Collaborative Research: CRCNS Research Proposal: Uncovering the mechanisms and meaning of brain rhythm frequency shifts during decision making

Categorization is a fundamental, but complex, cognitive ability. Depending on the context, the same feature could place an object or event in different categories. For example, categorizing animals as “big” vs. “small” varies when a house cat is considered “big” when compared to an ant and an elephant is considered “small” compared to whale. How brains handle these categorization decisions flexibly and adaptively remains elusive. This project investigates the role of brain waves in the prefrontal cortex in categorization task. The project studies brain activity in humans and animals while performing a decision-making task to leverage a computational model to better understand the brain mechanisms involved. This project has potential to open a new window into understanding of decision making and will set the stage for future investigations into disorders, such as Parkinson’s disease and schizophrenia, in which both brain waves and cognitive function are impaired. This project tests the novel hypothesis that beta oscillations at different frequencies could act as separate channels to selectively transmit decision information downstream, akin to frequency-division multiplexing. Specifically, beta frequency shifts in dorsolateral prefrontal cortex appear to synchronize different neuronal ensembles that represent specific decision outcomes. This research involves a close collaboration between computational and experimental neuroscientists, utilizing a neural modeling framework uniquely designed to link macroscale oscillatory activity to the underlying cellular- and circuit-level dynamics that can be assessed electrophysiologically. The modeling work will be informed by spectrotemporal analysis of previously collected human and rodent data, as well as new electrophysiological recordings and optogenetic neuromodulation experiments in rodents to test hypotheses on cell- and circuit-level generation of beta frequency shifts and their causal implications in the context of decision making. This approach, combining electrophysiological recordings, causal manipulation and modeling, is designed to answer core questions regarding a crucial brain mechanism underlying decision making, and will provide a grounded understanding of consistency in brain dynamics across species and tasks, and their implications for behavior. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.