A Litre and a Half of Brains

Abstract

In a long-ago folk story an old man stands beside his grandson at the receding margin of the last ice sheet. Pointing back he says,`T he edge was there when I was a boy.''

Problems of Cerebral Vascular Disease. I. General Considerations

“…However, there is a tremendous sense of progress (47). O'Leary's admirable review (47) of the field takes note of hundreds of studies which have been difficult to carry out, highly demanding of experimental skill, and often perplexing in interpretation.…”

“…As read electrically the single wave in a train of waves has a duration of nearly 1 millisecond, and then the fiber is refractory for 5 to 6 m seconds; thus the duty cycle is 10 to 15 per cent. Probably the highest available repetition rate is less than 1000 per second (47). The suggestion has been made that the very high velocity of conduction in modern, myelinated fibers is achieved by saltatory conduction, that is, excitation of a whole segment of the fiber (as between any two nodes of Ranvier) at one time, communicated to the next segment (89).…”