The lateral prefrontal cortex of primates encodes stimulus colors and their behavioral relevance during a match-to-sample task

Daniel Baldauf,Philipp Schwedhelm,Stefan Treue

doi:10.1038/s41598-020-61171-3

Abstract

The lateral prefrontal cortex of primates (lPFC) plays a central role in complex cognitive behavior, in decision-making as well as in guiding top-down attention. However, how and where in lPFC such behaviorally relevant signals are computed is poorly understood. We analyzed neural recordings from chronic microelectrode arrays implanted in lPFC region 8Av/45 of two rhesus macaques. The animals performed a feature match-to-sample task requiring them to match both motion and color information in a test stimulus. This task allowed to separate the encoding of stimulus motion and color from their current behavioral relevance on a trial-by-trial basis. We found that upcoming motor behavior can be robustly predicted from lPFC activity. In addition, we show that 8Av/45 encodes the color of a visual stimulus, regardless of its behavioral relevance. Most notably, whether a color matches the searched-for color can be decoded independent of a trial’s motor outcome and while subjects detect unique feature conjunctions of color and motion. Thus, macaque area 8Av/45 computes, among other task-relevant information, the behavioral relevance of visual color features. Such a signal is most critical for both the selection of responses as well as the deployment of top-down modulatory signals, like feature-based attention.

Highlights

The lateral prefrontal cortex of primates plays a central role in complex cognitive behavior, in decision-making as well as in guiding top-down attention
Recent electrophysiological studies indicate that task-relevant visual information are encoded by the lateral prefrontal cortex[1,2,3]
Local field potentials were recorded from region 8Av/45 of the lateral prefrontal cortex of two macaques performing a delayed match-to-sample task

Summary

Introduction

The lateral prefrontal cortex of primates (lPFC) plays a central role in complex cognitive behavior, in decision-making as well as in guiding top-down attention. Another line of research supports the view that the lPFC of macaques is involved in the preparation of an attentional signal[9,14,15,16] This signal is thought to be relayed to visual cortex, where it enhances the processing of behaviorally relevant information[17,18,19,20,21,22,23], which leads to behavioral advantages, e.g. higher task accuracy and/or faster reaction times for attended as compared to unattended stimuli[24]. In this report we investigate the activity of a prefrontal region directly anterior to the FEF of the macaque monkey, within the rostral part of area 8A36,37 The neuronal computations that are performed at the level of 8Av/45 may be related to stimulus perception, motor-planning or the computation of higher cognitive signals, like feature-based attention and decision-making

Methods

Results

Conclusion