Poster session 3, Abstracts 816-949

Abstract

Objective: To evaluate the role of the subthalamic nucleus (STN) inlanguage processing in patients with Parkinson’s disease (PD). Microelectroderecordings obtained prior to the insertion of deep brain stimulation(DBS) electrodes, will be analysed to investigate the STN’s role in languageprocessing. More specifically, the aim of the present study is toinvestigate the difference between the dominant and nondominant STN insemantic processing and the role of the STN in the processing of wordswith negative emotional valence.Background: Recent studies have implicated the STN in language processing,as measured through functional changes in verbal fluency, discourse,lexical decision and high-level language, after patients with PDhave received DBS of the STN. The surgical procedure of DBS with theuse of microelectrode recordings for identification of the STN in surgery,allows for the unique opportunity to investigate the neuronal activity of thedorsolateral STN while patients are performing language tasks, and thereforefurther define the role of the STN in language processing.Methods: Two language tasks were performed intraoperatively by aseries of patients with PD, prior to the implantation of DBS electrodes. Thefirst task involved the auditory presentation of two words, either belongingto the semantic category of animals or household items. The participantswere required to manually respond as to whether the two words belongedto the same semantic category (e.g., cat–dog or door– chair) or differentsemantic categories (e.g., cat– chair). The second language task requiredthe participants to listen to a series of words that carried negative emotionalvalence (e.g., poverty or cancer) or were neutral in emotional valence (e.g.,clock or hat). Participants were again required to respond by manuallydepressing a response button to indicate negative or neutral. Microelectroderecordings were obtained from both the left and right STN during thecompletion of these tasks.Results: Preliminary findings from a series of patients will be presentedand discussed in relation to changes in neuronal activity as a function ofleft or right STN and task condition. In addition, behavioural data, such asreaction time and error rate analyses will also be presented.Conclusion: The use of microelectrode recordings prior to the implantationof electrodes for DBS provides not only a useful technique in thesurgical guidance of subcortical regions, but also allows the opportunity toinvestigate the role of these structures in language processing.