BRAIN - MY ARCHITECTURE !!

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The brain mappers have at least a rough outline of my primary functioning areas : vision in the rear, hearing on the sides. The most interesting discovery is the pleasure centre. Teach a rat to press a switch that gives a minute electrical prod to the pleasure centre and the animal will press the switch almost continuously preferring the stimulation even to food, given time, it could die of starvation-presumably happily.

I reside, of course, in a well-protected fortress. The skull is about half a centimetre thick at the top, and even thicker at the base. I am bathed in a watery fluid that cushions me from shocks. A blood-brain barrier serves as a gatekeeper letting some things in, denying entrance to others. Thus, it welcomes the glucose I need, but blocks out bacteria and toxic substances. Most painkillers and anaesthetics pass in with ease - but so, unfortunately, do alcohol and hallucinogenic drugs that wildly distort my normal activities. I may even hear a visual image.

Lift a piece of sod from a lawn and note the baffling intertwining of roots. I am something like that - multiplied by millions. Each of my 30 billion nerve cells, or neurons, connects with others - some as many as 60,000 times !! A neuron looks something like a spider attached to a filament. The spider is the cell body, the filament the axon, the legs the dendrites. The legs pick up a signal from adjacent neurons, pass it to the body; the signal is in turn passed along by the filament at speeds up to 340 k.m.p.h. After each signal passes, it takes the filament about 1/2000 of a second to recharge itself chemically. At no point does one of my neurons touch another; signals are passed spark-gap fashion. At each firing one nerve chemically communicates with another.