Experience-based development of internal probabilistic representations in the primary visual cortex
34.11, Sunday, May 12, 2:30 - 4:15 pm, Royal Ballroom 1-3
József Fiser1, Cristina Savin2, Pietro Berkes3, Chiayu Chiu4, Máté Lengyel2; 1Department of Cognitive Science, Central European University, Budapest, Hungary, 2Computational & Biological Learning Lab, Department of Engineering, University of Cambridge, UK, 3Volen National Center for Complex Systems, Brandeis University, Waltham, MA, USA, 4Department of Neurobiology, Yale University, New Haven, CT, USA
The developmental increase in similarity between spontaneous (SA) and average stimulus-evoked activity (EA) in the primary visual cortex has been suggested to reflect a progressive adaptation of the animals internal model to the statistics of the environment, a hallmark of probabilistic computation in the cortex (Berkes et al, 2011). Still, this gradual adaptation could be due to genetically controlled developmental processes that have little to do with the animal's visual experience. To clarify this issue, we disrupted normal visual experience of N=16 ferrets of different ages (P30-P120) so that the animals perceived only diffuse light through their eyelids up to the moment of data collection. We measured neural activity from the superficial layers of V1 and compared SA and EA to those in normally reared controls. Furthermore, we extended the original analysis using maximum entropy models that control not only for the effects of single unit firing rates, but also for the population firing rate distribution which could confound measures of functional connectivity that we use as a measure of learning. The general statistics of V1 activity in lid-sutured animals developed very similarly to controls confirming that withholding natural visual experience does not abolish the general development of the visual system. However, while in the control animals SA was completely similar to EA evoked by natural stimuli and significantly less similar to EA evoked by noise, in lid-sutured animals this specificity to natural inputs disappeared, and the match between SA and EA for natural inputs became incomplete. Our novel analysis further confirmed that learning drives the increase of similarity between SA and EA in the oldest control adults. These results suggest that while intrinsic development of visual circuitry is controlled by developmental factors, learning from visual experience is crucial for the emergence of a complete match between SA and EA.