Autonomic Responses as a Window on Cognitive Control

Abstract

Cognitive control is a core construct in cognitive psychology and computational neuroscience, capturing an individual’s ability to over-ride automatic responses or processing of stimuli to improve goal-directed behavior. This ability underlies individuals’ broader self-regulatory capacity thought to mediate adaptive responses to environmental demands which help to maintain homeostasis. As such, a clearer understanding of the limits of control stands to improve diagnostic and interventional approaches to failures of adaptive responses – a core feature of many clinical-level impairments in psychology, psychiatry, and broader medical disciplines. One major barrier to the study of cognitive control is the quantification of control use at the individual level. In general, control use is defined in a circular manner where increased task difficulty is inferred from reduced performance and performance reductions are presumed to reflect increased difficulty and thus increased control demands. However, cognitive control is closely linked with the aversive experience of mental effort and mediated by motivational state. An improved method for quantifying the effortful use of control at the individual level may help disentangle the extent to which task difficulty (a function of trait processing ability) and control use (a function of state processing ability) are ultimately realized as individual differences in task performance in the laboratory or adaptive behavior in the real world. For a given level of motivation, increases in cognitive control use result in a subjective experience of effort and coincide with measurable changes in autonomic nervous system activity, opening the possibility of using changes in autonomic responses to quantify individual differences in cognitive control use. In this dissertation, I present three projects which center on autonomic responses measured at the cardiac and pupil level. I played a central role in the design, data collection, analysis, and write up of all three projects, reflecting in the associated first-author papers included in the appendices. Chapter 1 introduces the topic and provides a framework for understanding the associated context of three works. Chapter 2 summarizes a cardiac autonomic blockade study designed to improve the interpretation of changes in heart rate variability. Chapter 3 summarizes a cognitive pupillary response study which uses light to probe individual differences in autonomic control. Chapter 4 summarizes a behavioral and pupillary response study which manipulated task demands to attempt to measure individual differences in cognitive control use. Finally chapter 5 presents a conclusion for the dissertation as well as future directions.