Gradient of interference by various frequencies on 60 Hz kindling behavior.

An experiment was conducted to evaluate the effect of various frequencies of brain stimulation on kindling behavior induced by 60-Hz sine wave stimulation. The effective threshold intensity (ETI) to elicit a convulsion was determined on four separate occasions with 5 days of daily trials between determinations. On each day experimental rats were stimulated with current of a specific frequency on the first and third trials for 60 seconds duration and with 60-Hz current for 30 seconds on the second trial (one hour intertrial interval). There were five experimental groups, one each for 1, 5, 10, 30, and 60-Hz stimulation. A sixth group received no stimulation on trials 1 and 3 and 60-Hz current on trial 2. Suppressor of convulsive behavior induced by the 60-Hz stimulation trial was present for all ETI determinations with 1-Hz and 5-Hz stimulation; the mean ETI increased on each successive determination. Suppression was prominent also for the 10-Hz group until the ETI4 determination. Suppression was moderate for the 30-Hz and 60-Hz groups. Overall, it appeared that the interference effect gradually increased with remoteness from the 60-Hz point.