Chapter 22 – The Marmoset as a Model for Visual Neuroscience
The Common Marmoset in Captivity and Biomedical Research
Jude F. Mitchell, David A. Leopold
American College of Laboratory Animal Medicine 2019, Pages 377-413
Abstract
The common marmoset (Callithrix jacchus) has been valuable as a primate model in biomedical research. Interest in this species has grown recently, in part due to the successful demonstration of transgenic marmosets. Here we examine the prospects of the marmoset model for visual neuroscience research, adopting a comparative framework to place the marmoset within a broader evolutionary context. We begin by reviewing how the eye, brain, and visually guided behaviors of primates differ from those of other mammals. We then focus on the marmoset, comparing and contrasting features of its visual system and behavior with the better-studied macaque. We consider experimental advantages and challenges of the marmoset model along with its potential to complement visual neuroscience studies in the macaque and the mouse. The marmoset’s small brain bears most of the organizational features of other primates, and its smooth surface offers practical advantages over the macaque for areal mapping, laminar electrode penetration, and two-photon and optical imaging. Initial reports demonstrate that physiological responses to both simple and complex visual stimuli resemble those commonly observed in the macaque. Behaviorally, marmosets are more limited in their ability to perform regimented psychophysical tasks than macaques, but they do readily accept the head restraint that is necessary for accurate eye tracking and neurophysiology, and can be trained to perform simple visual discriminations. The natural gaze behavior of marmosets closely resembles those of macaques and humans, with a tendency to focus on objects of social interest including faces. Their immaturity at birth and routine twinning makes them ideal for the study of postnatal visual development. We argue that these experimental factors, together with the theoretical advantages inherent in comparing anatomy, physiology, and behavior across related species, make the marmoset an excellent model for visual neuroscience, offering new and complementary avenues to investigate the biology of human visual cognition.