Atmospheric Circulation of DDT

active facilitation. It might also be argued that the drug was operating on consolidation processes. Since it is generally assumed that consolidation is a progressive stabilization of a memory trace over time, our data suggest that this labile phase of memory lasts for at least 5 days. That there was a trend toward facilitation in the LD(l) group supports this contention. The same trend, however, appeared in the LD(5) group. Thus we would have to postulate not only that the labile phase persists for at least 5 days, but also that there is equipotentiality of the memory trace throughout this time period. These assumptions are not supported by previous investigations, which found no evidence of retrograde facilitation of memory when the drug was administered at intervals beyond several hours after training (1-3). Furthermore, the consolidation argument can be vitiated since neither the LD(1) nor the LD(5) group differed significantly from the control group in this study. It is conceivable that the observed facilitation could be attributable to performance factors unrelated to memory. For instance, the repeated drug administration could have increased motivational, arousal, or attentional levels. Further, activity levels as well as sensitivity to the white and dark alleys could have been altered. If, however, any of these variables were responsible for the reported enhancement, it is likely that the naive groups given strychnine would have been similarly facilitated. Since strychnine was facilitating only to animals that had received prior exposure to the maze, the most reasonable interpretation of these results is that strychnine influenced the long-term store of memory. There are several ways in which strychnine could have produced the observed enhancement. The drug could have strengthened the informational representation of the training experience or could have retarded the decay of that representation from the long-term store (prevention of forgetting). Alternatively, strychnine may have increased the accessibility of information in the long-term memory store (enhancement of retrieval processes). At present, these alternatives cannot readily be distinguished. It should be noted that some investigations of facilitation of memory have employed repeated administrations of the analeptic compound over many days.