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The Thalamus - The Kernel in Your Mind
corbettw writes "This article on Yahoo Science News describes a new finding that explains how the thalamus is used by your brain to essentially boot your brain, and provide for central processing and control of all impulses going to and from the cortex. The article describes its function as an operating system, but from the description it actually seems closer to the functions of a kernel." From the article: "The finding, published last week in the journal Neuroscience, changes the way scientists understand nitric oxide's role in the brain, and it also has them rethinking the function of the thalamus, where it is released. The thalamus was thought to be a fairly primitive structure, sort of a gate that could either open and allow sensory information to stream into the cortex, the higher functioning part of the brain, or cut off the flow entirely. Godwin says the new research shows it's more accurate to think of the thalamus not as a gate but as a club bouncer, who doesn't simply allow a huge rush of people to go in or no one at all, but picks and chooses whom to let in and out. "
Does this mean we should call the brain the Brain/Thalamus? It's unfair to give the entire package precedence over the kernel, as one is useless without the other.
I used to study neuroscience. The thalamus is a HUGE bank of relay switches in the brain- all these trunk cables go into it from all over. Basically anything you're paying attention to involves some circuit going through the thalamus, and the way the thalamus works is what limits your ability to focus on multiple things at once. Once something becomes rote- like QWERTY typing or good guitar playing- the thalamus is no longer involved.
I have epilepsy- really bad seizures- and my brain gets really messed up on restarts because it regains function piece by piece. Occasionally I'll be totally conscious (forming some long term memories again), and watching stuff come back online- I can hear, then I can see, then I can recognize things I see, etc. There are intermediate states where I can see but not recognize things. The seizures start in the right temporal lobe, so the right hemisphere is completely screwed up, but if my left brain works I can compensate with higher functions. Usually I'm looking for water fountains because my head is really hot and sweaty after a seizure. I'll find a water fountain and think, is this a water fountain? Well it has a stream of stuff that looks drinkable... it has a thing coming out the side that you can turn... it MUST be a water fountain! I almost pissed on my wife's chair once after somehow figuring it was a toilet. But without thalamic activity I'd never be able to patch right brain functions and send sensory information to the forebrain from the left side. If I'm able to pay attention to something at all, then there is some thalamic function. Recognizing it is a different task.
The ability to form long term memories comes later and is a more distributed gradual process as areas of the cortex recover. I was in this cubicle working once... doing simple stuff like cleaning up someone's crappy code... then I started doing more mentally intense work, and I turned around after an hour or two and noticed my cubicle was a mess. Everyone said, "you had a seizure a few hours ago, don't you remember?"
Recently my brain has been passing through a metastable fugue state after really nasty seizures where I have partial function, but it's not me yet- it's like someone else. I answer yes/no questions completely differently, I don't recognize my wife, I fight with people if they get in my way, and I don't know where I'm going but I'm going somewhere, sometimes out the door. Usually no new memories are being formed; I have to go by what people tell me afterward. Apparently I'm getting better at fooling people in the fugue state because my speech in the fugue is starting to almost sound normal even though I have only partial brain function. One of these days I'm going to regain consciousness in jail.