scholarly journals Visual exposure enhances stimulus encoding and persistence in primary cortex

2021 ◽  
Vol 118 (43) ◽  
pp. e2105276118
Author(s):  
Andreea Lazar ◽  
Christopher Lewis ◽  
Pascal Fries ◽  
Wolf Singer ◽  
Danko Nikolic
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Stimulus Presentation ◽  
Projection Methods ◽  
Recurrent Network ◽  
Neuronal Population ◽  
Neuronal Populations ◽  
Visual Exposure ◽  
Early Visual Cortex ◽  
Low Dimensional

The brain adapts to the sensory environment. For example, simple sensory exposure can modify the response properties of early sensory neurons. How these changes affect the overall encoding and maintenance of stimulus information across neuronal populations remains unclear. We perform parallel recordings in the primary visual cortex of anesthetized cats and find that brief, repetitive exposure to structured visual stimuli enhances stimulus encoding by decreasing the selectivity and increasing the range of the neuronal responses that persist after stimulus presentation. Low-dimensional projection methods and simple classifiers demonstrate that visual exposure increases the segregation of persistent neuronal population responses into stimulus-specific clusters. These observed refinements preserve the representational details required for stimulus reconstruction and are detectable in postexposure spontaneous activity. Assuming response facilitation and recurrent network interactions as the core mechanisms underlying stimulus persistence, we show that the exposure-driven segregation of stimulus responses can arise through strictly local plasticity mechanisms, also in the absence of firing rate changes. Our findings provide evidence for the existence of an automatic, unguided optimization process that enhances the encoding power of neuronal populations in early visual cortex, thus potentially benefiting simple readouts at higher stages of visual processing.

scholarly journals Visual exposure optimizes stimulus encoding in primary visual cortex

2018 ◽  
Author(s):  
Andreea Lazar ◽  
Chris Lewis ◽  
Pascal Fries ◽  
Wolf Singer ◽  
Danko Nikolić
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Neuronal Response ◽  
Extended Period ◽  
Sensory Cells ◽  
Neuronal Populations ◽  
Visual Exposure ◽  
Early Visual Cortex ◽  
Sensory Cortices

SummarySensory exposure alters the response properties of individual neurons in primary sensory cortices. However, it remains unclear how these changes affect stimulus encoding by populations of sensory cells. Here, recording from populations of neurons in cat primary visual cortex, we demonstrate that visual exposure enhances stimulus encoding and discrimination. We find that repeated presentation of brief, high-contrast shapes results in a stereotyped, biphasic population response consisting of a short-latency transient, followed by a late and extended period of reverberatory activity. Visual exposure selectively improves the stimulus specificity of the reverberatory activity, by increasing the magnitude and decreasing the trial-to-trial variability of the neuronal response. Critically, this improved stimulus encoding is distributed across the population and depends on precise temporal coordination. Our findings provide evidence for the existence of an exposure-driven optimization process that enhances the encoding power of neuronal populations in early visual cortex, thus potentially benefiting simple readouts at higher stages of visual processing.

scholarly journals Low rank mechanisms underlying flexible visual representations

2020 ◽  
Vol 117 (47) ◽  
pp. 29321-29329 ◽  
Author(s):  
Douglas A. Ruff ◽  
Cheng Xue ◽  
Lily E. Kramer ◽  
Faisal Baqai ◽  
Marlene R. Cohen
Keyword(s):  
Visual Cortex ◽  
Cognitive Processes ◽  
Task Switching ◽  
Visual Processing ◽  
Neuronal Population ◽  
Low Rank ◽  
Visual Neurons ◽  
Sensory Stimuli ◽  
Neuronal Populations ◽  
Wide Range

Neuronal population responses to sensory stimuli are remarkably flexible. The responses of neurons in visual cortex have heterogeneous dependence on stimulus properties (e.g., contrast), processes that affect all stages of visual processing (e.g., adaptation), and cognitive processes (e.g., attention or task switching). Understanding whether these processes affect similar neuronal populations and whether they have similar effects on entire populations can provide insight into whether they utilize analogous mechanisms. In particular, it has recently been demonstrated that attention has low rank effects on the covariability of populations of visual neurons, which impacts perception and strongly constrains mechanistic models. We hypothesized that measuring changes in population covariability associated with other sensory and cognitive processes could clarify whether they utilize similar mechanisms or computations. Our experimental design included measurements in multiple visual areas using four distinct sensory and cognitive processes. We found that contrast, adaptation, attention, and task switching affect the variability of responses of populations of neurons in primate visual cortex in a similarly low rank way. These results suggest that a given circuit may use similar mechanisms to perform many forms of modulation and likely reflects a general principle that applies to a wide range of brain areas and sensory, cognitive, and motor processes.

Two distinct neural mechanisms in early visual cortex determine subsequent visual processing

Cortex ◽  
2014 ◽  
Vol 59 ◽  
pp. 1-11 ◽  
Author(s):  
Christianne Jacobs ◽  
Tom A. de Graaf ◽  
Alexander T. Sack
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Neural Mechanisms ◽  
Early Visual Cortex

scholarly journals Defining the Units of Competition: Influences of Perceptual Organization on Competitive Interactions in Human Visual Cortex

2010 ◽  
Vol 22 (11) ◽  
pp. 2417-2426 ◽  
Author(s):  
Stephanie A. McMains ◽  
Sabine Kastner
Keyword(s):  
Visual Cortex ◽  
Perceptual Organization ◽  
Visual Processing ◽  
Perceptual Grouping ◽  
Neural Representation ◽  
Competitive Interactions ◽  
Illusory Figure ◽  
Processing Stream ◽  
Neural Processes ◽  
Early Visual Cortex

Multiple stimuli that are present simultaneously in the visual field compete for neural representation. At the same time, however, multiple stimuli in cluttered scenes also undergo perceptual organization according to certain rules originally defined by the Gestalt psychologists such as similarity or proximity, thereby segmenting scenes into candidate objects. How can these two seemingly orthogonal neural processes that occur early in the visual processing stream be reconciled? One possibility is that competition occurs among perceptual groups rather than at the level of elements within a group. We probed this idea using fMRI by assessing competitive interactions across visual cortex in displays containing varying degrees of perceptual organization or perceptual grouping (Grp). In strong Grp displays, elements were arranged such that either an illusory figure or a group of collinear elements were present, whereas in weak Grp displays the same elements were arranged randomly. Competitive interactions among stimuli were overcome throughout early visual cortex and V4, when elements were grouped regardless of Grp type. Our findings suggest that context-dependent grouping mechanisms and competitive interactions are linked to provide a bottom–up bias toward candidate objects in cluttered scenes.

scholarly journals Retraction Notice to: Perceptual load affects spatial tuning of neuronal populations in human early visual cortex

2020 ◽  
Vol 30 (23) ◽  
pp. 4814
Author(s):  
Benjamin de Haas ◽  
D. Samuel Schwarzkopf ◽  
Elaine J. Anderson ◽  
Geraint Rees
Keyword(s):  
Visual Cortex ◽  
Perceptual Load ◽  
Neuronal Populations ◽  
Spatial Tuning ◽  
Early Visual Cortex ◽  
Retraction Notice

scholarly journals Emergence of transformation-tolerant representations of visual objects in rat lateral extrastriate cortex

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Sina Tafazoli ◽  
Houman Safaai ◽  
Gioia De Franceschi ◽  
Federica Bianca Rosselli ◽  
Walter Vanzella ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Visual Information ◽  
Neuronal Firing ◽  
Extrastriate Cortex ◽  
Level Energy ◽  
Object Processing ◽  
Neuronal Populations ◽  
Visual Objects ◽  
Extrastriate Areas

Rodents are emerging as increasingly popular models of visual functions. Yet, evidence that rodent visual cortex is capable of advanced visual processing, such as object recognition, is limited. Here we investigate how neurons located along the progression of extrastriate areas that, in the rat brain, run laterally to primary visual cortex, encode object information. We found a progressive functional specialization of neural responses along these areas, with: (1) a sharp reduction of the amount of low-level, energy-related visual information encoded by neuronal firing; and (2) a substantial increase in the ability of both single neurons and neuronal populations to support discrimination of visual objects under identity-preserving transformations (e.g., position and size changes). These findings strongly argue for the existence of a rat object-processing pathway, and point to the rodents as promising models to dissect the neuronal circuitry underlying transformation-tolerant recognition of visual objects.

Unconscious and Conscious Processing of Color Rely on Activity in Early Visual Cortex: A TMS Study

2012 ◽  
Vol 24 (4) ◽  
pp. 819-829 ◽  
Author(s):  
Henry Railo ◽  
Niina Salminen-Vaparanta ◽  
Linda Henriksson ◽  
Antti Revonsuo ◽  
Mika Koivisto
Keyword(s):  
Visual Cortex ◽  
Time Windows ◽  
Single Pulse ◽  
Stimulus Presentation ◽  
Stimulus Onset ◽  
Forced Choice ◽  
Conscious Perception ◽  
Unconscious Processing ◽  
Early Visual Cortex ◽  
Chromatic Processing

Chromatic information is processed by the visual system both at an unconscious level and at a level that results in conscious perception of color. It remains unclear whether both conscious and unconscious processing of chromatic information depend on activity in the early visual cortex or whether unconscious chromatic processing can also rely on other neural mechanisms. In this study, the contribution of early visual cortex activity to conscious and unconscious chromatic processing was studied using single-pulse TMS in three time windows 40–100 msec after stimulus onset in three conditions: conscious color recognition, forced-choice discrimination of consciously invisible color, and unconscious color priming. We found that conscious perception and both measures of unconscious processing of chromatic information depended on activity in early visual cortex 70–100 msec after stimulus presentation. Unconscious forced-choice discrimination was above chance only when participants reported perceiving some stimulus features (but not color).

scholarly journals Early cross-modal interactions and adult human visual cortical plasticity revealed by binocular rivalry

2015 ◽  
Author(s):  
Claudia Lunghi
Keyword(s):  
Visual Cortex ◽  
Binocular Rivalry ◽  
Visual Processing ◽  
Cortical Plasticity ◽  
Monocular Deprivation ◽  
Homeostatic Plasticity ◽  
Multisensory Perception ◽  
Modal Interactions ◽  
Early Visual Cortex ◽  
Visual Cortical

In this research binocular rivalry is used as a tool to investigate different aspects of visual and multisensory perception. Several experiments presented here demonstrated that touch specifically interacts with vision during binocular rivalry and that the interaction likely occurs at early stages of visual processing, probably V1 or V2. Another line of research also presented here demonstrated that human adult visual cortex retains an unexpected high degree of experience-dependent plasticity by showing that a brief period of monocular deprivation produced important perceptual consequences on the dynamics of binocular rivalry, reflecting a homeostatic plasticity. In summary, this work shows that binocular rivalry is a powerful tool to investigate different aspects of visual perception and can be used to reveal unexpected properties of early visual cortex.

scholarly journals The geometry of masking in neural populations

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Dario L. Ringach
Keyword(s):  
Visual Cortex ◽  
Cortical Neurons ◽  
Dimensional Space ◽  
Geometric Analysis ◽  
Geometric Approach ◽  
Population Level ◽  
Contextual Modulation ◽  
Neural Populations ◽  
Early Visual Cortex ◽  
Low Dimensional

Abstract The normalization model provides an elegant account of contextual modulation in individual neurons of primary visual cortex. Understanding the implications of normalization at the population level is hindered by the heterogeneity of cortical neurons, which differ in the composition of their normalization pools and semi-saturation constants. Here we introduce a geometric approach to investigate contextual modulation in neural populations and study how the representation of stimulus orientation is transformed by the presence of a mask. We find that population responses can be embedded in a low-dimensional space and that an affine transform can account for the effects of masking. The geometric analysis further reveals a link between changes in discriminability and bias induced by the mask. We propose the geometric approach can yield new insights into the image processing computations taking place in early visual cortex at the population level while coping with the heterogeneity of single cell behavior.

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