Evoked potential decrements in auditory cortex. I. Discrete-trial and continual stimulation

In experiment 1 cats were exposed to sets of clicks (trials) with 1 min inter-trial-intervals to determine if the effects of repetitive stimulation on potentials evoked in the auditory cortex would be cumulative despite discrete-trial stimulation. Evoked potentials were averaged to give one average evoked potential (AEP) for each trial for each electrode; there were four cortical electrodes per subject. To test for dishabituation pawshocks were given between trials 60 and 61. Subjects were paralyzed to insure stimulus constancy. The latency and peak-to-peak amplitude of each component of each AEP was measured; significant amplitude decremented; and decrements were more frequent in components with latencies greater than 15 msec. A few amplitude increments and latency changes were also observed...