Abstract
Utilizing the action potential as the indicator of excitation, the changes of the irritability in the nerve caused by subliminal current were detected. For the test shock, brief shock from induction coil was employed.
A rectangular current of subliminal strength evokes rapid increase of the irritability in the nerve. The irritability curve ascends at first rapidly and reaches its maximum after 5 msec., then descends gradually to a final equilibrated state.
An exponentially increasing current causes, also, the increase in the irritability in the nerve. In this case, the irritability curve has its crest. The final balanced states of irritability curves are similar, notwithstanding the CR-variances of increasing currents, if their final voltages are the same. The smaller the CR becomes, the shorter the ascending part of the irritability curve and the higher the maximum point of the curve becomes.
The final equilibriated state of irritability depends only upon the final voltage of the current. If a large CR is chosen, the irritability reaches gradually the final balanced state ; and there appears no maximal point.
When the CR is kept constant, the irritability curves reaches their maximal points simultaneously regardless of the final voltage, but the height of the final state is subjected to the final voltage.
When a discharge current of subliminal strength is used for conditioning, the irritability at anodal region decreases rapidly to the minimal point, and returns slowly to the normal level thereafter.
An algebraic summation of the irritability curves of rectangular current and reverse discharge current is approximately equal to that of the increasing currents of the same CR.
