CRCNS: Stochastic Models of Executive Control in Monkeys and Humans

Vanderbilt University, Nashville TN

Investigators

Abstract

Stochastic Models of Executive Control in Monkeys and Humans Abstract With National Science Foundation support, Drs. Logan, Palmeri, and Schall will conduct a three-year investigation of the executive control processes that underlie flexible responding in monkeys and humans. It is the hallmark of primate intelligence to be able to respond flexibly, focusing on different aspects of the same situation to produce arbitrary responses that are appropriate to current goals. The goal of this project is to specify executive processes computationally and neurally, focusing on the control of attention, categorization, and response preparation. To accomplish this goal, monkeys and humans will perform tasks that require them to make saccadic eye movements toward or away from targets that appear in displays of distractors. Experimental variables will be manipulated to selectively influence attention to the targets, categorization of targets and distractors, and preparation of eye movement responses. The timing and accuracy of eye movements will be recorded in both humans and monkeys performing the task, and the activity of ensembles of neurons in the frontal lobes of monkeys will be recorded while they are performing the task. The overt eye movement behavior of humans and monkeys and the neural activity of monkeys will be described in terms of a mathematically precise computational theory with three distinct components, as follows. (1) An attention component that selects behaviorally-relevant targets from a field of distractors; (2) a categorization component that selects goal-relevant interpretations of target stimuli; and (3) a response preparation component that selects responses necessary to accomplish the goals. The theory provides a common language that makes it possible to relate the overt behavior of humans to the overt behavior of monkeys and to relate the overt behavior of monkeys to the neural activity that underlies it. The research is significant in three respects. First, it will advance understanding of executive control processes by specifying them concretely in terms of computational and neural processes. Executive control processes are critical in a variety of contexts in the workplace, educational settings, and mental health settings that require people to deal with competing goals and switch between various activities, including the workplace, education, and mental health. The research will have implications for human factors, ergonomics, design of training programs in education and industry, and diagnosis and treatment of mental disorders. Second, the research will advance understanding of neural processes by providing linking propositions that relate single-cell behavior to psychological states of the cognitive processes that the single cells implement. Single-cell behavior makes sense only in the context of the behavior it underlies, and the research will provide that relation. Third, the research will advance understanding of the computations that underlie cognitive processes of attention, categorization, and response preparation. Computational models of these processes are limited by an inability to "open the black box" and observe the inner brain processes that underlie them. Computational models with very different internal processes often predict the same overt behavior. The research will identify cognitive processes with neural behavior, allowing distinctions between these computational models of human and monkey cognition.