Dr. Deisseroth is a Professor of Bioengineering and of Psychiatry and Behavioral Sciences at Stanford University, board-certified by the American Board of Psychiatry and Neurology, and an investigator at the Howard Hughes Medical Institute. After receiving his undergraduate degree from Harvard and his PhD/MD in a combined program from Stanford, he completed postdoctoral training and continued as a practicing psychiatrist at Stanford with specialization in affective disorders and autism-spectrum disease, employing medications along with neural stimulation. He is best known for creating and developing the field of optogenetics.
It is the first chapter of Dr. Deisseroth’s new book that I want to focus on, titled Storehouse of Tears. In it he describes an encounter as a medical student on his pediatric rotation at a children’s hospital. It was midnight when he got wind of a late emergency transfer from arriving from an outside hospital. It was Andi, a four-year old girl whose parents came in with her clutching a brainstem scan. The doctor of record, the pediatric neuro-oncology attending, was brought in not to perform a procedure, but to explain the conclusions from the team’s physical exam and the reading of the film. Andi had acute onset esotropia with diplopia, always a worrisome sign. Deisseroth writes:
“The double vision was not a mystery to us. There was a finding on the scan. A shadow had fallen across her pons. At the stem of the brain, at the base of the skull, there is a bulge of cells and fibers called the pons – dense and vital, connecting all that makes us human in the brain above to the spinal cord and nerves that leave the skull below. If within the pons – Latin for bridge – a disruption has appeared in the path of the fibers passing through, physicians can see this happening without a CT scan or MRI: no medical imaging, just human imaging, just looking into the eyes of the human being …
… Abducens, the simple sixth, is one nerve serving one muscle, the lateral rectus muscle with its one job – abducting the eye. The abducens lies entirely on one side of the brainstem, its threads coursing deep through the heart of the pons, carrying out their singular duty. But now, tonight, abducens was playing another role, reporting back on something unnatural in the brainstem, telling a tale of a thing gone wrong – and on the film. confirming the diagnosis, we could see that a form, a darkness lay across the bridge.”
Sadly Andi’s diagnosis was a diffuse intrinsic pontine glioma (DIPG), a death sentence in which she was given only six to nine months to live. It ripped Karl’s heart out, leaving him with emotions akin to the feelings I had about losing Stephanie, a teenager with acute onset esotropia secondary to brainstem glioma. As beautiful as Karl’s writing is throughout the chapter, the following paragraphs about binocular vision may be the most lyrical description you’ll read from a non-optometrist other than Sue Barry:
“This coordination between eyes is a lovely thing when it works, when they join to face the world together in primates like us. Both receive the same information from the brain to follow the ball thrown from Dad in the darkening chill. But the two eyes, each with slightly different shapes and angles, are not connected to each other. Much has to be perfectly tuned for the two eyes to move together, to not create double vision with offset views of the same scene.
This challenge is especially pleasing to bioengineers as a paradigm of the need for design. Such synchrony and symmetry in biology, when achieved, imply trust, and truth, and health. Two sensors, two eyes, are balanced together on the finest edge of time. There are always failures of communication in biological systems – noise, chaos, there is even sometimes profit in deception – so every system needs feedback to check and calibrate. Early in life, before we become aware, double vision serves as the error signal sent back – and then our brains mend the error, adjusting the instructions transmitted down cranial nerves to the eye muscles, aligning and tuning with care, until the offset disappears, and we see the world as one.
The world becomes whole, until a falsity returns in some – it was here tonight in this little girl, and here it could never be trued. When a member of the pair slips infinitesimally, an intruder is revealed, and a sickness known; the nerve fibers through the pons become more and more disrupted, as the shadow spreads. Here it could have been no other cranial nerve, it was abducens, sixth nerve of twelve; in this brainstem cancer, it is always the sixth: alert and direct, a border division reporting without fail the first faint hoofbeats of invasion.”
Several weeks ago, Dr. Deisseroth was the first guess of the Huberman Lab Podcast. After making it through the commercials at the outset for glasses and probiotics, beginning at the 7:40 mark of the video above, Dr. Andrew Huberman (professor of neurobiology and ophthalmology at Stanford featured in our last blog) conducts an enthralling interview with Dr. Deisseroth well worth the two hours of viewing time that it spans. To help navigate through the video, if you don’t have the time to view it in one sitting, there is time stamping of topics that is available here.