Motor thalamus plays a crucial role in integrating and modulating sensorimotor information. While voltage power spectral changes in 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 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 increase in broadband power were more spatially discrete, primarily involving the inferior recording sites within ventral thalamus. One subject also performed an imagined movement task during which low frequency oscillatory power was suppressed. These electrophysiologic changes may be leveraged as biomarkers for thalamic functional mapping, DBS targeting, and closed loop applications.
Keywords: Broadband; Deep Brain Stimulation; Field Potentials; Motor Thalamus; Movement Disorders.