[Analysis of the activity of fibers in an entire nerve trunk and a study of impulse frequency in sympathetic preganglionic fibers].


The firing rate in type "B" preganglionic sympathetic fibers during strong pressor reactions varied in different fibers from 0 to 80/sec. With an increase of the pressor reaction, the maximum of the density of frequency distribution shifts from 30--40 to 50--60/sec, previously "silent" fibers becoming involved.