Internal Capsule/Nucleus Accumbens Deep Brain Stimulation Increases Impulsive Decision Making in Obsessive-Compulsive...

Area of Science:

• Neuroscience
• Psychiatry
• Neurosurgery

Background:

• Deep brain stimulation (DBS) of the anterior limb of the internal capsule (ALIC)/nucleus accumbens effectively treats obsessive-compulsive disorder (OCD).
• However, ALIC/nucleus accumbens DBS may paradoxically increase impulsive behavior in patients.

Purpose of the Study:

• To investigate how active ALIC/nucleus accumbens DBS affects specific subdomains of impulsive decision-making in OCD patients.
• To determine if the location of stimulation sites influences the observed changes in impulsivity.

Main Methods:

• Fifteen OCD participants underwent the Cambridge Gambling Task during active and inactive ALIC/nucleus accumbens DBS.
• Stimulation-induced changes in risk adjustment and delay aversion were assessed.
• Probabilistic stimulation mapping and fiber filtering using structural connectivity data identified neural correlates of altered impulsivity.

Main Results:

• Active DBS significantly reduced risk adjustment and increased delay aversion, indicating heightened impulsive decision-making.
• Changes in risk adjustment correlated with stimulation in the central ALIC and specific thalamo-cortical and subthalamo-cortical fiber pathways.
• These associations with central ALIC stimulation and affected fibers were robustly validated.

Conclusions:

• ALIC/nucleus accumbens DBS demonstrably increases impulsive decision-making in OCD patients.
• The specific impact on risk adjustment is dependent on stimulation volume and affected neural pathways.
• Further research is needed to explore the link between DBS-induced impulsivity and long-term clinical outcomes in OCD.