Word onset tracking in neural responses of human basal ganglia nuclei

Abstract

Auditory speech is a highly relevant ecological stimulus with intrinsic temporal dynamics. At the cortical level, it is well established that neural responses contain information about the temporal dynamics of speech. Previous research further suggests that the basal ganglia also play a role in temporal processing. However, it is unknown whether neural responses in basal ganglia structures contain information about temporal speech structure. To address this question, we recorded local field potentials from the subthalamic nucleus (STN) and the globus pallidus internus (GPi) through contacts of deep brain stimulation (DBS) electrodes in patients with movement disorders (STN in Parkinson’s disease, GPi in Tourette syndrome or dystonia) while they listened to two-speaker speech streams with a task-relevant and an -irrelevant speech stream. Compared to baseline, amplitude modulations occurred in the beta-band (12–30 Hz) during listening to speech (word onset and duration) both in STN or GPi. Furthermore, the neural responses in both subcortical structures tracked word onsets during two-speech stream presentations, indicating that they code information about temporal speech structure. These findings provide further evidence that basal ganglia are involved in gating information about temporal speech structure relevant for task goal-directed processing.

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