Friday, October 23, 2009

The cerebral cortex is not in the neck.

Here's one that simply amazes me.  Someone brought this to my attention a little while ago, but it took me some time to track down.  In the tv show "The Unit", one of the members of this secret counterterrorism group gets killed.  His name was Hector, and I guess it was a big ratings ploy in season 3 where they leaked that someone from the unit was going to be killed. Hector was shot through the neck by a sniper, and the bullet ultimately winds up being lodged in his chest cavity somehow.  Ignoring the fact that the bullet made a magical U-turn to end up where it did, I am more perplexed by the scene in the show where the medical examiner tells one of the other members of the unit that "the bullet entered the neck here, snapping the cerebral cortex.  He felt no pain."  In the scene, the guy even points to the cervical portion of the spine (the neck) as he is saying the phrase "snapping the cerebral cortex".  I hate to break it to the writers of "The Unit", but the cerebral cortex is in the brain, not in the spinal cord.  Sort of like an onion, the brain has several layers, except, unlike an onion, the brain tends to be bigger and more squishy and wrinkly.  Just like the tough outer skin on the onion, the brain has a tough protective skin called the dura mater (which basically means "one tough mother", dura is the latin word from which we derive the word durable, and mater, means mother, like in alma mater, which means "nourishing mother", a term we honor our colleges and universities with since they nourish us with scholarship).  Under the dura mater is the arachnoid layer which doesn't really resemble anything you'd see in an onion, but looks more like a collection of spiderweb-like structures (thus arachnoid) which helps to cushion your brain against collisions with the inside of your skull.  Beneath the arachnoid lies the pia mater ("soft mother"), and, together, these three layers make up the meninges (which may sound familiar if you've heard of meningitis, which is an infection characterized by the swelling of the meninges.  Meningitis can be bacterial or viral, and in some cases, usually when it is bacterial, meningitis can be fatal, which is usually when it shows up in the news).  Directly under the meninges lies the cerebral cortex.  It is the outermost layer of what we typically think of as the brain: the gray, wrinkly ball that sits in the skull.  The cerebral cortex is actually the part of the brain that gives it its gray and wrinkled appearance, and it is also an area that is very important in most of our thinking, feeling, and doing.  The image below gives you some idea of the cerebral cortex, though it might be a little tough to read, I recommend going to the site I took it from: to get a better look.  Once you get below the cerebral cortex you hit subcortical structures like the basal ganglia (of which, the striatum is the largest portion), and even the cortex itself is subdivided into many layers (6 in the human brain).  Though, unlike an onion, or the picture, most of these layers are not so easy to pull apart, and they are more distinctions that have been made by looking at the tissue under a microscope than an onion like layering.  All of that being said, I'm not saying that getting shot in the neck wouldn't kill you, especially if it severed the spinal column, and, if that were the case, then it is possible that you wouldn't be in much pain (at least you probably wouldn't feel much below the point at which the spinal cord was separated), but I think you're cerebral cortex would remain intact.

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