Electrophysiological registration of phonological perception in the subthalamic nucleus of patients with Parkinson's...

Phonological processing is usually associated with the activation of cortical areas, especially in the left cerebral hemisphere. This study examined if phonologically elicited evoked potentials can be recorded directly from the subthalamic nucleus in patients with Parkinson's Disease (PD). Seven PD patients who had undergone implantation of deep brain electrodes for the stimulation of the subthalamic nucleus were included. Local field potentials were recorded in a pre-attentive auditory phonological task, an attentive auditory phonological discrimination task, and a word recognition task. Auditory evoked potentials related to phonological, but not lexical processing, could be demonstrated in the subthalamic nucleus for all three tasks. Only minor changes were found after levodopa administration. This study demonstrates that the subthalamic nucleus is involved in early phonological perception, which puts the subthalamic nucleus in a position to modify phonological perception in a larger cortico-subcortical network.