Head-mounted optical imaging and optogenetic stimulation system for use in behaving primates

Summary

Advances in optical technology have revolutionized studies of brain function in freely behaving mice. Here, we describe an optical imaging and stimulation device for use in primates that easily attaches to an intracranial chamber. It consists of affordable commercially available or 3D-printed components: a monochromatic camera, a small standard lens, a wireless μLED stimulator powered by an induction coil, and an LED array for illumination. We show that the intrinsic imaging performance of this device is comparable to a standard benchtop system in revealing the functional organization of the visual cortex for awake macaques in a primate chair or under anesthesia. Imaging revealed neural modulatory effects of wireless focal optogenetic stimulation aimed at identified functional domains. With a 1 to 2 cm field of view, 100× larger than previously used in primates without head restraint, our device permits widefield optical imaging and optogenetic stimulation for ethological studies in primates.

Graphical abstract

Highlights

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  Chamber-mounted imaging and optical stimulation device for non-head-fixed macaques

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  Low cost, easy to mount, widefield (cm-size) mini camera and wireless μLED stimulator

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  Provides good mesoscale functional maps in areas V1, V2, and V4

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  Images cortical response during optogenetic stimulation of functional domains

Motivation

Nonhuman primates remain our best animal model for studying the neural underpinnings of human behavior. Our device is an initial step toward developing a system for widefield optical imaging and stimulation in freely moving nonhuman primates. Such systems have been used to study naturalistic behaviors in rodents and other small animals, but the size of the primate brain offers unique challenges in imaging cortical areas that we address in this study.

Abstract

To study naturalistic behaviors in monkeys, Zaraza et al. develop a head-mounted imaging and wireless optogenetic stimulation device. It is small, easy to mount, and low cost. They present images of mesoscale functional domains in visual areas V1, V2, and V4 and demonstrate evidence of spatiotemporal cortical modulation induced by focal optogenetic stimulation.