The human subthalamic nucleus transiently inhibits active attentional processes

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neurosurgery

Background:

• The subthalamic nucleus (STN) is crucial for motor control and a target for Parkinson's disease treatment via deep brain stimulation (DBS).
• The STN's connections extend to cognitive circuits, suggesting a role beyond motor function, potentially in attention.
• STN-DBS can influence cognitive processes, hinting at the STN's involvement in non-motor inhibition.

Purpose of the Study:

• To investigate the human subthalamic nucleus's role in the momentary inhibition of visual attention.
• To determine if STN activity precedes and mediates the attentional decline caused by distracting stimuli.
• To causally test the STN's contribution to attention inhibition using DBS.

Main Methods:

• Recorded intracranial local field potentials (LFP) from STN DBS implants in an outpatient setting during a visual attention task.
• Simultaneously recorded high-density EEG to derive the steady-state visual evoked potential (SSVEP) as a neural index of visual attention.
• Modulated STN activity via DBS in a separate experimental session to assess causal effects on attention.

Main Results:

• Sound-related gamma-frequency activity in the STN preceded reductions in SSVEP following distracting sounds.
• Trial-to-trial modeling indicated that STN activity statistically mediated the suppressive effect of sounds on SSVEP.
• STN modulation via DBS significantly reduced the sound-related suppressions of SSVEP, providing causal evidence.

Conclusions:

• The human STN contributes to the inhibition of attention, supporting a domain-general inhibitory role.
• Findings suggest a mechanism for cognitive side effects of STN-DBS, particularly on attention.
• The novel outpatient LFP recording technique enables studying subcortical nuclei in cognitive tasks.