Prefrontal neurons of opposite spatial preference display distinct target selection dynamics.

Authors

Therese Lennert, Department of Neurology and Neurosurgery, Montreal Neurological Institute, Montreal, Quebec, H3A 2B4, Canada
Julio C Martinez-Trujillo, Department of Physiology, Faculty of Medicine, McGill University, Montreal, Quebec, H3G 1Y6 Canada

Document Type

Article

Publication Date

5-29-2013

Journal

The Journal of neuroscience : the official journal of the Society for Neuroscience

Volume

33

Issue

22

First Page

9520

Last Page

9529

URL with Digital Object Identifier

10.1523/JNEUROSCI.5156-12.2013

Abstract

Neurons in the primate dorsolateral prefrontal cortex (dlPFC) of one hemisphere are selective for the location of attended targets in both visual hemifields. Whether dlPFC neurons with selectivity for opposite hemifields directly compete with each other for target selection or instead play distinct roles during the allocation of attention remains unclear. We explored this issue by recording neuronal responses in the right dlPFC of two macaques while they allocated attention to a target in one hemifield and ignored a distracter on the opposite side. Forty-nine percent of the recorded neurons were target location selective. Neurons selective for contralateral targets (58%) systematically discriminated targets from distracters faster than neurons selective for ipsilateral targets (42%). Additionally, during trials in which sensory stimulation remained the same but both stimuli were task irrelevant and animals were required to detect a change in the color of a fixation spot, contralateral neurons still reliably discriminated the putative target from the distracter, whereas ipsilateral neurons did not. The latter result indicates that target-distracter discrimination by contralateral neurons could occur independently of discrimination by ipsilateral cells; thus, the two cell types may represent two different components of the prefrontal circuitry underlying the allocation of attention to targets in the presence of distracters. Moreover, the response of both contralateral and ipsilateral neurons to a single target was substantially reduced by the presence of a distracter in the contralateral hemifield. This result suggests that the presence of the distracter triggered inhibitory interactions within the dlPFC circuitry that suppressed responses to the attended target.