Spectral changes in motor thalamus field potentials during movement

The motor thalamus plays a crucial role in integrating and modulating sensorimotor information. Although voltage power spectral changes in the motor cortex with movement are well-characterized, corresponding activity in the motor thalamus, particularly broadband power change, remains unclear. The present study aims to characterize spectral changes in the motor thalamus during hand movements of 15 subjects undergoing awake deep brain stimulation surgery targeting the ventral intermediate (Vim) nucleus of the thalamus for disabling tremor. We analyzed power changes in subject-specific low-frequency oscillations (<30 Hz) and broadband power (captured in 65-115 Hz band) of serial field potential recordings. Consistent with previous studies, we found widespread decreases in low-frequency oscillations with movement. Importantly, in most subjects, we observed that sites with significant increases in broadband power were more spatially discrete, primarily involving the inferior recording sites within the ventral thalamus. One subject also performed an imagined movement task during which low-frequency oscillatory power was suppressed. These electrophysiological changes may be leveraged as biomarkers for thalamic functional mapping, DBS targeting, and closed-loop applications.NEW & NOTEWORTHY We studied movement-associated spectral changes in human motor thalamus and observed focal increases in broadband power with movement. This biomarker may be used as a tool for intraoperative functional mapping, DBS targeting, and closed-loop device control.