Word: neuronal
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...explained that the human mind contains so many neurons that direct observation of neuron behavior is difficult...
According to Dr. Richard Wurtman of M.I.T. and Dr. Nicholas Zervas of Beth Israel Hospital and Harvard Medical School, a large part of stroke injury may be caused by imbalances in the brain's neurotransmitters, the chemicals that carry nerve impulses from one neuron, or brain cell, to another. The doctors base their theory on experiments in which Neurosurgeon Zervas produced massive strokes in 13 monkeys by cutting off blood flow-and thus oxygen-to the left sides of their brains. Examining the brains afterward, he and Wurtman found that there were dramatic changes in the levels of dopamine...
Study in man is vastly complicated by the fact that the human brain contains an estimated 10 billion nerve cells called neurons, and another 100 billion of a second type called glial cells. The fluid bath in which they are suspended is an important element in their electrochemical interactions. Moreover, said Sweden's Dr. Holger Hydén, one big neuron may have on its surface as many as 10,000 points of contact (synaptic knobs) with other neurons (see chart). But by means of exquisitely delicate instrumentation and an electron microscope, Dr. Hydén has discovered that...
Learning About Life. Most scientists now agree that too much was made in the early days of the apparent similarities between computers and the human brain. The vacuum tubes and transistors of computers were easy to compare to the brain's neurons-but the comparison has limited validity. "There is a crude similarity," says Honeywell's Bloch, "but the machine would be at about the level of an amoeba." The neurons, which are the most important cells in the brain, number some 10 billion, and each one communicates with the others by as many as several hundred routes...
...impulse caused by the ear's hearing "concert A" scurries from cell to cell until it finds those containing RNA molecules already keyed to respond to that note, and it is this chemical response that constitutes recognition of the note. The average human brain has ten billion neurons, so the number of possible permutations is astronomical. Further, said Dr. Hyden, this theory explains why neurologists have been unable to find precise centers in the brain for most higher mental functions: through its content of many imprinted molecules, each neuron may participate simultaneously in many neuronal networks-and therefore...