I love my job.
Aside from it being intellectually stimulating and allowing me access to all kinds of smart folks and good technology and all that, every once in a while my job affords me the opportunity to experience things that most people don't ever get to experience.
I was invited to observe brain surgery.
My boss wanted to ensure that I really understood the design of an experiment that I was helping him write about. It just so happened that the experiment in question was being performed on people undergoing brain surgery. So it was that I was whisked off to the observation deck of the operating room.
Much of the work of neuropsychologists is devoted to finding ways of measuring neural activity without having to hack out bits of people's skulls. Electroencephalography and magnetoencephalography measure the tiny changes in electrical and magnetic fields (respectively) that result from concurrent firing of large neuronal populations by placing detector devices on a person's scalp. The information is collected in real time, and both methods provide a relatively direct measure of the activity of neurons, but the spatial resolution is crappy, and so it is hard to get an idea about what's really going on when people are thinking about stuff. Positron emission tomography and functional magnetic resonance imaging are different methods of tracking metabolic changes in the brain that result from neural activity. These methods feature very good spatial resolution, but it takes about two minutes to record activity. Do you know how many acts of cognition you can perform in two minutes? Have you ever played Boggle? Also, it is unclear whether there is a systematic relationship between the metabolic changes being measured and actual neural activity. Transcranial magnetic stimulation is cool: by delivering a magnetic pulse to a small area of the brain, it is possible to induce a temporary functional lesion. In other words, you can make a bit of brain stop working for a little while. This technique has good temporal and spatial resolution, but it has been known to cause seizures in people who never had seizures prior to the magnetic stimulation. Also, the process is somewhat painful (imagine someone repeatedly hitting a small spot on your head with the back of a pen), which limits the attention your experimental subjects will pay to whatever test it is you are forcing them to do.
My point is that all of these methods fall into one of two categories: 1) you get to know what the neurons are doing, but not where they are doing it, or 2) you get to know where something is happening, but not much about the neural activity causing it.
This is the most frustrating thing of all.
Of course, at some point, some fresh-faced electrophysiologist, all pumped up from recording electrical signals from the giant axons of squid neurons, said something along the lines of, "hey, wouldn't it be neat if we just stabbed a human in the brain with an electrode?"
Enter single unit recording.
Single unit recording is so unbelievably cool. Doctors take a tiny, tiny electrode and shove it into someone's brain (either into a single neuron or in between a couple of neurons), and then ask them to do stuff while they record the firing pattern of anywhere from 1 to 4 neurons simultaneously. So, you get to know exactly what the neurons are doing, and where they are doing it. Best of both worlds, except that, since you are STABBING someone in the BRAIN, it is a procedure that can only be performed on a person when they happen to have a big hunk of exposed brain, and should probably only be done to neural tissue that was going to be removed for some other reason, anyway.
So, anyway, because people are interested in direct measures of neural activity, and because my boss wanted me to understand what I was writing academic papers about, I found myself standing about 15 feet away from someone's exposed temporal lobe. As if this wasn't amazing enough, the patient had been awakened so that the neurosurgeons could perform tests of her language, motor, and sensory abilities in order to locate which brain bits they should make an effort not to cut out.
My first articulate thought upon viewing the operating room was something along the lines of, "wow, that looks sort of like whipped cherry jell-o, except for the bleeding and moving." It seemed like it bled more when the patient was asked to do something that required thought. There were way too many doctors in the operating room, and they were all talking too casually about how much hippocampus to remove (yeesh, that's essentially someone's memory that you're talking about cutting out!). It was disturbing to consider how much damage was being done just in the act of determining how to inflict the least damage. And, of course, the fact that the surgeons labeled the functionally important bits of cerebral cortex with what amounted to tiny post-it notes only added support to my notions that a) there are some areas of medicine that have progressed very little in the past 100 years and b) science would fail without post-it notes. But the one thought that stayed with me long after I had left the intensity of the hospital was that I am so grateful that there is a thick piece of bone between the harsh sharpness of the world and the soft, lumpy, and all-too vulnerable organ that makes me who I am. I hope I am never in a situation where that protection is compromised.
I do feel better equipped to write about the experiment now; my boss was correct in thinking that nothing but seeing it for yourself would really drive home what the procedure was like. I also have a lot of respect for neurosurgeons, nurses, and anesthesiologists; it was clear that they were responsible for whether this person continued to live or not. I think I might be inclined to drive a little more slowly. And while watching the surgery made it clear that it was important to avoid things that can harm your brains from the outside, I can't help but consider all the things I can do to reduce the amount of damage that I am doing to my brain from the inside.
I respect my head.
Wear a helmet!