Rewiring the Self: Deep Brain Stimulation and the Search for Identity 

Adaptive Deep Brain Stimulation has been a medical miracle for me. But it came with a massive caveat: episodes of mania. I’ve fallen asleep on the streets of New Orleans after smoking god-knows-what with a stranger I had just met at a bar. I’ve gotten kicked out of a Montreal hospital after waking up there with a blinding hangover, angrily badgering nurses and shouting the names of local hospital executives I had just recently met. And then there was Cartagena, Colombia, where I passed out for 36 hours in my hotel room after being drugged and robbed, awakening to a surreal scene: a nurse administering an IV, a security guard showing me footage of myself being wheelchaired in, and a priest praying over me. Looking back, I have to ask: Who was that person?

For those of us navigating the relentless daily realities of Parkinson’s disease, DBS is the holy grail of symptomatic treatment. A neurosurgeon implants electrodes in your brain, then a neurologist flips a switch, and the tremors, rigidity, and dyskinesia melt away. However, a parallel narrative exists alongside these miracle stories: the patients who, once their motor symptoms have been programmed away, no longer feel like themselves.

This at times forces an impossible ethical tradeoff. If a patient is physically thriving but acting like a complete stranger, do you dial it back? Would you accept the return of Parkinson’s symptoms to get your spouse or yourself—back?

To understand this phenomenon, we must look beyond clinical trial data, which often labels severe psychiatric events simply as “rare”. During a recent appointment with my neuropsychiatrist, we discussed this exact ethical dilemma. He happens to be a co-author of a brilliant 2011 paper titled Deep Brain Stimulation and the Search for Identity, which not only became my inspiration for writing this piece but it also poses a question that the medical field remains unable to properly answer: What is the cost of a cure?

To measure this, the paper’s authors proposed the “foundational-function model,” suggesting that human identity operates much like a Jenga tower. Our “peripheral attitudes”—passing moods, preferences, and hobbies—are blocks near the top. If stimulation alters these, you are still essentially you. But our “core attitudes” are the foundation: deep-seated moral baselines and fundamental values.

After I woke up in that Colombian hotel, I was forced to confront my own Jenga tower. Was that episode just a peripheral shift, or had an electrode inadvertently knocked out a foundational block of my empathy and restraint? For a time, the original architecture of my identity had collapsed. In a very real sense, I had become someone else.

The reason this happens is an often unavoidable biological reality known as the “spillover effect”. The basal ganglia contain tightly packed, interconnected loops governing motor function, emotions, and cognition. When you stimulate the subthalamic nucleus to fix a tremor, the current inevitably bleeds into emotional and decision-making centers. You cannot treat the brain like a simple machine where one wire controls one distinct function.

Yet, when it comes to measuring the human mind, modern medicine is flying blind. Standard cognitive tests and depression scales are inadequate for detecting identity shifts. Patients can ace a memory test or score perfectly on a mood questionnaire, while their spouse sits in the waiting room feeling married to a ghost. Historically, it took the patient community—raising red flags in chatrooms and support groups—to force the scientific establishment to acknowledge what their clinical rulers were missing. 

As we look toward the rapid acceleration of brain-computer interfaces—from the refinement of next-generation adaptive DBS to the headlines generated by Neuralink—the warnings issued in the paper cited above over a decade and a half ago are more urgent than ever. We have entered an era where technology can actively rewrite not just our neural pathways, but our very selves.

In my case, I was fortunate. My core identity returned gradually over time. My neuropsychiatrist—drawing on the very research he helped author—understood the volatile ‘break-in’ period of neurostimulation. He knew that we needed to be patient as my brain adjusted. Slowly, the person who raged at nurses in Montreal faded away. The missing foundational blocks of my Jenga tower slid back into place before whoever that was did any permanent damage to me. But I’ve also come to know that not every patient is so lucky. 

For the Parkinson’s community, DBS remains an incredible, life-altering tool when applied to the right patient by the right team. I am among those whose lives have been saved by it. But as technology advances, neuroscience can no longer ignore how our brains and bodies build a sense of personal identity. We cannot treat the brain as just a complex motor, tweaking the dials until the gears run smoothly, without pausing to check on, for lack of a more scientific terminology, the ghost in the machine. A cured tremor means little if the cost is the patient is left wandering a strange city with a stranger’s impulses. We desperately need to develop not only the tools to measure the self, but the language to properly describe it. If we only focus on healing the brain, we risk losing the person inside.