Intrinsic brain network dynamics modulated by neural stimulation to cerebellum

Abstract

The cerebellum, with its distinctive architecture and extensive cortical connections, has long been recognized for its highly structured interconnectivity with the cortex and is newly proposed as part of a larger circuit that shapes brain network dynamics (McAfee et al., 2022; Shine, 2021). Here, we evaluate dynamic network reconfigurations in resting state fMRI connectivity pre- and post- noninvasive inhibitory repetitive transcranial magnetic stimulation (rTMS) targeting the right Crus I of the cerebellum. Using dynamic community detection to evaluate the stimulation’s effect on modular network structures, we characterize the network properties by which cerebellar stimulation spreads through the cortex. We find that: (1) the flexibility, or the likelihood of network nodes to change module allegiances, increased post stimulation; (2) the dynamic patterns by which module allegiances emerged and evolved were highly individual and did not follow a single functional prototype; and (3) the cerebellar nodes had connectivity properties of integrators for distinct network modules. These results are consistent with the idea that cerebellum is pivotal in modulating distributed cortical activity by restructuring the integration and segregation of neural networks. This integrative capacity of the cerebellum may underlie its proposed role in coordinating neural systems, including those supporting higher cognitive function.The cerebellum, with its distinctive structure and widespread cortical connections, plays a central role in cortical network dynamics that support higher cognition. Here, using resting-state fMRI connectivity, we evaluate how inhibitory repetitive transcranial magnetic stimulation to the right Crus I of the cerebellum alters dynamic network reconfigurations across the cortex. Dynamic community detection revealed three main effects: (1) network flexibility, the tendency of nodes to switch module affiliations, increased after stimulation; (2) the temporal evolution of module allegiances varied strongly across individuals, lacking a common functional prototype; and (3) cerebellar nodes acted as integrators linking distinct network modules. These results highlight the cerebellum’s pivotal role in reshaping cortical integration and segregation, supporting its proposed function in coordinating distributed neural systems underlying cognition and adaptive behavior.