Locus coeruleus-related insula activation supports implicit learning
Martin J. Dahl, Max Planck Institute for Human Development, Germany; Tiantian Li, Max Planck School of Cognition, Germany; Matthew R. Nassar, Brown University, United States; Mara Mather, University of Southern California, United States; Markus Werkle-Bergner, Max Planck Institute for Human Development, Germany
Session:
Posters 1A Poster
Presentation Time:
Thu, 24 Aug, 17:00 - 19:00 United Kingdom Time
Abstract:
Novel proxies for the noradrenergic locus coeruleus (LC) promise insights into a neuromodulatory system that has long been inaccessible in humans. We recorded pupil dilation, a readout of neuromodulatory activity, and fMRI during an oddball task (n = 77) to examine how noradrenergic neuromodulation relates to learning and decision-making. Proxies for structural LC integrity in the same participants were assessed using LC-sensitive MRI. We found that oddball trials elicited pupil dilation and salience network activation. Moreover, stronger salience network activation was coupled with larger pupil dilation and also with higher LC activity, suggesting that noradrenergic activity modulates the salience network. By relating behavior to proxies for the noradrenergic system, we found that participants implicitly learned the statistical structure of the task environment. LC-informed hierarchical Drift Diffusion Modeling (DDM) further revealed that participants developed a response accuracy bias for the more prevalent stimulus category. Moreover, individual differences in LC-related measures (pupil-indexed neuromodulation, salience network activation, structural LC integrity) were associated with implicit learning. Taken together, our data suggest LC activity promotes adapting behaviors to a new environment.