Human subthalamic neurons track speech features and couple with auditory cortex during preparatory listening

Abstract The basal ganglia–thalamocortical loop is widely implicated in speech production, yet its role during listening remains underexplored. Here, we show that human subthalamic nucleus (STN) single‑unit activity is modulated during auditory presentation of syllable triplets, and that a subset of neurons encodes phonetic (consonant and vowel) and sequence features prior to speech onset. Using intraoperative microelectrode recordings during deep brain stimulation implantation, ~39% of units showed significant firing‑rate modulation during the auditory epoch. Within these, we discovered “auditory‑syllable” units that carried phonetic and/or sequence information. Auditory presentation also elicited beta‑band desynchronization in STN LFPs and revealed frequency‑specific spike‑phase coupling (SPC) with cortex: auditory‑specific units coupled predominantly with superior temporal gyrus (STG) in alpha, whereas units modulated during both auditory and speech epochs preferentially coupled with sensorimotor regions in beta. Responses were observed to incidental, non‑task sounds in a subset of auditory‑specific units that support genuine auditory sensitivity. Together, these results support a role for the STN in auditory–motor integration and indicate frequency‑specific routing within human cortical–subcortical loops during listening.