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The neuroscientist's brain

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Monday
Mar202017

My kitchen tends towards maximal entropy

My favorite definition of life is a system that, thanks to metabolism (energy transfer) and self-organization, is capable of keeping itself at a dynamic equilibrium away from the ultimate equilibrium: maximal entropy, or total disorder.

My kitchen, like everything else in life, also tends inexorably towards maximal entropy - and it takes a lot of work to constantly keep it from reaching it. It would be a living system, if it weren't for the lack of self-organization and metabolism. In their absence, I do the part of keeping my kitchen organized and functional.

The very workings of a kitchen generate disorder, heat and waste products that tend to accumulate if not actively removed. Producing a meal out of meats and vegetables, like assembling proteins from amino acids, requires mobilizing machinery and supporting actors that tend perniciously not to return to their places on their own. Dishes, glasses and cutlery barely make it back into their drawers and cupboards and they are dirty again. Tending to the kitchen is like being the ATPase on call, incessantly hustling sodium and potassium, dishes and glasses uphill against their natural gradient, against their tendency to stable equilibium, total disorder, maximal entropy. Remove the ATPase from the system and it inexorably converges towards the final, stable equilibrium: death.

Living - like keeping an organized kitchen - is the fine art of holding your balance away from the final balance.

Monday
Apr062009

I've seen my own brain!

...and it is gorgeous, with all the gyri and sulci it's supposed to have! It has a callosum, a caudate, ventricles (a bit on the biggish side, but I won't complain) and a lovely, text-book like brainstem. There's my hippocampus, next to the inferior horn of the lateral ventricules, right where I tell my students to look for it! There are my red nuclei, so conspicuous! And what a beautiful cerebellum!

As you can tell, I showed up last Wednesday to volunteer for Jorge Moll's fMRI research on attachment - that is, the emotional bonds we form with loved ones. After ten years of writing about neuroscience for the general public, I was finally about to take part in a research using functional brain imaging and to discover what it feels like to slide into the magnetic field of one of these big machines. I felt like a child going to Brain Disneyland.

There was an informed consent formulary to be filled out, in which I declared being aware that I was free to leave the study at any point; that I would be exposed to a strong magnetic field, and no, I didn't carry any non-removable metallic items in my body; that my data would be presented in scientific papers, albeit devoid of personal identification; and that I would receive, upon completion of all tasks, the images of my brain and a full radiologic evaluation (although the clinic was not obliged to provide any health care that might be necessary, in the unlikely but possible event of finding, say, a tumor or an aneurism about to explode in my brain - which, I was happy to find, does not seem to be my case).

"What is this deafening noise? Is that the machine?", I asked. Yup, that's it: that's the sound of the magnet being repositioned several times every second, during the exam, in the room nextdoor. Inconvenient, but necessary, since that is what allows the machine to image brain activity in every nook and crany of the brain during the exam and compare it over time and across conditions.

And these were the conditions: 200 different phrases describing situations in which I was supposed to imagine myself and press a button for "pleasant" or "unpleasant". That alone would last about one hour, after which they would acquire purely anatomical images of my brain for another half hour or so (and, in the meantime, show a movie to distract me while I kept my head immobile for a while more: would I rather watch E.T. or Finding Nemo?). They would then give me dinner, and hand me a bunch of personality inventories to fill in before letting me go. Ok, then - ready for the pajamas?

Oh, yes, I had thought about that part on the drive down to the clinic: No buttons, zippers or other metallic attachments allowed in the machine, much less earrings or other pieces of jewelry. I could already picture myself in a very unflattering, green hospital gown - the kind that shows one's tushy in the back. But none of that: the clinic provides comfortable, warm and very decent grey flannel, long-sleeved pajamas, and even flannel "shoes". Much better. I could fall asleep in those clothes.

Instants later, I was being invited to lie down in the gurney that slides into the machine. Three or four pairs of expert hands placed a pillow beneath my knees (I'd like want one of those in my own bed, please), a panic button in my left hand ("press three times to call us"), the response buttons taped to my right leg and hand (don't want that falling down in the middle of the experiment), and little cushions around my head, to hold it in place. And down came the harness around my head, with the rear-view mirror that would allow me to watch the screen behind the tube... and into the tube I went.

That's the bizarre part: the feeling of having one's brain's electrical activity being momentarily screwed up by a strong magnetic field, which by definition generates its own electric field. It felt like my body was sinking, my brain going numb. Maybe this is what a panic attack feels like, I thought - so I swept through my mental records about MRI machines: their magnetic field remains on all the time, and one must slide slowly into it, lest stars appear in the examination room's sky. So I comforted myself thinking that what I felt was probably real (I once read that some researchers at CERN, in Switzerland, were amusing themselves bobbing their heads into the magnetic field of the synchrotron to "get high"). I breathed slowly and deeply for a while to help my brain calm down, just in case.

And then... I gave my very own and intimate contribution to neuroscience: I let them examine how my brain reacts to phrases like "you read a story to your one and he falls asleep in your arms", "you get distracted and lose your child in the park", and control phrases like "you arrive at work and turn on the computer". Two hundred of them. Reading in the mirror was fine; it even helps one forget one's current, improbable location inside a tube (which is actually quite short and not that scary). Even the noise was bearable, especially since it is rhythmic (and my toes danced to it throughout the exam - one side effect of over a decade of musical training).

What I had not expected was that a side effect of immobility, rather than immobility itself, would be almost unbearable: the urge to scratch my nose, my head, my legs. As the machine vibrates, it feels like some kind of mechanical energy builds up under the skin... and it took great self-control to think of something else other than the itch (I bet my anterior cingulate was really active during those phrases!). The breaks in the sequence were a relief: "Are you ok in there, Suzana?" Yes, but may I pleeeease scratch my nose now?

And then, when all forms had been filled, clothes had been changed and good-byes already said... "Hey, would you like to see your brain now?"

Of COURSE I'd like to see my brain! I'm a neuroscientist, for heaven's sake, how could I ever turn down an offer to confirm that I, indeed, do carry a thinking brain inside my head? Somebody else was already in the tube, but the kind and understanding technician pulled my image files and started to slide the mouse over my virtual head. "Look at that, this is you without any hairs!" (thanks, but no, thanks; I much prefer the hairy version of me). And there they came, all sagital, coronal and horizontal sections of me, one ear to the other, top to chin, front to back. There they were: my grey matter, my white matter, my striatum - I actually have all that in my own brain! And look at the ventral striatum, so clearly discernible, I was teaching about it this very morning! Look, my insula, my hippocampus - Hey, that's my claustrum! And the red nuclei, wow! (It seems that this particular commentary was a first: they had never heard anybody compliment their own red nuclei. That's what they get for showing a neuroscientist her own brain!).

Of course I instantly asked Jorge, and he kindly agreed, also instantly: he'll grant me access to all files for me to use them in my neuroanatomy classes and upcoming textbook. How great is that gonna be: I can soon point to the screen and use my very own brain to teach!

 

Monday
Feb022009

Stream of thought

I catch the subway at Penn Station, NY, to visit a neuroscientist friend before heading back home to Brazil, my hands occupied trying to keep the suitcases upright, my head distracted, floating from one loose thought to the next - when I notice the dark blue tiles on the wall of a station: 59th street. The association is immediate and inevitable, and The 59th Street Bridge Song springs readily to mind, two voices, guitar and all:

"Slow down, you move too fast/we've got to make the morning last/just kicking down the cobblestones/looking for fun and feeling groovy..."

I've known this song by heart since my teenage years, when most of my English vocabulary came from Simon & Garfunkel songs (and Agatha Christie's crime novels; I had a most peculiar vocabulary). So I sing the cheery words of the song all the way uptown, from Queensboro to my destination, on 168th Street - where any remains of the song are driven away from my mind by more prosaic going-ons regarding how to negotiate subway doors and hallways while carrying two suitcases, a handbag, and a case of brains (yes, primate brains, from Jon Kaas's lab, where I had been the previous weeks) all by myself. The subject at hand is, all of a sudden, an entirely different matter.

As William James would put it,  the thoughts that occupy our conscious mind follow one another constinuously, like the stream of a river, without interruptions. Some stem from within, from our own internal processes, desires, memories, and projections for the future; but here and there some external stimulus bursts in, and for some instants draws the stream of thought to itself, bringing to surface the memories and emotions associated with it - like the joy that surfaces along with the words to the 59th Street Bridge Song. And so, hopping from association to association, with my stream of thought occasionally interrupted by this or that chance event, by my own memories, and by those pertaining to my currrent target, on Haven Avenue, I arrive at my destination. The mind wanders around, but it keeps its course.

 

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