Active Vision in Marmosets: A Model System for Visual Neuroscience

TLDR

The common marmoset, a small-bodied New World primate, has been used for visual, auditory, and vocal neurophysiology, yet it is unknown whether head‑restrained marmosets can perform visual tasks. The study aims to determine whether marmosets can perform visual tasks under head restraint. The authors compared head‑fixed marmosets to macaques in free‑viewing saccade metrics and trained marmosets to fixate a central point for liquid reward using behavioral conditioning. Two marmosets successfully fixated a central point, ignored peripheral flashing stimuli, and performed an orientation discrimination task with a saturating psychometric function and shorter reaction times for easier discriminations, indicating that the marmoset is a viable model for active vision studies.

Abstract

The common marmoset (Callithrix jacchus), a small-bodied New World primate, offers several advantages to complement vision research in larger primates. Studies in the anesthetized marmoset have detailed the anatomy and physiology of their visual system (Rosa et al., 2009) while studies of auditory and vocal processing have established their utility for awake and behaving neurophysiological investigations (Lu et al., 2001a,b; Eliades and Wang, 2008a,b; Osmanski and Wang, 2011; Remington et al., 2012). However, a critical unknown is whether marmosets can perform visual tasks under head restraint. This has been essential for studies in macaques, enabling both accurate eye tracking and head stabilization for neurophysiology. In one set of experiments we compared the free viewing behavior of head-fixed marmosets to that of macaques, and found that their saccadic behavior is comparable across a number of saccade metrics and that saccades target similar regions of interest including faces. In a second set of experiments we applied behavioral conditioning techniques to determine whether the marmoset could control fixation for liquid reward. Two marmosets could fixate a central point and ignore peripheral flashing stimuli, as needed for receptive field mapping. Both marmosets also performed an orientation discrimination task, exhibiting a saturating psychometric function with reliable performance and shorter reaction times for easier discriminations. These data suggest that the marmoset is a viable model for studies of active vision and its underlying neural mechanisms.