The permanence of ECS effects in a one-trial discriminated avoidance paradigm

Abstract

Postleaming tests were conducted on the 1st or 30th and 31st days after a single discriminated avoidance trial. Although significant effects on choice latency produced by ECS were not observed on the day after training, statistically reliable ECS-produced reductions in choice latency were apparent on the 30th and 31st days after learning. No statistically significant effects of ECS on discrimination or defecation rates were observed on any postleaming test. In marked contrast to data produced by passive avoidance experiments (e.g., Spevack, Rabedeau, & Spevack, 1967), recent research has indicated that the effect of ECS on both discrimination and latency measures of a one-trial discriminated avoidance task is constant for a variety of leaming-ECS intervals between 100 sec and 20 h long (Suboski, Spevack, Litner, & Beaumaster, 1969b). The authors concJuded on the basis of these and subsequent data (Suboski, Black, Litner, Grenner, & Spevack, 1969a) that ECS effectively interferes with memory consolidation only if the convulsion follows learning within 30 sec. The constant ECS effects they observed for longer leaming-ECS intervals they attributed to ECS effects other than those on memory. One such frequently reported result of ECS (e.g., Brengelmann, 1959) is a temporary deficit in the performance of well-leamed tasks produced by aseries of postleaming convulsions. A notable characteristic of this ECS-produced performance decrement is that it slowly dissipates with time, indicating that it is not due to a disruption of memory storage processes. Such an ECS effect may weil account for Suboski et al's atypical results. To test this possibility, the present study, unlike previous attempts to assess the permanence of ECS effects (e.g.,