Beyond Fixation: detailed characterization of neural selectivity in free-viewing primates

Abstract

Virtually all vision studies use a fixation point to stabilize gaze, rendering stimuli on video screens fixed to retinal coordinates. This approach requires trained subjects, is limited by the accuracy of fixational eye movements, and ignores the role of eye movements in shaping visual input. To overcome these limitations, we developed a suite of hardware and software tools to study vision during natural behavior in untrained subjects. We show this approach recovers receptive fields and tuning properties of visual neurons from multiple cortical areas of marmoset monkeys. Combined with high-precision eye-tracking, it achieves sufficient resolution to recover the receptive fields of foveal V1 neurons. These findings demonstrate the power of free viewing to characterize neural response while simultaneously studying the dynamics of natural behavior.HighlightsWe introduce a free-viewing paradigm for studying neural mechanisms of visual processing during active visionReceptive fields (RFs) and neural selectivity in primary visual cortex (V1) and area MT can be extracted during free-viewing in minimally-trained subjectsNovel high-resolution eye tracking in this context supports detailed measurements of receptive fields in foveal V1