Intracranial electrical stimulation alters meso-scale network integration as a function of network topology

Abstract

Human brain dynamics are organized into a multi-scale network structure that contains multiple tight-knit, meso-scale communities. Recent work has demonstrated that many psychological capacities, as well as impairments in cognitive function secondary to damage, can be mapped onto organizing principles at this mesoscopic scale. However, we still don’t know the rules that govern the dynamic interactions between regions that are constrained by the topology of the broader network. In this preregistered study, we utilized a unique human dataset in which whole brain BOLD-fMRI activity was recorded simultaneously with intracranial electrical stimulation, to characterize the effects of direct neural stimulation on the dynamic reconfiguration of the broader network. Direct neural stimulation increased the extent to which the stimulation site’s own mesoscale community integrated with the rest of the brain. Further, we found that these network changes depended on the topological role of the stimulation site itself: stimulating regions with high participation coefficients led to global integration, whereas stimulating sites with low participation coefficients integrated that regions’ own community with the rest of the brain. These findings provide direct causal evidence for how network topology shapes and constrains inter-regional coordination, and suggest applications for targeted therapeutic interventions in patients with deep-brain stimulation.

Intracranial brain stimulation modulates fMRI-based network switching

“…For each es-fMRI scan, this results in a 3D tensor of size 196 x 196 x 160 that represents the interconnectivity between each of the 196 brain regions, for 160 es-fMRI time-points (80 Stim time-points and 80 NoStim time-points, partitioned into alternating epochs -see Figure 2). In line with Thompson et al (2021), we excluded the first three time-points from each epoch to avoid overlap between Stim and NoStim, resulting in a total of 112 es-fMRI time-points for analysis.…”