Intracranial brain stimulation modulates fMRI-based network switching

https://doi.org/10.1016/j.nbd.2021.105401Get rights and content
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Highlights

  • rsfMRI network switching is attenuated during intracranial brain stimulation.

  • Stimulation-induced switching is observed distant from sites of electrical stimulation.

  • Our results are validated across a range of network parameters.

  • Network models may inform clinical efficacy of brain stimulation.

Abstract

The extent to which functional MRI (fMRI) reflects direct neuronal changes remains unknown. Using 160 simultaneous electrical stimulation (es-fMRI) and intracranial brain stimulation recordings acquired in 26 individuals with epilepsy (with varying electrode locations), we tested whether brain networks dynamically change during intracranial brain stimulation, aiming to establish whether switching between brain networks is reduced after intracranial brain stimulation. As the brain spontaneously switches between a repertoire of intrinsic functional network configurations and the rate of switching is likely increased in epilepsy, we hypothesised that intracranial stimulation would reduce the brain's switching rate, thus potentially normalising aberrant brain network dynamics. To test this hypothesis, we quantified the rate that brain regions changed networks over time in response to brain stimulation, using network switching applied to multilayer modularity analysis of time-resolved es-fMRI connectivity. Network switching and synchrony was decreased after the first brain stimulation, followed by a more consistent pattern of network switching over time. This change was commonly observed in cortical networks and adjacent to the electrode targets. Our results suggest that neuronal perturbation is likely to modulate large-scale brain networks, and multilayer network modelling may be used to inform the clinical efficacy of brain stimulation in epilepsy.

Keywords

Multilayer networks
fMRI
Network switching
Intracranial brain stimulation
Epilepsy

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