Dorsolateral prefrontal cortex is a key cortical locus for perceptual decisions

Perceptual decision-making involves combining sensory evidence with available choices to arrive at an appropriate action to report the choice. When sensory evidence and potential actions to report choice are simultaneously available, neural activity in dorsal premotor (PMd) and lateral intraparietal (LIP) cortices covary with sensory evidence and choice. However, when sensory evidence and possible actions are separated in time, PMd and LIP show action selection related responses and only when the stimulus-response relationship is apparent. Thus, these areas are largely involved in action selection. However, in many settings, evidence must be held in working memory before possible actions are known. How does decision-making occur if sensory evidence and potential actions to report choice are not simultaneously represented? Is there a brain area that supports these decision-related computations in such settings?

Here, we trained a monkey in a perceptual decision-making task that separated the deliberation on sensory evidence from the action selection process by a working memory delay. The monkey initially viewed a central red-green checkerboard for 900 ms. After a variable working memory delay , two targets, red and green, appeared and the goal was to touch the target that matched the dominant color in the checkerboard. While the monkey performed this task, we recorded in the dorsolateral prefrontal cortex (DLPFC) at a wide variety of cortical depths and found the following: DLPFC neurons—especially deep DLPFC—encode sensory evidence with information persisting into a working memory period. When targets are presented, DLPFC neurons encoded the target configuration at a short latency (∼100 ms). Finally, DLPFC neurons signaled action choice related signals with low latency (200 ms) once the stimulus-response association is revealed.

This low latency response to sensory evidence, potential actions, and action choice all suggest that DLFPC is a key cortical locus involved in perceptual decision-making.