Fig 7 Measurements of membrane time constants as

Fig. 7. Measurements of membrane time constants as a means for estimating the electrical dimensions of muscle cells in the innervated muscle preparation. A: slow and fast PSPs are displayed together with a low-amplitude passive response to current injection. PSPs are single events, the passive response is an average. Three responses are normalized and aligned at the peaks. Fast s. PSP and the passive potential have a similar decay time course, whereas the slow PSP decay is significantly slower. B: semilogarithmic plot of the decay phases shows a similar behavior for the fast and passive potentials. After ∼ 10 ms, the decay can be fitted with a single exponent corresponding to the membrane time constant. Slow PSP also can be fitted by a single time constant but longer than that of the passive potential and fast PSP. C: example for the distribution of s. PSP half-decay time (the time from peak to 50% amplitude) as a function of s. PSP rise time. Fast s. PSPs have a decay time similar to the average half-decay of the passive potential (→), whereas the slow s. PSPs have broadly distributed half-decay times. D: summary of 6 experiments showing the correlation between the half-decay time of the passive potential and those of the fast and slow s. PSPs. Error bars indicate SD. Linear regression line has a slope of 0. 966, indicating similar half-decay of the passive and fast s. PSP. Slow s. PSPs have much longer and broader distribution of half-decay times. DOI: (10. 1152/jn. 2000. 83. 3. 1315)