Abstract
As an approach to understanding of the peripheral effector mechanisms of the galvanic skin reflex (GSR), impedance changes were measured at the palm and dorsum of hand on 17 healthy male adults with special reference to COLE'S circuit. The measurement was conducted with sinusoidal current of nine different frequencies ranging from 30 to 10, 000c/s and with low frequency square pulses.
1. At each frequency of sinusoidal currents, resting impedance of the skin was measured with the result that impedance locus for each frequency was found to occur fairly well on a circular arc as was expected from the assumption that COLE'S circuit is suitable as equivalent to impedance of the skin.
2. By means of Lissajous' figures, changes in resistance, in reactance and in absolute value of impedance were measured at each frequency of the sinusoidal currents. It was found that resistance of the skin decreased at lower frequencies and increased at higher frequencies, whereas reactance always decreased irrespective of frequency. In spite of this variation in resistance change, the absolute value of impedance always decreased, although to a progressively lesser extent with increase in frequency.
3. On the basis of these experimental results and of the results obtained by analyzing the traces of the impedance loci during the GSR, it was suggested that impedance change of the skin during the GSR may be only due to decrease of the leakage resistance R2 of COLE'S circuit.
4. In the experiment with square pulses, initial resistance, initial capacitance and residual resistance were measured from the polarization curves during the GSR. Residual resistance decreased markedly without any appreciable change either in initial resistance or in initial capacitance. These results are in agreement with those obtained by the use of sinusoidal currents.
