Arguably one of the greatest contributions to modern day neuroscience was made in 1953 by Henry Molaison, a 27-year-old man who suffered from debilitating epilepsy.
The summer of that year, a surgeon in Hartford, Conn., removed two slivers of Molaison’s brain, an attempt to quell the seizures. The seizures subsided, but Molaison was left lacking the ability to record new memories, a case of severe anterograde amnesia that revolutionized our understanding of how memory works and helped establish the science of it.
Epilepsy and patients like Molaison have frequently been at the center of breakthroughs in understanding the mysteries of the brain. It is a window that has allowed researchers unparalleled access to unearth the ways in which the structure and functions of the brain inform its psychological processes.
One of the most common neurological disorders, epilepsy is really a large number of syndromes, all characterized by recurrent seizures. Sometimes medication can keep a condition under control, other times surgery is necessary, removing the brain tissue or lesions responsible for seizing.
Surgery is where epilepsy provides science with unique entry into the brain.
Much has been gleaned – often, as in the case of Molaison, unwittingly – from actually cutting into the brain in the course of treatment.
The studies of the brain in preparation for surgery, though, have also been crucial to research.
“If you trace back most major findings, it all ends up beginning with patients with epilepsy,” said Dr. Josef Parvizi, a Stanford neurologist who specializes in the disorder.
In a paper published last week in Nature Communications, Parvizi was among a team of Stanford doctors to uncover the latest nuances of brain functionality. The study utilized a technique increasingly employed by doctors called intracranial electrophysiology to detect the precise areas of the brain in which seizures begin.
Doctors implant dozens of tiny electrodes under the skull, directly onto a patient’s brain. The level of functional detail doctors receive as a result is unmatched.
Parvizi and company were able to pinpoint the pattern of brain activity that occurs when people think quantitatively.
With the technique, researchers can measure the ultrafast and extremely subtle electrical reactions of the brain’s neurons as they fire away at an extremely high resolution. So, when, for example, a patient thinks about numbers, researchers can see exactly which areas of the brain are stimulated.
Other methods of recording brain activity, such as functional magnetic resonance imaging or electroencephalography, along the surface of the scalp, don’t provide the same level of detail, though those methods have also yielded important discoveries on their own.
Their research was performed on the brains of three patient volunteers already under evaluation for surgical treatment of epilepsy. After all, it is not without legitimate occasion that scientists endeavor to slice into someone’s skull.
Parvizi’s team took their research one step further, recording patients while they were conscious and going about their business in the days in the hospital prior to surgery.
“Monitoring patients with epilepsy through intracranial recording really is the only direct window we have into the conscious human mind,” he said.
An understanding of the brain’s activity pattern when engaged in quantitative thought might seem like a relatively small discovery, but such discoveries add up and begin to provide a more complete picture of how our mind is linked to the brain’s physical structure.
Another Parvizi study of epilepsy patients published last fall uncovered two nerve clusters in the brain that are critical to perceiving faces. At UCSF, a study published in February mapped the parts of the brain which control lips, tongue, jaw and larynx as a person speaks and showed how those parts of the brain work together during speech.