Andres Lozano: Parkinson's, depression and the switch that might turn them off

Summary

In this compelling presentation, a neurosurgeon explores the evolution of neurosurgery and the remarkable potential of deep brain stimulation (DBS). Using precise electrodes implanted in specific brain circuits, DBS can modulate neuronal activity to treat movement disorders like Parkinson’s and dystonia, mood disorders such as severe depression, and cognitive deficits in Alzheimer’s disease. The speaker highlights how targeted electrical stimulation can restore function, increase brain metabolism, and improve patients’ quality of life. With ongoing clinical trials and multidisciplinary collaboration, DBS represents a transformative approach, offering hope for repairing brain circuits and expanding the possibilities of treating neurological and psychiatric conditions.

Takeaways

• 🧠 Neurosurgery has a long history, dating back 7,000 years, with early practices like trepanation aimed at treating neurological and psychiatric disorders.
• 🔬 Different areas of the brain control specific functions such as movement, mood, memory, and appetite.
• ⚡ Dysfunctional neurons in specific circuits cause diseases like Parkinson’s, depression, dystonia, and Alzheimer’s.
• 🔌 Deep Brain Stimulation (DBS) involves implanting electrodes in targeted brain regions to modulate activity.
• 📡 DBS electrodes are connected to a pacemaker-like device under the skin, adjustable remotely like a TV remote.
• 👩‍⚕️ DBS has been successfully used to treat movement disorders, including Parkinson’s disease and childhood dystonia, restoring mobility and quality of life.
• 💔 DBS in the 'sadness center' (area 25) can reduce hyperactivity in patients with severe depression and reactivate frontal brain regions, improving motivation and mood.
• 🧩 DBS in the fornix can enhance glucose utilization in memory circuits, offering potential cognitive improvement for Alzheimer’s patients.
• 📊 Clinical trials are ongoing for DBS in depression (Phase III) and early Alzheimer’s disease to assess safety and efficacy.
• 🤝 The future of DBS involves interdisciplinary collaboration among engineers, scientists, neurologists, psychiatrists, and neurosurgeons to expand its applications.
• ⚡ DBS not only modifies symptoms but may also promote repair and enhanced function in damaged brain circuits.
• 🎯 Understanding and precisely targeting brain circuits allows neurosurgeons to treat previously untreatable neurological and psychiatric disorders.

Q & A

What is deep brain stimulation (DBS) and how does it work?

Deep brain stimulation (DBS) is a neurosurgical procedure in which electrodes are implanted in specific areas of the brain to modulate neural activity. It works like a 'radio dial,' allowing doctors to turn neural circuits up or down to restore function in movement, mood, or cognitive circuits.

What historical practice is mentioned as an early form of neurosurgery?

Trepanation, practiced in Mesoamerica around 7,000 years ago, involved making holes in the skull to release evil spirits thought to cause neurological or psychiatric disorders.

How are brain circuits related to different diseases?

Different brain circuits control specific functions. Malfunctioning circuits can lead to movement disorders (Parkinson’s), mood disorders (depression), or cognitive deficits (Alzheimer’s), depending on which neurons are misfiring or underactive.

How does DBS help patients with Parkinson's disease?

DBS targets misfiring neurons in motor circuits, such as the subthalamic nucleus, to suppress abnormal activity, reducing tremors and improving movement almost instantly.

Can you give an example of DBS helping a child with dystonia?

A nine-year-old boy with severe genetic dystonia, who could no longer walk or stand, received DBS in the same area used for Parkinson’s treatment. Three months after surgery, his movements were restored, and he is now living a normal life.

How is DBS being applied to treat depression?

DBS targets area 25 of the brain, the 'sadness center,' to reduce overactivity while restoring activity in underactive frontal lobe circuits. This has led to significant improvements in treatment-resistant depression.

What are the cognitive applications of DBS?

DBS is being tested in patients with early Alzheimer’s disease to stimulate memory circuits, such as the fornix. This restores glucose utilization in previously underactive areas and may improve cognitive function.

What evidence suggests DBS can restore brain function beyond symptom management?

Imaging studies show that after DBS, previously underactive areas in depressed or Alzheimer’s patients regain normal activity, suggesting that DBS may not only modify symptoms but potentially support reparative brain functions.

Why is DBS considered an interdisciplinary approach?

DBS involves neurosurgeons, neurologists, psychiatrists, engineers, imaging scientists, and basic scientists working together to map brain circuits, implant electrodes, and optimize stimulation for various diseases.

What is the future potential of DBS according to the speaker?

The speaker envisions DBS expanding to treat more neurological and psychiatric disorders, potentially assisting in brain repair, and continuing to refine the modulation of neural circuits to improve patient outcomes.

How is the effectiveness of DBS measured in patients?

Effectiveness is measured by observing improvements in symptoms, such as reduced tremors or restored movement, behavioral changes in depression, and increased glucose metabolism in memory circuits in Alzheimer's patients.

Why does the speaker compare DBS to adjusting a radio dial?

The analogy illustrates that DBS allows precise modulation of brain activity—turning circuits up or down as needed—just like tuning a radio to a desired station and adjusting the volume.