Document Type
Article
Publication Date
11-13-2019
Journal
The Journal of neuroscience : the official journal of the Society for Neuroscience
Volume
39
Issue
46
First Page
9197
Last Page
9206
URL with Digital Object Identifier
10.1523/JNEUROSCI.1786-19.2019
Abstract
Copyright © 2019 the authors. The frontal eye field (FEF) is a critical region for the deployment of overt and covert spatial attention. Although investigations in the macaque continue to provide insight into the neural underpinnings of the FEF, due to its location within a sulcus, the macaque FEF is virtually inaccessible to electrophysiological techniques such as high-density and laminar recordings. With a largely lissencephalic cortex, the common marmoset (Callithrix jacchus) is a promising alternative primate model for studying FEF microcircuitry. Putative homologies have been established with the macaque FEF on the basis of cytoarchitecture and connectivity; however, physiological investigation in awake, behaving marmosets is necessary to physiologically locate this area. Here, we addressed this gap using intracortical microstimulation in a broad range of frontal cortical areas in three adult marmosets (two males, one female). We implanted marmosets with 96-channel Utah arrays and applied microstimulation trains while they freely viewed video clips. We evoked short-latency fixed vector saccades at low currents (<50 >μA) in areas 45, 8aV, 8C, and 6DR. We observed a topography of saccade direction and amplitude consistent with findings in macaques and humans: small saccades in ventrolateral FEF and large saccades combined with contralateral neck and shoulder movements encoded in dorsomedial FEF. Our data provide compelling evidence supporting homology between marmoset and macaque FEF and suggest that the marmoset is a useful primate model for investigating FEF microcircuitry and its contributions to oculomotor and cognitive functions.SIGNIFICANCE STATEMENT The frontal eye field (FEF) is a critical cortical region for overt and covert spatial attention. The microcircuitry of this area remains poorly understood because in the macaque, the most commonly used model, it is embedded within a sulcus and is inaccessible to modern electrophysiological and imaging techniques. The common marmoset is a promising alternative primate model due to its lissencephalic cortex and potential for genetic manipulation. However, evidence for homologous cortical areas in this model remains limited and unclear. Here, we applied microstimulation in frontal cortical areas in marmosets to physiologically identify FEF. Our results provide compelling evidence for an FEF in the marmoset and suggest that the marmoset is a useful model for investigating FEF microcircuitry.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Notes
Copyright: 2019, the Authors. This article is available to copy, distribute, or display under the terms of the Creative Commons Attribution 4.0 International License (CC-BY).
This article was published as:
Functional Localization of the Frontal Eye Fields in the Common Marmoset Using Microstimulation. Janahan Selvanayagam, Kevin D. Johnston, David J. Schaeffer, Lauren K. Hayrynen, Stefan Everling. Journal of Neuroscience 13 November 2019, 39 (46) 9197-9206; DOI: 10.1523/JNEUROSCI.1786-19.2019