(no subject)
So, last semester in biochem, we spent one glorious day on the central nervous system and the working of axons and action potentials. After a neuron fires, the axon must restore its electrochemical gradient, and it does this with a protein that pumps 3 sodium (Na) ions out and 2 potassium (K) ions in. The Na builds up outside the cell until the next time the cell fires, and then Na rushes in and must be pumped out again. So my boyfriend and I had wondered whether a gradient of K built up, and if so, how does that affect things? I speculated (or half sorta remembered, seeing as how I'm supposed to be the brain expert between the two of us) that K is permeable to the cell membrane and maybe just diffused outside the cell.
Well, I just read about this cool thing. When there's a great deal of neuronal firing, K concentrations build up outside the cell. Cells called astrocytes (which is a type of glial cell, meaning it has supportive function but doesn't participate directly in mental processing) serve as buffers for K, soaking it up when the concentration gets too high due to increased activity. I also learned that astrocytes actually form a network with one another, allowing them to redistribute K from high-conc areas to low-conc areas in the brain. But what really wowed me was this:
A high K concentration, when exposed to a blood vessel, causes dilation. Astrocytes have processes called end-feet that cover and protect all the nervous system tissue, including blood vessels in the brain. Astrocytes, through their end-feet, expose the high concentration of K that they're absorbing from around hyperactive neurons to the blood vessels, causing the vessels to dilate. So, not only are the astrocytes getting rid of waste matter produced from overactivity of the neurons, but they use the same function to increase blood flow to those same active areas when it is needed most!
How efficient!!
An afterthought: All brain function is dependant on two things: the organization of connections between neurons, and the rhythms of their firings. I wonder, then, if the rhythmic functioning of our brain leads to greater enjoyment of the rhythms in our speech and music.
I'm reading this psych paper on a lark about attachment disorders in childhood abuse survivers. It contains this sentence: "The primary method in the attachment field for measuring resolution of childhood trauma (including childhood abuse and loss) is the Adult Attachment Interview." And then it lists the authors, so you can look the test up in the references and go read the paper or test. The concept is, ya know, VITAL to the reliability of one's information, especially when the test we're talking about is the basis of her whole paper, which it is. But when you look the authors up in the references, it says, "Unpublished manuscript, University of California, Berkeley."
Brilliant.
She should be hunted down and shot.