Electrophysiological Studies of the Effect of Rhythmical Sound on the Central Nervous System (Part 1)

Abstract

Electrophysiological studies were conducted in rabbits in order to investigate the effect of rhythmical sound with 120/min beating frequency and 500 Hz pitch,120/min 1000 Hz,220/min 500 Hz and 450/min 1000 Hz, respectively on the central nervous system.
Following were the effects observed.
1. The threshold of arous al reaction evoked by the reticular formation (RF) stimulation was elevated with the sounds of 120/min 500 Hz from the level when the non sound was given. But with the sounds of 220/min 500 Hz,120/min 1000 Hz and 450/min - 1000 Hz, the threshold of arousal reaction dropped compared to the condition of non sound.
2. The threshhold of muscular discharges evoked by the RF stimula t ion were lowered with each of the four sounds compared to the condition of non sound.
3. The muscular discharges evoked by the stimulation on cerebral cortex were inhibited with the sound of 120/min - 500 Hz, compared to the condition of non sound, but were facilitated with 450/min 1000 Hz.
4. The muscular disc harges evoked by the stimulation on hippocampus were facilitated with both of 120/min 500 Hz and 450/min 1000 Hz.
5. The effects on the nociceptive reflex of the s ounds of 120/min 500 Hz,220/min 500Hz and 450/min 1000 Hz were all facilitated compared to the condition of non sound.
6. The effect of the non sound was inhibitory on the M-H wave, where as tha t of the sounds of 120/min 500 Hz and 450/min 1000 Hz were facilitating.
In conclusion, the rhythmical sound with a low freque ncy, low pitch showed an inhibitory effect to the consciousness and the function of pyramidal system. On the other hand, the rhythmical sound with a high frequency, high pitch showed an facilitating effect.
The rhythmical sound had an facilitating effect to the spinal reflex regardless of its frequency and pitch.