Neural response in V1 and V6 during free-viewing

• Grant number: 21/11277-0
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: October 01, 2021
• End date: September 30, 2023
• Field of knowledge: Biological Sciences - Physiology - General Physiology
• Agreement: Max Planck Society for the Advancement of Science
• Principal Investigator: Gustavo Rohenkohl
• Grantee: Richard Barana Block Moura
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 17/10429-5 - Long-range brain connectivity during active visual behavior, AP.JP

Abstract

Our knowledge about how the brain works is largely based on evidence obtained from highly controlled - but also very artificial - experiments. And in the area of vision this is no different. Since the seminal studies by Hubel and Wiesel in the late 1950s, the vast majority of experiments in vision have used fixation tasks, in which animals are required to keep their eyes fixed on a specific point for long periods (ofter seconds), while stimuli are presented at the periphery of the visual field. However, many animals - including humans and other primates - move their eyes 3 to 4 times per second, constantly bringing objects of interest to the center of the visual field. Therefore, to advance our understanding of visual processing, it is important that laboratory experiments get closer to natural viewing conditions. This project aims to understand how primary (V1) and superior (V6) visual areas respond to more naturalistic stimuli (i.e. movies) and viewing conditions (i.e. free-viewing). To this end, marmosets (Callithrix jacchus) freely explore videos of "natural" scenes - such as footage of landscapes or places. While watching the videos, neural activity data were recorded in three marmosets with two linear electrodes arrays (32 contacts each). In addition to neural recording, the animals' eyes were also recorded, this way we were able to define, at every instant, the place where the animals were looking in the visual scenes, and the regions of the scene present in the receptive field of the recorded neurons. Our goal is to investigate how the neural activity in areas V1 and V6 respond in these more naturalistic conditions. More specifically, we will use reverse correlation to investigate known phenomena in vision, such as history, pre-saccadic receptive field remapping and attentional gain. The results of this study will get us a step closer to understanding the neural mechanisms that enable vision, and more specifically the relationship between saccades and perception. (AU)