26 October 2008

Brainbeat

I'm standing on the vibrating, billowing hills of the tegmentum. Spherical and star-shaped cells; thin, sprawling nerve fibres; and thick, pulsating blood vessles stretch out in all directions. The ground is thick with receptors; twisting out of the bulging membranes like weeds and crystal algae.

The fluid is thick with glutamate; it envelops the cells, pulls on them, tears on their branches, and they willingly suck the salty fluid. Every few hundred milliseconds they trip eachother over the theshold, fluctuate, and generate a single, synchronized electrical impulse that shoots off along the medial forebrain bundle. It's a tonic, steady beat. Far away in the frontal lobe, that rhythm keeps the cortex active, keeps the thoughts alive, even in dreams.

234 151 dopamine neurons in this lobe. The cells are warm, depolarized, expectant; singing their neverending tonic song at three hertz, with more than usual synchrony. Pulse. Pulse. Pulse. Pulse. Pulse. Pulse. In the distance below, the dark substantia nigra cells warm up to the tune.

There. The steady rhythm is interrupted. The single expected nerve impulse is trippled. Pandemonium. The ground is trasformed as dopamine floods from neighbour to neighbour. Branches extend and reconnect. Entire cell bodies move as gap junctions synapse and pull cell membranes closer together. Again. Another tripplet. The background rhythm is up to four hertz now. Pulse. Pulse. Pulse pulse pulse. And then silence. A whole second passes before the tonic song is resumed and the cells begin to break rank and recover.

Something just happened.
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