July 4, 2026

@michaelokun

Focused ultrasound and pallidotomy: what can lesions teach us that DBS cannot? A lesion means creating a permanent interruption in a brain circuit. Deep brain stimulation (DBS) uses electricity to modulate and reshape abnormal circuits without destroying tissue and importantly it can be adjusted, optimized and reversed if needed. Adam Zaidel and colleagues described in a fascinating paper (2008) in the European Journal of Neuroscience how prior pallidotomy lesions altered the physiology of the subthalamic nucleus (STN) years later in folks living w/ Parkinson's disease. As focused ultrasound lesioning rapidly expands across the globe, this older work may provide important clues into how lesion therapies and DBS differ in their effects on brain circuits. Thanks to my friend Hagai for reminding me about this one. Key points: - Prior pallidotomy reduced abnormal activity and oscillations in the STN, suggesting that lesioning one node in a network can reshape activity in distant connected regions. - The effects were durable and measurable years later, supporting the idea that lesion therapies may permanently reset portions of dysfunctional brain circuitry. - Despite these changes, STN DBS remained effective in many individuals, highlighting that lesioning and stimulation may improve symptoms through overlapping but distinct mechanisms. My take: The recent enthusiasm surrounding focused ultrasound is exciting and appropriate. For carefully selected folks, lesion therapies can be transformative. However, focused ultrasound and DBS are fundamentally different interventions and should not be viewed as interchangeable. DBS is more like installing a dimmer switch in a room. You can turn it up, turn it down, move the settings around and adapt as the disease evolves. Focused ultrasound is more like removing a wire from the circuit entirely. Sometimes that may be exactly the right strategy, however, once the wire is cut there is no putting it back. #tremor #parkinson