Unilateral deactivation of macaque dorsolateral prefrontal cortex induces biases in stimulus selection

Authors

Kevin Johnston, Brain and Mind Institute, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; Department of Psychology, University of Western Ontario, London, Ontario, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada; and kjohnst9@uwo.ca.
Stephen G. Lomber, Brain and Mind Institute, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; Department of Psychology, University of Western Ontario, London, Ontario, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada; and.
Stefan Everling, Brain and Mind Institute, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; Department of Psychology, University of Western Ontario, London, Ontario, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada; and Robarts Research Institute, London, Ontario, Canada.

Document Type

Article

Publication Date

3-1-2016

Journal

Journal of neurophysiology

Volume

115

Issue

3

First Page

1468

Last Page

76

URL with Digital Object Identifier

10.1152/jn.00563.2015

Abstract

Following unilateral brain injury, patients are often unable to detect a stimulus presented in the contralesional field when another is presented simultaneously ipsilesionally. This phenomenon has been referred to as extinction and has been conceptualized as a deficit in selective attention. Although most commonly observed following damage to posterior parietal areas, extinction has been observed following lesions of prefrontal cortex (PFC) in both humans and nonhuman primates. To date, most studies in nonhuman primates have examined lesions of multiple PFC subregions, including the frontal eye fields (FEF). Theoretical accounts of attentional disturbances from human patients, however, also implicate other PFC areas, including the middle frontal gyrus. Here, we investigated the effects of deactivating PFC areas anterior to the FEF on stimulus selection using a free-choice task. Macaque monkeys were presented with two peripheral stimuli appearing either simultaneously, or at varying stimulus onset asynchronies, and their performance was evaluated during unilateral cryogenic deactivation of part of dorsolateral prefrontal cortex or the cortex lining the caudal principal sulcus, the likely homologue of the human middle frontal gyrus. A decreased proportion of saccades was made to stimuli presented in the hemifield contralateral to the deactivated PFC. We also observed increases in reaction times to contralateral stimuli and decreases for stimuli presented in the hemifield ipsilateral to the deactivated hemisphere. In both cases, these results were greatest when both PFC subregions were deactivated. These findings demonstrate that selection biases result from PFC deactivation and support a role of dorsolateral prefrontal subregions anterior to FEF in stimulus selection.