Abstract
Justification is felt in advancing a new analysis of the time-intensity relations for electrical stimulation as it is much simpler mathematically than any existing general analysis and therefore more useful in planning and co-relating experiments while at the same time it fits, as well or better, the experimental data of the Lapicques.
The derivations are based on the following hypotheses: (a) The rate of growth of the local excitatory process whose magnitude is designated by p is proportional to the applied voltage, (b) The tissue has a reaction toward normal at a rate proportional to p. (c) When p reaches a liminal value h excitation is accomplished. 20 The differential equation expressing (a) and (b) is,
when the rheobase, R, is substituted for kh. All the direct current data in Lapicque's book 3 fit the equation,
very well, C being usually positive. With the newer data of Lapicque, 1 , 2 the fit is as good, C being positive sometimes, sometimes negative, frequently zero. The new data indicate that C depends on the type of electrodes used.
In the following examples of the agreement of the equation with Lapicque's data the values marked with asterisk were used to calculate the constants.
The second example is typical for fluid electrodes in that C = 0, or is small. This was also pointed out by Lapicque. 1 He derived, at one time, 4 an expression equivalent to the above equation using a leaky condenser model.
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