scholarly journals Gamma synchronization between V1 and V4 improves behavioral performance

2018 ◽  
Author(s):  
Gustavo Rohenkohl ◽  
Conrado Arturo Bosman ◽  
Pascal Fries
Keyword(s):  
Phase Relation ◽  
Motor Behavior ◽  
Stimulus Change ◽  
Reaction Times ◽  
Local Power ◽  
Attention Task ◽  
Selective Visual Attention ◽  
Visual Areas ◽  
Communication Through Coherence ◽  
Higher Visual Areas

ABSTRACTMotor behavior is often driven by visual stimuli, relying on efficient feedforward communication from lower to higher visual areas. The Communication-through-Coherence hypothesis proposes that interareal communication depends on coherence at an optimal phase relation. While previous studies have linked effective communication to enhanced interareal coherence, it remains unclear, whether this interareal coherence occurs at an optimal phase relation that actually improves the stimulus transmission to behavioral report. We recorded local field potentials simultaneously from areas V1 and V4 of macaque monkeys performing a selective visual attention task, during which they reported changes of the attended stimulus. Gamma synchronization between V1 and V4, immediately preceding the stimulus change, predicted subsequent reaction times (RTs). Crucially, RTs were systematically slowed as trial-by-trial interareal gamma phase relations deviated from the phase relation at which V1 and V4 synchronized on average. These effects were specific to the attended stimulus and not due to local power or phase inside V1 or V4. We conclude that interareal gamma synchronization occurs at the optimal phase relation and thereby improves interareal communication and the effective transformation of sensory inputs into motor responses.

Spanning the Face Space

1998 ◽  
Vol 06 (03) ◽  
pp. 265-279 ◽  
Author(s):  
Shimon Edelman
Keyword(s):  
Computational Modeling ◽  
Object Representation ◽  
Receptive Fields ◽  
Computational Approach ◽  
Face Representation ◽  
Comprehensive Theory ◽  
Visual Areas ◽  
The Face ◽  
Higher Visual Areas ◽  
Perceptual Systems

The paper outlines a computational approach to face representation and recognition, inspired by two major features of biological perceptual systems: graded-profile overlapping receptive fields, and object-specific responses in the higher visual areas. This approach, according to which a face is ultimately represented by its similarities to a number of reference faces, led to the development of a comprehensive theory of object representation in biological vision, and to its subsequent psychophysical exploration and computational modeling.

scholarly journals Adaptive Integration in the Visual Cortex by Depressing Recurrent Cortical Circuits

2008 ◽  
Vol 20 (7) ◽  
pp. 1847-1872 ◽  
Author(s):  
Mark C. W. van Rossum ◽  
Matthijs A. A. van der Meer ◽  
Dengke Xiao ◽  
Mike W. Oram
Keyword(s):  
Visual Cortex ◽  
Physiological Data ◽  
High Contrast ◽  
Cortical Circuits ◽  
Response Latencies ◽  
Low Contrast ◽  
Visual Areas ◽  
Higher Visual Areas ◽  
Recurrent Connections

Neurons in the visual cortex receive a large amount of input from recurrent connections, yet the functional role of these connections remains unclear. Here we explore networks with strong recurrence in a computational model and show that short-term depression of the synapses in the recurrent loops implements an adaptive filter. This allows the visual system to respond reliably to deteriorated stimuli yet quickly to high-quality stimuli. For low-contrast stimuli, the model predicts long response latencies, whereas latencies are short for high-contrast stimuli. This is consistent with physiological data showing that in higher visual areas, latencies can increase more than 100 ms at low contrast compared to high contrast. Moreover, when presented with briefly flashed stimuli, the model predicts stereotypical responses that outlast the stimulus, again consistent with physiological findings. The adaptive properties of the model suggest that the abundant recurrent connections found in visual cortex serve to adapt the network's time constant in accordance with the stimulus and normalizes neuronal signals such that processing is as fast as possible while maintaining reliability.

Do Children With Focal Cerebellar Lesions Show Deficits in Shifting Attention?

2004 ◽  
Vol 92 (3) ◽  
pp. 1856-1866 ◽  
Author(s):  
B. Schoch ◽  
B. Gorissen ◽  
S. Richter ◽  
A. Ozimek ◽  
O. Kaiser ◽  
...  
Keyword(s):  
Reaction Times ◽  
Motor Deficits ◽  
Attention Task ◽  
Original Proposal ◽  
Cerebellar Damage ◽  
Mri Scans ◽  
Significant Impairment ◽  
Cerebellar Lesions ◽  
Degenerative Disorder ◽  
Shifting Attention

More recent findings suggest a possible role of the cerebellum in nonmotor functions. Disability of individuals with cerebellar damage in rapidly shifting attention is one frequently used example to support cerebellar involvement in mental skills. The original proposal was based on findings in five children with chronic surgical lesions of the cerebellum and a young adult with a degenerative disorder. The aim of the present study was to repeat Akshoomoff and Courchesne's initial findings in a larger group of children with focal cerebellar lesions. Ten children with cerebellar lesions and 10 age- and sex-matched controls were tested. Neocerebellar areas were affected in all children with cerebellar damage except one based on detailed analysis of MRI scans. Subjects had to perform a focus and a shift attention task. Two visual and two auditory stimuli were presented in a pseudorandom order. An ellipse and a high-pitched tone were presented less frequently than a circle and a low-pitched tone. Rare stimuli were presented at five different time intervals. In the focus tasks, subjects had to react to the same rare stimulus of one of the two modalities. In the shift task, subjects had to switch between the two rare stimuli. Motor deficits based on reaction times were small in cerebellar children compared with controls. The ability of target detection did not significantly differ in the children with cerebellar lesions compared with the control children in both the focus and the shift attention task. In particular, children with cerebellar damage showed no significant impairment in rapid (<2 s) shifts of attention. The present findings indicate that the cerebellum may be less critical in attention related processes than suggested previously.

scholarly journals Unique spatial integration in mouse primary visual cortex and higher visual areas

2019 ◽  
Author(s):  
Kevin A. Murgas ◽  
Ashley M. Wilson ◽  
Valerie Michael ◽  
Lindsey L. Glickfeld
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Spatial Information ◽  
Spatial Scales ◽  
Spatial Integration ◽  
Global Features ◽  
Wide Range ◽  
Visual Areas ◽  
Higher Visual Areas

AbstractNeurons in the visual system integrate over a wide range of spatial scales. This diversity is thought to enable both local and global computations. To understand how spatial information is encoded across the mouse visual system, we use two-photon imaging to measure receptive fields in primary visual cortex (V1) and three downstream higher visual areas (HVAs): LM (lateromedial), AL (anterolateral) and PM (posteromedial). We find significantly larger receptive field sizes and less surround suppression in PM than in V1 or the other HVAs. Unlike other visual features studied in this system, specialization of spatial integration in PM cannot be explained by specific projections from V1 to the HVAs. Instead, our data suggests that distinct connectivity within PM may support the area’s unique ability to encode global features of the visual scene, whereas V1, LM and AL may be more specialized for processing local features.

scholarly journals Can auditory warning signals normalize eye movements in children with ADHD?

2020 ◽  
Vol 29 (12) ◽  
pp. 1635-1644
Author(s):  
Johan Lundin Kleberg ◽  
Matilda A. Frick ◽  
Karin C. Brocki
Keyword(s):  
Reaction Times ◽  
Saccadic Latency ◽  
Temporary Increase ◽  
Typically Developing ◽  
Warning Signals ◽  
Attention Task ◽  
Children With Adhd ◽  
Hyperactivity Disorder ◽  
Latency Variability ◽  
Auditory Warning

Abstract Attenuated baseline arousal has been hypothesized to underlie symptoms of attention deficit/hyperactivity disorder (ADHD). A behavioral signature of reduced baseline arousal is an increased beneficiary effect of warning signals in reaction tasks. This paradoxical effect is believed to be caused by a temporary increase in arousal induced by warning signals. In a preregistered study, we tested the hypothesis that children with high levels of ADHD symptoms would be hyperresponsive to warning signals in a well-established visual attention task (the gap/overlap paradigm). Previous studies using this task have found slower and more variable saccadic reaction times in children with ADHD compared to typically developing children, suggesting that these eye movement metrics are candidate biomarkers. We examined 71 children, of which 1/3 had a diagnosis of ADHD, using both dimensional analyses and group comparisons. Previously reported findings of reduced saccadic latency and increased latency variability were replicated. Importantly, saccadic latency was normalized by auditory warning signals. Analyses of pupil dilation, a physiological index of arousal and locus coeruleus-noradrenergic activity, confirmed that warning signals led to enhanced arousal. Our findings are novel and contribute to our understanding of arousal and attention in ADHD and have implications for treatment and interventions.

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