NOTICE: Posting schedule is irregular. I hope to get back to a regular schedule as the day-job allows.

Wednesday, April 20, 2011

Mailbag!  [Full link to images for email clients]

All the LabRats are dancing, there's questions in the mailbag! Well, most of the LabRats are dancing - Ratface is just sort of wobbling around and Nestor got tangled up in the electrical cord for the disco ball!

OK, Ratley, bring over that heavy mailbag.


What do you mean there's only one?


Oh, well, even one will do. Hand it here, please.


What?!?  Oh, well - [sounds of brushing, sweeping, vacuuming, washing, rinsing, more sweeping...]
Sorry about that, YDR* (*YouDirtyRat) seemed to think the mailbag was a laundry bag.  Now that I can actually see the handwriting, let me see what we have here...
Um... yeah...
Yes... good one.

Okay,  S.C. is a writer and wants to know what signs and markers might be present if an alien technology caused a person to develop heretofore unknown mental abilities. She asks if there are proteins, other markers, and any way to find out other than by spinal tap (shudders).


Yes, Ratley, S.C. already figured out that there would be headaches.


That's okay, and yes, the question has a real application, and scientists do know how to look for changes in the brain.  Tell you what, Ratley, you give the answer while I get Ratface unstuck from the letter slot...

[Squeak, squeak, squee, squick, squee-eeek!]


Thanks, Doc!

Okay, S.C. you mentioned thinking of something similar to what happens when muscles develop, and that's a good analogy.  See, we actually know a lot about what happens when a human - or LabRat - learns something new.

First, there is a principle that was first published by Donald Hebb in 1949.  We call it "Hebb's Rule" and it states that for any neuron that is active - that is firing off action potentials (the "lightning" as Speaker likes to call it) - if the inputs to that neuron become active, then the synapses - connections between the neurons will become stronger.  Think of an input and an output.  If they are both active, then the connection between them gets stronger.  If you have a way to make *sure* that both are active, then you "teach" the synapse to become more active under that condition.

We now know that this is really an oversimplified idea, and it doesn't always work this way, but it is a pretty good description of a mechanism we call "plasticity" and is an important part of learning and memory.  In particular, making new connections is how memory is stored, but it's also the way baby brains develop into adult brains, and how brains recover and rehabilitate after injury.  The key feature is that the synapses - the connection between the axon of one neuron and the dendrite or soma of its target neuron - are changed: they become bigger, there are more receptors for the chemical neurotransmitters, there is more neurotransmitter synthesized, the gap becomes smaller, and the connection with the rest of the neuron becomes larger.

And we can detect that.

First off, there are gene changes. Proteins are being made.  We can see those by sampling some cells, grinding them up and doing some lab bench work.

Yeah, icky, and worse than a spinal tap.  Trust me, on that.

Well, we see more electrical activity.  You can get that by putting a wire recording electrode next to the neurons, but some signs are visible in the EEG recorded from the scalp.

The process requires oxygen, and oxygen requires blood flow.  We can track that in a number of ways, but the most important is a technique the docs call "functional magnetic resonance imaging."  Those big old MRI machines can actually find which brain areas are using the most oxygen and superimpose that on a picture of the brain.  In 3-D, and you don't even need those awful glasses.

The process also requires glucose, and there's good ways to track that, too - Positron Emission Tomography - used in clinics to look for cancer and in labs to study brain activity.  PET as it is called, would be a good way to look for anything abnormal going on.

OK, Speaker's back, Ratface's tail is bandaged and I'd better go find out what scheme Ratfink is involved in.


Thanks, Ratley!  Now that Ratface is out of trouble - for the next 2 minutes - I'll mention something that Ratley probably didn't realize - the really smart guys who develop new MRI techniques have figured out a way to use it for spectroscopic analysis.  Those proteins and factors that we formerly needed to "grind and bind" the cells to study?  Well, maybe not for long.  MR spectroscopy has a lot of promise to being able to track different types of chemical activity.

So, SC - the short answer is that we could look for many of these signs of *plasticity* and they'd give a suggestion that something new was happening in the brain - and we won't necessarily need a spinal tap to do it!  Of course the splitting migraines and headaches and fainting for no apparently reason would tell us that *something* was happening, but these techniques could give us a better idea of what and where.

Thanks for asking, thanks for reading, and remember folks, questions from the readers are always welcome.  Besides, the LabRats so seldom get a chance to dance, with their cute little formal gowns and tuxedoes...


1 comment:

  1. Don't know if you saw these, but apparently we're learning more about anxiety (and stress)


    (I mostly know about this because I work at NAIST, and have a google alert set to notify of articles mentioning NAIST...)


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