Adaptive cardiovascular modifications in the western chipmunks genusEutamias

Summary Although cutaneous type I and type II mechanoreceptors in the cat respond at progressively higher frequencies to increasingly rapid skin indentations of suprathreshold intensity, their thresholds are not lowered when these more rapid stimuli are applied. Since these receptors do not selectively detect rapid stimuli of small amplitude, even though they respond much more vigorously to a suprathreshold stimulus that is rapid, different parameters of the stimulus are signalled depending on whether it is near threshold or clearly suprathreshold.This work was supported by grant GB42643 from the National Science Foundation and by grants NS08769, NS07938 and NS05244 from the U.S. Public Health ServiceThe authors thank John Fisher, Gary Frederickson, Tom O'Leary, Robert Perry, and Jane Burgess for their valuable help.