Circadian rhythm in rat H-reflex.
We measured soleus H-reflex in the Sprague-Dawley rat as a function of time of day. H-reflex amplitude displayed a marked diurnal variation, even though background EMG and M-response amplitude were stable through the day. The H-reflex was largest in the late morning and smallest around midnight. Thus, its rhythm was opposite in phase to the circadian rhythm found in the primate H-reflex. This rhythm is a potentially confounding factor in studies of motor function. Furthermore, its existence implies that the CNS activity underlying a specific motor performance varies with time of day.
Chen
X Y
XY
Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany.
Wolpaw
J R
JR
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D004567:Electrodes, Implanted; D004576:Electromyography; D006181:H-Reflex / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley