Cerebral blood flow changes during vagus nerve stimulation for depression

Area of Science:

• Neuroscience
• Medical Imaging
• Psychiatry

Background:

• Treatment-resistant major depression (TRMD) poses a significant clinical challenge.
• Vagus nerve stimulation (VNS) is an emerging neuromodulation therapy for TRMD.
• Understanding the neurobiological effects of VNS is crucial for optimizing treatment.

Purpose of the Study:

• To investigate the acute effects of vagus nerve stimulation (VNS) on regional cerebral blood flow (rCBF) in TRMD patients.
• To identify specific brain regions affected by VNS using Positron Emission Tomography (PET).

Main Methods:

• Utilized Positron Emission Tomography (PET) with oxygen-15 labeled water ([15O]H2O) to measure rCBF.
• Administered VNS in an off-on sequence across four 90-second scans per subject.
• Employed image analysis techniques including alignment, global uptake normalization, and resampling to standard atlas space.

Main Results:

• VNS significantly increased rCBF in the bilateral orbitofrontal cortex, bilateral anterior cingulate cortex, and right superior/medial frontal cortex.
• VNS decreased rCBF in the bilateral temporal cortex and right parietal area.
• Observed changes correlated with brain structures implicated in depression and vagus nerve afferent pathways.

Conclusions:

• Acute VNS modulates rCBF in key brain regions relevant to major depression.
• These findings support VNS as a potential therapeutic strategy for TRMD by influencing neural activity in mood-related circuits.
• The study highlights the utility of PET imaging in elucidating the neurophysiological mechanisms of VNS.