zdnet | I'm part of a team that runs studies on humans while they are being monitored with electrodes implanted deep inside their brains. This is unique, allowing us to eavesdrop on the activity of individual nerve cells inside a human brain. We work with patients who have severe problems that require brain surgery, for potential resection of the focus of an epileptic seizure. Most people with epilepsy take medication to reduce the seizures, but a small number of patients are candidates for an invasive surgery [resection] that removes the seizure focus and stops the seizures. You want to find the smallest amount of brain you can resect to stop the seizure. The surgeons put electrodes around the part of the brain that is suspected as the seizure onset site. Then the neurologists can monitor the activity inside the patient's brain and wait until the patient has experienced a number of seizures in the course of a few days while they are in the hospital. One can then monitor the flow of the seizures and isolate the exact source before resecting the site that causes the seizures. Then the surgeons remove the electrodes and resect the part of the brain where the seizures originate. The patient walks away seizure-free.
As researchers, we use this unique opportunity to work with a patient who is awake with electrodes deep inside his or her brain to study cognition. The patients who are in the hospital waiting to have seizures for the doctor are happy to help science by participating in studies. These studies allow us unique access to the building blocks of thought, memories and emotions in a way that is rarely accessible otherwise in humans. There are only a small number of people in the world who have had their brains opened and have participated in studies where scientists recorded directly from within their brain. We ask the patients about their feelings, for example, while looking inside the brain using those micro-electrodes, and we can see how their answers indicate how the brain works. We can map the brain and learn how the brain operates slowly using this unique way, by looking inside the brain of a person who is sitting in front of us.
In one study, we had people look at images. When you look at a picture of, say, your mother, there is a part of your brain that becomes active as you recognize her. Other parts come to life when you think about something else (say, Marilyn Monroe or Big Ben in London). We can decode these thoughts by looking at the patterns that become active when you see an image of one thing and when you later think about that thing voluntarily. We then are able to see what they're thinking of as they think. At the same time, we can decode their current thought on these things and effectively project those to the patients in front of their eyes. You can actually show patients their thoughts. Even more interesting for us is we can look at competing thoughts. We can put two images on the screen and tell them to think of only one of them and see how this competition is resolved inside the brain.