal theta oscillations might already emerge at early sensory cortex like the primary visual cortex (V1), e.g. from the stimulus filter properties of neurons. To address this question, we recorded multi-unit neural activity from V1 of two macaque monkeys viewing a static visual stimulus with variable sizes, orientations and contrasts. We found that among the visually responsive electrode sites, more than 50 % showed a spectral peak at theta frequencies. Theta power varied with varying basic stimulus properties. Within each of these stimulus property domains (e.g. size), there was usually a single stimulus value that induced the strongest theta activity. In addition to these variations in theta power, the peak frequency of theta oscillations increased with increasing stimulus size and also changed depending on the stimulus position in the visual field. Further analysis confirmed that this neural theta rhythm was indeed stimulus-induced and did not arise from small fixational eye movements (microsaccades). When the monkeys performed a detection task of a target embedded in a theta-generating visual stimulus, reaction times also tended to fluctuate at the same theta frequency as the one observed in the neural activity. The present study shows that a highly stimulus-dependent neuronal theta oscillation can be elicited in V1 that appears to influence the temporal dynamics of visual perception.

scholarly journals Isolating Discriminant Neural Activity in the Presence of Eye Movements and Concurrent Task Demands

2017 ◽  
Vol 11 ◽  
Author(s):  
Jon Touryan ◽  
Vernon J. Lawhern ◽  
Patrick M. Connolly ◽  
Nima Bigdely-Shamlo ◽  
Anthony J. Ries
Keyword(s):  
Eye Movements ◽  
Neural Activity ◽  
Concurrent Task ◽  
Task Demands

Task demands modulate sustained and transient neural activity during visual-matching tasks

NeuroImage ◽  
2005 ◽  
Vol 25 (2) ◽  
pp. 511-519 ◽  
Author(s):  
E. Darcy Burgund ◽  
Heather M. Lugar ◽  
Bradley L. Schlaggar ◽  
Steven E. Petersen
Keyword(s):  
Neural Activity ◽  
Task Demands ◽  
Visual Matching

scholarly journals Learning to Control the Brain through Adaptive Closed-Loop Patterned Stimulation

2020 ◽  
Author(s):  
Sina Tafazoli ◽  
Camden J. MacDowell ◽  
Zongda Che ◽  
Katherine C. Letai ◽  
Cynthia Steinhardt ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Visual Stimulus ◽  
Neural Activity ◽  
Closed Loop ◽  
Neural Response ◽  
Learning System ◽  
Clinical Tool ◽  
Neuropsychiatric Diseases ◽  
Natural Response

AbstractStimulation of neural activity is an important scientific and clinical tool, causally testing hypotheses and treating neurodegenerative and neuropsychiatric diseases. However, current stimulation approaches cannot flexibly control the pattern of activity in populations of neurons. To address this, we developed an adaptive, closed-loop stimulation (ACLS) system that uses patterned, multi-site electrical stimulation to control the pattern of activity in a population of neurons. Importantly, ACLS is a learning system; it monitors the response to stimulation and iteratively updates the stimulation pattern to produce a specific neural response. In silico and in vivo experiments showed ACLS quickly learns to produce specific patterns of neural activity (∼15 minutes) and was robust to noise and drift in neural responses. In visual cortex of awake mice, ACLS learned electrical stimulation patterns that produced responses similar to the natural response evoked by visual stimuli. Similar to how repetition of a visual stimulus causes an adaptation in the neural response, the response to electrical stimulation was adapted when it was preceded by the associated visual stimulus. Altogether, our results show ACLS can learn, in real-time, to generate specific patterns of neural activity, providing a framework for using closed-loop learning to control neural activity.

scholarly journals Direction-selective motion discrimination by traveling waves in visual cortex

2020 ◽  
Author(s):  
Stewart Heitmann ◽  
G. Bard Ermentrout
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Primary Visual Cortex ◽  
Visual Stimulus ◽  
Traveling Waves ◽  
Neural Activity ◽  
Time Delays ◽  
Neural Mechanism ◽  
Neural Responses ◽  
Transmission Delays

AbstractThe majority of neurons in primary visual cortex respond selectively to bars of light that have a specific orientation and move in a specific direction. The spatial and temporal responses of such neurons are non-separable. How neurons accomplish that computational feat without resort to explicit time delays is unknown. We propose a novel neural mechanism whereby visual cortex computes non-separable responses by generating endogenous traveling waves of neural activity that resonate with the space-time signature of the visual stimulus. The spatiotemporal characteristics of the response are defined by the local topology of excitatory and inhibitory lateral connections in the cortex. We simulated the interaction between endogenous traveling waves and the visual stimulus using spatially distributed populations of excitatory and inhibitory neurons with Wilson-Cowan dynamics and inhibitory-surround coupling. Our model reliably detected visual gratings that moved with a given speed and direction provided that we incorporated neural competition to suppress false motion signals in the opposite direction. The findings suggest that endogenous traveling waves in visual cortex can impart direction-selectivity on neural responses without resort to explicit time delays. They also suggest a functional role for motion opponency in eliminating false motion signals.Author summaryIt is well established that the so-called ‘simple cells’ of the primary visual cortex respond preferentially to oriented bars of light that move across the visual field with a particular speed and direction. The spatiotemporal responses of such neurons are said to be non-separable because they cannot be constructed from independent spatial and temporal neural mechanisms. Contemporary theories of how neurons compute non-separable responses typically rely on finely tuned transmission delays between signals from disparate regions of the visual field. However the existence of such delays is controversial. We propose an alternative neural mechanism for computing non-separable responses that does not require transmission delays. It instead relies on the predisposition of the cortical tissue to spontaneously generate spatiotemporal waves of neural activity that travel with a particular speed and direction. We propose that the endogenous wave activity resonates with the visual stimulus to elicit direction-selective neural responses to visual motion. We demonstrate the principle in computer models and show that competition between opposing neurons robustly enhances their ability to discriminate between visual gratings that move in opposite directions.

scholarly journals Carving the Clock at Its Component Joints: Neural Bases for Interval Timing

2010 ◽  
Vol 104 (1) ◽  
pp. 160-168 ◽  
Author(s):  
Elaine B. Wencil ◽  
H. Branch Coslett ◽  
Geoffrey K. Aguirre ◽  
Anjan Chatterjee
Keyword(s):  
Time Perception ◽  
Visual Stimulus ◽  
Neural Activity ◽  
Task Difficulty ◽  
Supplementary Motor Area ◽  
Temporal Discrimination ◽  
Internal Clock ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
The Subject

Models of time perception often describe an “internal clock” that involves at least two components: an accumulator and a comparator. We used functional magnetic resonance imaging to test the hypothesis that distinct distributed neural networks mediate these components of time perception. Subjects performed a temporal discrimination task that began with a visual stimulus (S1) that varied parametrically in duration of presentation. A varying interstimulus interval was followed by a second visual stimulus (S2). After the S2 offset, the subject indicated whether S2 was longer or shorter than S1. We reasoned that neural activity that correlated with S1 duration would represent accumulator networks. We also reasoned that neural activity that correlated with the difficulty of comparisons for each paired-judgment would represent comparator networks. Using anatomically defined regions of interest, we found duration of S1 significantly correlated with left inferior frontal, supplementary motor area (SMA) and superior temporal regions. Furthermore, task difficulty correlated with activity within bilateral inferior frontal gyri. Therefore accumulator and comparator functioning of the internal clock are mediated by distinct as well as partially overlapping neural regions.

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 Mindfulness meditation alters neural activity underpinning working memory during tactile distraction

2019 ◽  
Author(s):  
Michael Yufeng Wang ◽  
Gabrielle Freedman ◽  
Kavya Raj ◽  
Bernadette Mary Fitzgibbon ◽  
Caley Sullivan ◽  
...  
Keyword(s):  
Working Memory ◽  
Neural Activity ◽  
Tactile Stimulation ◽  
Mindfulness Meditation ◽  
Brain Activity ◽  
Alpha Activity ◽  
Task Demands ◽  
Attentional Processes ◽  
Attentional Function ◽  
Tactile Stimuli

AbstractEvidence suggests that mindfulness meditation (MM) improves selective attention and reduces distractibility by enhancing top-down neural modulation. Altered P300 and alpha neural activity from MM have been identified and may reflect the neural changes that underpin these improvements. Given the proposed role of alpha activity in supressing processing of task-irrelevant information, it is theorised that altered alpha activity may underlie increased availability of neural resources in meditators. The present study investigated attentional function in meditators using a cross-modal study design, examining the P300 during working memory (WM) and alpha activity during concurrent distracting tactile stimuli. Thirty-three meditators and 27 healthy controls participated in the study. Meditators showed a more frontal distribution of P300 neural activity following WM stimuli (p = 0.005, η² = 0.060) and more modulation of alpha activity at parietal-occipital regions between single (tactile stimulation only) and dual task demands (tactile stimulation plus WM task) (p < 0.001, η² = 0.065). Additionally, meditators performed more accurately than controls (p = 0.038, η² = 0.067). The altered distribution of neural activity concurrent with improved WM performance suggests greater attentional resources dedicated to task related functions such as WM in meditators. Thus, meditation-related neural changes are likely multi-faceted involving both altered distribution and also amplitudes of brain activity, enhancing attentional processes depending on task requirements.

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