PROJECT SUMMARY ABSTRACT The lateral cerebellum (Crus I/II) interacts with two dissociable large-scale brain networks — the executive control (ECN) and default mode networks (DMN), which support distinct cognitive functions (e.g., prediction versus episodic memory, respectively). The proposed research aims to identify noninvasive brain stimulation parameters that cause this area of the cerebellum to interact more heavily with either network, thereby biasing lateral cerebellar participation in network-specific cognitive functions critical to adult humans. Because the ECN and DMN have been shown to generate different endogenous rhythms of brain activity, the approach of the proposed project is to vary the rhythms at which repetitive transcranial magnetic stimulation (rTMS) is delivered. We hypothesize that matching rhythmic stimulation to network-specific endogenous activity will bias the lateral cerebellum to interact with the network having the corresponding intrinsic frequency. Resting-state fMRI and EEG will be used to assess network-level consequences of manipulating stimulation rhythm. We further aim to determine how stimulation-modulated brain activity influences network-related cognitive function. We hypothesize that changes in the ECN will correspond to changes in prediction-related behavior and brain activity, whereas changes in the DMN will correspond to changes in episodic memory behavior and brain activity. This research and training plan will thus merge noninvasive stimulation methods with resting-state and task-based fMRI and EEG measures of brain and cognitive function. The proposed studies will provide an experimental test of network-specific neuromodulation via a shared cerebellar hub, which could motivate procedures to enhance specific cognitive functions through noninvasive brain stimulation.

PROJECT NARRATIVE The lateral cerebellum can functionally interact with distinct large-scale brain networks, and the factors governing this selectivity are poorly understood. This project would test whether noninvasive stimulation of the cerebellum can influence its interaction with two networks, with the hypothesis that the frequency of noninvasive stimulation will generate network-specific effects. This project aims to determine whether stimulation can be optimized to selectively alter specific brain networks and associated cognitive functions, which could have the potential to inform treatment for network-specific dysfunction in psychiatric and neurological disorders.