High Beta Power in the Ventrolateral Prefrontal Cortex Indexes Human Approach Behavior: A Case Study.

Area of Science:

• Neuroscience
• Psychiatry
• Neuromodulation

Background:

• Deep brain stimulation (DBS) of the ventral capsule and ventral striatum (VC/VS) effectively treats resistant obsessive-compulsive disorder (trOCD).
• DBS initiation can acutely improve mood and energy, leading to increased social engagement and talkativeness, termed 'approach behaviors'.

Purpose of the Study:

• To investigate the neurophysiological basis of approach behaviors during VC/VS DBS.
• To explore the relationship between stimulation amplitude, ventrolateral prefrontal cortex (vlPFC) spectral power, and speech rate in a patient with trOCD.

Main Methods:

• Chronic intracranial recordings from vlPFC and orbitofrontal cortex (OFC) in one male patient with trOCD undergoing VC/VS DBS.
• Experiments comparing neurophysiological data and speech rate during high vs. low amplitude stimulation epochs over 17 weeks.
• Analysis of spectral power in the high beta frequency band (31±1.5Hz) and speech rate, with a specific test for speech's influence on neural activity.

Main Results:

• Speech rate and vlPFC high beta power increased significantly during high amplitude stimulation compared to low amplitude periods.
• A positive correlation was observed between speech rate and vlPFC high beta power, particularly in the left hemisphere.
• Speech itself, without stimulation changes, did not elevate vlPFC high beta power, indicating stimulation as the primary driver.

Conclusions:

• Ventrolateral prefrontal cortex (vlPFC) high beta power serves as a potential biomarker for approach behaviors induced by VC/VS DBS.
• This neural signal may represent a continuum from adaptive approach behaviors to maladaptive manic symptoms, warranting further investigation.