Poster E135, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
Arousal-induced changes in functional brain networks during exploration and exploitation
Nathan Tardiff1, Danielle S. Bassett1, Sharon L. Thompson-Schill1; 1University of Pennsylvania
There is growing interest in how large-scale changes in functional brain networks support cognition. Neuromodulatory actions of norepinephrine (NE) may help facilitate these changes. To date, the relationship between NE and functional connectivity has not been assessed within the context of a task with an established relationship between NE-associated arousal and behavior. Here we probed the relationship between NE and network dynamics within an exploration/exploitation task that is known to induce changes in NE activity as measured by pupil diameter. Subjects underwent current fMRI and pupillometry while completing two high volatility and two low volatility blocks of a bandit task. Manipulating the rate of change of the value of the options in the task was intended to induce greater block-level variations in arousal. We parcellated the brain into 264 regions, estimated functional connectivity via wavelet coherence, and used a dynamic community detection algorithm over sliding time windows to track changes in network architecture over time. Within both block types, explore trials were associated with larger pupil diameter than exploit trials. Overall, subjects also explored more in high volatility blocks. Average baseline pupil diameter was also larger in high volatility blocks, though this difference did not reach significance in these preliminary data (N=9). In accordance with our predictions, block-wise changes in average baseline pupil diameter were negatively associated with average integration between functional networks. These data provide preliminary evidence that while task-focused states are facilitated by increased functional integration, exploratory states may be facilitated by less integration between functional networks.
Topic Area: THINKING: Decision making