Processing of emotional information in the human subthalamic nucleus

Area of Science:

• Neuroscience
• Neurology
• Psychiatry

Background:

• The subthalamic nucleus (STN) is a key target for deep brain stimulation (DBS) in Parkinson's disease and obsessive-compulsive disorder (OCD).
• STN high-frequency stimulation (HFS) can induce behavioral changes like impulsivity and hypomania.
• The role of the STN in processing emotional information remains incompletely understood.

Purpose of the Study:

• To investigate whether the STN processes emotional information.
• To determine if emotional processing in the STN is modulated by motor demands.
• To examine the influence of dopaminergic medication on STN emotional processing.

Main Methods:

• Local field potentials were recorded from the STN in 16 Parkinson's disease patients undergoing DBS.
• Patients performed an emotional categorization task with varying stimulus valence (pleasant, unpleasant, neutral) and response conditions (motor, non-motor, passive).
• Recordings were conducted both with and without dopaminergic medication.

Main Results:

• Emotional stimuli (pleasant, unpleasant, neutral) evoked event-related potentials (ERPs) in the STN.
• Without dopamine, ERPs were larger for unpleasant stimuli, particularly in the ventral STN, irrespective of the motor response.
• With dopamine, ERPs increased for pleasant stimuli, while responses to unpleasant stimuli remained unchanged.

Conclusions:

• The ventral STN processes emotional valence independently of motor context.
• Dopamine enhances the processing of pleasant emotional information within the STN.
• These findings support the STN's role in human emotional processing and may explain DBS-induced behavioral changes.