The effect of a 72-h intertrial interval on the 1-Hz suppression effect in rats

Abstract

An experiment was conducted. to evaluate the effect of a 72-h intertrial interval of I-Hz brain stimulation on kindling behavior induced by 60-Hz sine-wave stimulation. The effective threshold intensity (ETI) to elicit a kindled response with 60-Hz stimulation was determined on four separate occasions with 15 trials between determinations. Experimental rats were stimulated. with I-Hz sine waves before and after a 60-Hz brain stimulation trial with a 72-h interval between stimulation sessions (1-60-1 group). A second group received only the 60-Hz stimulation on the same trials as those on which the 1-60-1 group was stimulated with 60-Hz current (X-60-X group). In previous experiments with I, 3, or 24 h between trials, the 1-60-1 group had a gradual increase in the intensity required to elicit a kindled response with 60-Hz current from ETI l to ETI. (the suppression effect). However, the 72-h interval produced a decline in ETI values similar to that of the X-60-X group, but not as great. Suppression of kindled behavior on daily trials was not present for the 1-60-1 group, in contrast to results of previous experiments. Apparently, the 72-h interval allowed much of the suppression effect to dissipate.

The effect of 5- and 14-day intertrial intervals on the 1-Hz suppression effect

“…duced greatly (Gaito & Gaito, 1981) . When the interval was increased to 72 h, the effect had dissipated (or nearly so) (Gaito, 1982). Thus, there appears to be a decay of the effect over time.…”

An evaluation of different methods of producing the 1-Hz suppression effect

“…The effect was present with a 24-h interval but was reduced greatly (Gaito & Gaito, 1981). When the interval was increased to 72 h, the effect was minimal (Gaito, 1982). With 5 or 14 days, the effect appears to be minimal also (Gaito, research in progress).…”

The suppression of kindling with low-frequency brain stimulation: Statistical data with duration variable

“…With 1-and 3-h intertrial intervals, the suppression effect was pronounced. The effect was present with a 24-h interval but was reduced greatly (Gaito & Gaito, 1981); the effect was lost, or nearly lost, with 3-, 5-, and 14-day intervals (Gaito, 1982(Gaito, , 1984.…”