抄録
In this experiment, period of exposure to noise was 60 seconds. 5 rabbits were used and the neuromuscular tension was observed from M. masster by surface needle electodes.
Noises were used in different intensities as 80, 90,100 and 110 db as well as in different pitches as 256, 1024 and 4096 cps.
The following results were obtained :
1) The minimum threshold of responses was between 90 and 110 db according to individual differences in sensitivities to noise.
2) The more the intensity of sound was increased, the more the duration and persisting periods of responses were prolonged and the mean amplitude of responses increased. But no significant changes were found in latent periods.
3) The more the pitches of sound were increased, the more the latent periods were prolonged, duration and persisting periods shortend and mean amplitudes decreased.
4) Conclusions :
The influence of noise on living organismus are more marked when the srimuli were of high intensities and/or low pitches.
