UBC Theses and Dissertations
Memory storage : evidence that consolidation continues following electroconvulsive shock Mah, Chun Jew
Recent experimental evidence indicates that the effectiveness of posttraining electroconvulsive shock in disturbing retention is not constant but highly variable. One factor which appears to contribute to this variation is the strength of the electroshock current. Currents of higher intensity or of longer duration have generally been found to be more effective in disturbing retention. Indirectly, this evidence suggests that an electroshock treatment does not invariably stop memory consolidation. It appears that following a weak electroshock treatment, the interference with consolidation is not complete and that consolidation may continue afterwards. This possibility was directly examined in the present experiment with a one-trial passive avoidance task. The results showed that rats given one electroconvulsive shock 5 min after the passive avoidance training suffered only a slight loss of retention. However, when a second electroconvulsive shock was given at 1 hr after training, there was a significantly greater retention loss than that following one electroconvulsive shock at 5 min or at 1 hr. Additional results indicate that the disruptiveness of the second electroconvulsive shock is time-dependent and that the retention deficit does not appear to be due to punishing or disinhibitory effects of the electroconvulsive shocks. These findings are interpreted as indicating that memory consolidation can continue after electroconvulsive shock.