Date: Wednesday, December 11, 2024
Location: 46-3002 (Singleton Auditorium)

Speaker: Katalin M. Gothard, M.D., Ph.D.
Affiliation: Professor of Physiology, College of Medicine, The University of Arizona

Host: Dr. Mehrdad Jazayeri

Talk title: Interoceptive signals bias perception and decision making 

Abstract: Grooming by a trusted social partner represents the macaque equivalent of affective touch in humans. In both species, affective touch induces vagal tone, a hallmark of positive affect. In this socio-emotional context, instead of responding to each sweep, neurons in the amygdala respond to a bout of grooming with small but sustained alterations in baseline firing rates. We hypothesize that these small but consistent baseline changes are driven by interoceptive afferents signaling the body’s physiological state to the brain as part of the coordinated brain-body state of positive affect. To test this hypothesis, we manipulated the physiological state of the body using drugs with minimal or no direct effect on the brain and measured the resulting changes in the spontaneous activity of neurons in the brain. We observed a clear correlation between heart rate and baseline neuronal firing rates in the amygdala and somatosensory areas, suggesting that the spontaneous neural activity closely tracks fluctuations in internal physiological states. To determine the putative cognitive and behavioral consequence of different body states we measured the changes in decision making induced by the drugs that altered baseline firing rates. Monkeys performed an approach-avoidance conflict task, where they had the option to either endure a mildly aversive (but not painful) stimulus in exchange for juice reward or to end the trial by terminating both the aversive stimulus and the reward. Drug-induced sympathetic-dominated states reduced the monkeys’ tolerance for aversive stimuli, indicating a causal relationship between physiological states and decision-making. Ongoing studies explore where and how interoceptive afferents bias decision making in the brain.