SUBTHALAMIC NUCLEUS AND MORAL DECISION MAKING: A LOCAL FIELD POTENTIAL STUDY IN PATIENTS WITH PARKINSON’S DISEASE M. Fumagalli, M. Rosa, G. Giannicola, S. Marceglia, S. Mrakic-Sposta, C. Lucchiari, A. Albanese, L. Romito, A. Franzini, D. Servello, M. Porta, M. Sassi, C. Pacchetti, S. Barbieri, G. Pravettoni & A. Priori Università degli Studi di Milano; Fondazione I.R.C.C.S. Cà Granda Ospedale Maggiore Policlinico di Milano. Moral judgment refers to the concept of human action which pertains to matters of right and wrong. Advanced Parkinson’s disease (PD) is often associated to an alteration of decisional processes. The subthalamic nucleus (STN) is involved in executive functions and in decisional processes. Deep brain stimulation (DBS) besides an effective therapeutic tool, is a physiological “window” on human subcortical structures that through local field potentials (LFPs) recordings in patients, provided an amount of physiological data on basal ganglia, especially in relation to their motor, cognitive and affective functions. STN LFPs reflect synchronized pre-synaptic and post-synaptic activity of large populations of neurons. This study aims to investigate whether STN LFP activity is modulated by the emotional and cognitive processing of moral conflictual stimuli. To do so, we investigated the LFP activity in the STN of 14 PD patients with STN-DBS electrodes in response to neutral, moral conflictual and moral non-conflictual sentences. Subthalamic LFPs were recorded from the implanted electrodes during the execution of a moral task. The power spectrum analysis showed that, whatever the class of statements (neutral, moral conflictual, moral non-conflictual), the decisional phase was significantly higher than the basal condition specifically in the low-frequency (LF) band (5-13Hz). To detect the time course of LF oscillations, we performed time-frequency analysis. All averaged data for each class of statements trials showed significant power increase in the decisional phase compared to the baseline condition (p<0.0001). Both LF activity in moral non-conflictual and neutral sentences were significantly lower than the conflictual one (p<0.05). These results suggest that STN activity is specifically modulated by conflictual stimuli. We conclude that STN has a role in orienting decisions and behaviors. Hence neural encoding underlying moral decision making process spreads beyond the cerebral cortex, involving the basal ganglia with specific temporal dynamics.
Contatto e-mail: manuela.fumagalli@policlinico.mi.it