Abstract
In an attempt to study the effects of heart beat on MT (minor tremor, physiologic tremor), the changes in MT, its auto-and crosscorrelogram and frequency spectrum before and during bradycardia and cardiac arrest induced by right unilateral vagal stimulation were observed in fifteen adult male rabbits.
Vibrations in the autocorrelograms of the MT of both thighs in the control states before and after section of the right vagal nerve were reinforced rhythmically at the same rate with the heart rhythm. Quite the same timepattern was observed in the crosscorrelograms of the R spike in EKG (electrocardiogram) and the above MT, wherein each reinforced swell was induced approximately60msec after the R spike suggesting that the rhythmical reinforcement is driven by the heart beat. The reinforced vibration was higher in its frequency than that of heart rhythm. Enhanced vibrations in the autocorrelograms of the MT and their frequency spectra were observed even by such a weak vagal stimulation that produced hardly and distinct changes in the EKG and MT ink records.
A moderate vagal stimulation to induce bradycardia caused depression of most MT during the elongated resting period of the heart beat, but there was augmentation of some MT. Immediately after initiation of bradycardia, several heart beats were strengthened, each of which was accompanied by anenhanced MT. This verifies the above finding of rhythmical reinforcement of MT. Cardiac arrest induced by slightly strong vagal stimulation was accompanied by depression of MT in most instances, but there was enhancement of some MT. Even when the raising changes in MT were initiated by bradycardia and/or cardiac arrest, depression of MT was noted in the average patterns (autocorrelograms of MT and their frequency spectra) for sustained vagal stimulation of 35 or 48 sec.
