Neurosurgery scope and subspecialization
Halpern explains what neurosurgeons treat across brain, spine, and peripheral nerves. He describes modern subspecialization and his focus in stereotactic functional neurosurgery.
Essentials: Compulsive Behaviors & Deep Brain Stimulation | Dr. Casey Halpern
Source description
In this Huberman Lab Essentials episode, my guest is Dr. Casey Halpern, MD, a professor of neurosurgery at the Perelman School of Medicine at the University of Pennsylvania. We discuss how deep brain stimulation and other neuromodulation approaches are being used to treat …
In this Huberman Lab Essentials episode, my guest is Dr. Casey Halpern, MD, a professor of neurosurgery at the Perelman School of Medicine at the University of Pennsylvania. We discuss how deep brain stimulation and other neuromodulation approaches are being used to treat Parkinson's disease, obsessive-compulsive disorder (OCD), binge eating disorder and depression-related symptoms. We also explore the brain circuits that drive compulsions, cravings and impulsivity, as well as emerging non-invasive tools for predicting and treating harmful behaviors. Read the episode show notes at hubermanlab.com. Thank you to our sponsors AG1: https://drinkag1.com/huberman Function: https://functionhealth.com/huberman Rorra: https://rorra.com.huberman
Key Topics
- Neurosurgery scope and subspecialization
- Deep brain stimulation basics
- Side effects as circuit clues
- Psychiatric improvements during movement DBS
- OCD as a spectrum and when it becomes a disorder
- First-line OCD treatments and limits
- Treatment-refractory OCD and surgical options
- DBS versus capsulotomy ablation tradeoffs
- Typical response rates and unmet need
- OCD circuit framing: cortex to basal ganglia
- Ventral striatum and nucleus accumbens in compulsions
- “Urge despite risk” as a shared mechanism
- Nucleus accumbens functions in health and pathology
- Finding symptom-specific signals during surgery
- Why “craving” is a practical clinical construct
- Proof-of-concept obsession cells in OCD
- Non-invasive brain stimulation: promise and imprecision
- TMS current clinical role and as a circuit probe
- Focused ultrasound today and future directions
- Limits of ultrasound for psychiatric disease
- Stereo-EEG as a model for psychiatric circuit mapping
- Toward invasive-to-noninvasive translation
- Why obesity and binge eating may be more tractable initially
- Awareness as a tool and where it fails
- Closed-loop detection of craving-related signals
- Laboratory mood provocation to elicit binges
- Why CBT can require ongoing reinforcement
- AI and wearables for early warning of episodes
- Compulsion versus impulsivity distinctions
- Scalability and the role of neurosurgery in public health
Deep brain stimulation basics
DBS involves implanting thin insulated leads into specific brain targets. Therapy comes from delivering adjustable electrical stimulation through tiny contacts to modulate local circuits.
Side effects as circuit clues
Stimulating nearby regions can briefly trigger laughter, panic, or other emotional states. Those transient effects can reveal therapeutic targets for mood and compulsive symptoms.
Psychiatric improvements during movement DBS
Some Parkinson’s patients report reduced gambling, improved mood, or less compulsivity after DBS for tremor. This suggests motor targets can intersect with limbic and reward circuitry.
OCD as a spectrum and when it becomes a disorder
He frames obsessionality and compulsivity as traits that can be adaptive when controlled. OCD is when obsessions and compulsions become intrusive, uncontrollable, and impairing.
First-line OCD treatments and limits
SSRIs and certain tricyclics are common medication approaches targeting serotonin-related systems. Exposure and response prevention is highlighted as highly effective but not sufficient for all patients.
Treatment-refractory OCD and surgical options
A subset of patients remains severely symptomatic despite meds and therapy. For them, DBS or lesion procedures like capsulotomy may be considered with careful risk-benefit counseling.
DBS versus capsulotomy ablation tradeoffs
DBS is adjustable and reversible in effect, while ablation destroys a small brain region. He notes ablations can help with few obvious side effects but remain irreversible surgery.
Typical response rates and unmet need
He cites responder rates around 50% for current surgical approaches, with many responders still symptomatic. This motivates more symptom-specific targeting and personalized circuit approaches.
OCD circuit framing: cortex to basal ganglia
He describes hyperfunctioning prefrontal and orbitofrontal cortex with projections into basal ganglia circuits. The ventral striatum becomes a key node for compulsive behavior gating.
Ventral striatum and nucleus accumbens in compulsions
The ventral striatum, including nucleus accumbens, is discussed as central to reward seeking and compulsion. Disruption can shift behavior toward pursuing reward despite punishment.
“Urge despite risk” as a shared mechanism
He links OCD, addiction, and some eating disorders through persistent urges that override judgment and safety. This common denominator guides target selection and translational research.
Nucleus accumbens functions in health and pathology
Nucleus accumbens is positioned as an integrative reward circuit hub. Pathology arises when strong repeated rewards or stressors hijack normal control and amplify maladaptive urges.
Finding symptom-specific signals during surgery
In Parkinson’s, surgeons can detect tremor-related neural patterns to guide placement. Halpern aims to find analogous “craving” or “obsession” signals to improve psychiatric targeting.
Why “craving” is a practical clinical construct
He prefers the term craving because patients recognize and report it reliably. It can be more accessible than labels like loss of control or binge behavior for some individuals.
Proof-of-concept obsession cells in OCD
He describes a single-case effort to identify neural activity linked to obsessions intraoperatively. The goal is to optimize electrode placement by anchoring to disease-relevant physiology.
Non-invasive brain stimulation: promise and imprecision
Halpern argues non-invasive approaches should be embraced but made more precise. He notes mechanisms are often unclear, similar to ongoing uncertainty about DBS mechanisms.
TMS current clinical role and as a circuit probe
He notes TMS is FDA-approved for depression, OCD, and nicotine addiction. TMS may help define circuits and identify candidates who could benefit from invasive trials if effects are temporary.
Focused ultrasound today and future directions
MRI-guided focused ultrasound is described as an FDA-approved non-invasive ablation for tremor. Research is exploring modulation without lesioning and opening the blood-brain barrier for targeted delivery.
Limits of ultrasound for psychiatric disease
He emphasizes the main barrier is not the tool but target uncertainty. Without knowing the right circuit node, psychiatric ultrasound ablation may only replicate older targets and outcomes.
Stereo-EEG as a model for psychiatric circuit mapping
He describes modern stereoencephalography in epilepsy as safe and informative for locating seizure networks. Similar invasive recordings could map psychiatric circuits and improve targeting strategies.
Toward invasive-to-noninvasive translation
He outlines a pathway where invasive recordings define reliable targets first. Those pooled data could later support non-invasive targets for ultrasound or other modalities.
Why obesity and binge eating may be more tractable initially
He suggests preclinical models can capture aspects of binge and obesity better than some psychiatric syndromes. This supports earlier target development for DBS in those conditions compared to others.
Awareness as a tool and where it fails
Both discuss whether better interoception and state awareness can prevent episodes. Halpern notes the most severe patients can be highly aware yet still lose control, implying a deeper circuit failure.
Closed-loop detection of craving-related signals
He describes implanted devices that record population activity to detect states linked to cravings. The aim is to trigger stimulation at home when patterns indicate elevated risk of binge behavior.
Laboratory mood provocation to elicit binges
A validated mood provocation protocol is used to induce patient-specific emotional states tied to binge episodes. Brain signals are synchronized with video and eye tracking to capture pre-bite dynamics.
Why CBT can require ongoing reinforcement
He praises cognitive behavioral approaches while noting relapse can occur when therapy stops. Some patients need sustained intervention to maintain behavior change.
AI and wearables for early warning of episodes
They discuss machine learning using voice, physiology, sleep, and breathing to predict depressive or impulsive episodes before conscious awareness. Halpern argues invasive understanding will sharpen what to look for non-invasively.
Compulsion versus impulsivity distinctions
Halpern differentiates compulsion as persistent urge despite risk from impulsivity as failure to wait or inhibit action. He connects both to public health concerns like suicidality and addiction.
Scalability and the role of neurosurgery in public health
He acknowledges surgery cannot scale to tens of millions affected by obesity, depression, and addiction. He positions neurosurgical research as a way to rigorously define mechanisms and inspire scalable therapies.