Project Details
Projekt Print View

Fading memory in the visual cortex of awake monkeys

Applicant Dr. Danko Nikolic
Subject Area Cognitive, Systems and Behavioural Neurobiology
Term from 2012 to 2015
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 232383759
 
Final Report Year 2018

Final Report Abstract

In the present study, we investigated the impact of repetitive visual exposure on the distributed dynamics of populations of neurons, recorded simultaneously from cat area 17. We expanded on previous studies on exposure-triggered learning, by considering stimuli that were less redundant than oriented bars and gratings from an information perspective and thus better suited to capture aspects of distributed coding. In particular, we asked how brief, repetitive exposure to a large set of abstract visual shapes (alphabet letters and digits), affected the capacity of hypothetical downstream decoders to discriminate between different stimuli based on the reverberatory responses of primary visual cortex populations. We employed brief stimulus presentations at high contrast, which have previously been shown to induce strong recurrent activity. We showed that the performance of a Bayesian classifier, trained to predict stimulus identity based on short segments of data, was improved by stimulus exposure over the course of a recording session: early trials had lower performance scores than late trials. To identify the mechanisms underlying these changes, we sought neuronal correlates of the improvement in classification performance by characterizing the population firing rates, the firing rate variabilities, the correlation structures between pairs of neurons and the selectivity of low-dimensional stimulus representations extracted via principal component analyses. Finally, we investigated the impacts of sensory experiences on stimulus encoding during the sequential presentations of multiple visual shapes.

Publications

 
 

Additional Information

Textvergrößerung und Kontrastanpassung