MOVEMENT-ASSOCIATED NEURAL EXCITATION AS A FACTOR IN SPATIAL REPRESENTATIONAL MEMORY IN RATS

The hypothesis that rats require an attentionlike function arising from integration of exteroceptive and movement-related excitation during the information phase of representational memory-dependent discriminations is proposed. Experiments 1A and 1B (both behavioral) demonstrated the crucial importance of movement-related excitation (angle of turn at T-maze choice point). Experiment 2 showed that, contrary to plausible expectations, ablation of putative posterior parietal association cortex only mildly affected memory. This finding agrees with the notion of a nonspecific mass action-equipotential effect of ablations in nondifferentiated cortex on memory rather than the specific effects resulting from dorsolateral prefrontal ablations in primates. Instead, it is proposed from previous data that the hippocampus integrates movement-related and exteroceptive excitations necessary for representational memory, which is largely restricted to spatial attributes in rats.