Mapping human thalamocortical connectivity with electrical stimulation and recording

The brain's functional architecture is shaped by electrophysiological interactions between its components, encompassing both cortical and subcortical structures. In this study, we provide an atlas of electrophysiological causal connections across 4,864 brain sites in 27 human participants using repeated single-pulse electrical stimulations and recordings with intracranial electrodes implanted in cortical regions and multiple thalamic nuclei. We show distinct spectral signatures elicited by perturbations of specific brain areas. Identified features of causal connectivity exhibited highly organized yet distinct patterns, indicating that each feature may correspond to a separate mode of information transmission across brain regions. Notably, we report a new waveform with unique temporal and spatial characteristics specifically linked to thalamic stimulations, namely delayed-onset theta oscillations in both ipsilateral and contralateral cortical regions. These findings contribute to a more detailed understanding of the human brain's functional architecture and offer valuable data for the development of biologically informed computational models.