Visual exposure enhances stimulus encoding and persistence in primary cortex

Abstract

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.

The functional role of oscillatory dynamics in neocortical circuits: a computational perspective

“…5B). Similar dynamic effects have been observed in the visual cortex in response to flashed stimuli [53], where this amplification of the input signal was hypothesized to be due to reverberating interactions among the nodes that eventually lead to the convergence towards a metastable stimulus-specific dynamic state. This state can be interpreted as the result of a highly parallelized search for the best match between sensory evidence and the priors installed by learning [2].…”

“…Thus, nodes activated by a particular stimulus become associated with one another by self-organizing interactions and form a cooperating, stimulusspecific assembly distinguished by synchronized and jointly enhanced responses. Such dynamics have also been observed in cortical networks [11, 53] and this has led to the binding by synchrony hypothesis (BBS) [29]. Moreover, such selective synchronization effects are to be expected if learning modifies recurrent connections according to a Hebbian correlation rule [2].…”

“…This state can be interpreted as the result of a highly parallelized search for the best match between sensory evidence and the priors installed by learning [2]. Such matching operations are the core of predictive coding strategies, and experiments in the visual cortex provide preliminary support for this notion [53]. Another interesting observation was that after learning, nodes initially activated by the stimulus exhibited synchronized oscillations whose amplitude increased as time elapsed.…”

Exploration of static functional connectivity and dynamic functional connectivity alterations in the primary visual cortex among patients with high myopia via seed-based functional connectivity analysis

“…The calcarine cortex and lingual gyrus are anatomical regions in the V1 that receive visual signals from the visual pathway, then transmit those signals to the higher visual cortex ( Beckmann et al, 2005 ). These rich dynamic properties exhibited by early visual neurons suggest that V1 does not encode the environment in a static manner; it exhibits rich spatial and temporal dynamic features ( Lazar et al, 2021 ). Huang et al (2018b) found that amplitude of low-frequency fluctuation values in the bilateral lingual gyrus were considerably lower in retinitis pigmentosa patients than in HCs.…”

More than the end: OFF response plasticity as a mnemonic signature of a sound’s behavioral salience

“…Together, ON-responsive and OFF-responsive neurons play a key role in enabling better contrast sensitivity and rapid information transfer for both increments and decrements of light intensity ( Schiller et al, 1986 ). OFF responses are essential to indicate changes in visual scenes ( Bair et al, 2002 ), and are modulated by size and spatial frequency ( Jansen et al, 2019 ; Lazar et al, 2021 ), as well as contrast over a range of luminance ( Rahimi-Nasrabadi et al, 2021 ).…”