The gene expression signature of electrical stimulation in the human brain
Direct electrical stimulation (eSTIM) is widely used clinically, from neurosurgical mapping to therapeutic interventions for neurological and neuropsychiatric disorders (1-10). Despite over a century of application, its molecular and cellular underpinnings remain unknown. Here, using state-of-the-art single-nuclei multiomic profiling, we map changes in cell-type-specific gene expression and chromatin accessibility in vivo in the human cortex following eSTIM of neurosurgery patients. eSTIM impacts a network of cells that extends beyond excitatory neurons to include inhibitory neurons, astrocytes, oligodendrocytes and microglia. We observed an upregulation of canonical immediate-early genes (IEGs: FOS, NPAS4, EGR4) in excitatory and inhibitory neurons and induction of cytokine-related genes CCL3 and CCL4 in microglia. The cross-species conservation of this gene signature, together with our examination of a cohort of both epilepsy and cancer patients, underscores the fundamental role of these changes in stimulation-driven plasticity while controlling for disease and environmental confounds. Our study of changes in chromatin accessibility reveals a common code that involves a cell-type specific signature of transcription factor binding motifs for members of the EGR family. By addressing these previously unexplored questions about activity-induced gene expression in vivo in the human brain, our findings challenge the long-standing neuron-centric view of eSTIM, highlighting the broader role of non-neuronal cells, including microglia, in mediating the impact of brain stimulation. Overall design: We performed bulk RNA-Seq on samples obtained from human subjects (n=4 pairs) and mouse cortex (n=4 pairs) before and after electrical stimulation. The human bulk RNA-seq was performed in two paradigms: stimulated (n=4 pairs) and unstimulated (n=4 pairs). Additionally, we performed sn-multi-omics sequencing on samples obtained from human subjects (n=6 pairs) before and after electrical stimulation.