The tremor network targeted by successful VIM deep brain stimulation in humans

Area of Science:

• Neuroscience
• Neurosurgery
• Medical Imaging

Background:

• Deep brain stimulation (DBS) of the ventral intermediate nucleus of thalamus (VIM) treats intractable tremors like essential tremor and Parkinson disease (PD).
• Functional studies suggest VIM DBS modulates remote brain regions, but the underlying structural network remains unclear.

Purpose of the Study:

• To analyze the structural network responsible for clinical tremor modulation by VIM DBS.
• To identify the specific brain connections mediating the therapeutic effects of VIM stimulation.

Main Methods:

• Observational study involving 12 patients with tremor undergoing VIM DBS.
• Noninvasive diffusion tractography initiated from effective VIM electrode contacts.
• Comparison of connectivity from effective versus ineffective stimulation sites to assess the role of motor pathways.

Main Results:

• VIM DBS led to significant tremor reduction and improved quality of life.
• Tractography revealed a reproducible structural network connecting VIM to motor cortical, subcortical, cerebellar, and brainstem regions.
• Connectivity to the primary motor cortex appeared critical for successful tremor suppression.

Conclusions:

• VIM DBS modulates a complex structural network, providing the anatomical basis for its remote effects in tremor.
• This study utilized DBS to investigate human thalamic networks, a method typically limited to animal models.
• Preoperative tractography may enhance stereotactic planning for VIM DBS in tremor and other neurological disorders.