For years, memory research has been concerned with theoretical and functional distinctions between explicit and implicit memory. The performance of neurologically-impaired populations on direct and indirect measures of memory has varied depending on the particular experimental paradigm, type of task used, and specific processes engaged during both study and test phases. One theoretical question that has been raised in the literature concerns whether explicit and implicit memory may rely similarly on structures such as the hippocampus and surrounding medial temporal lobe for certain types of implicit memory. While findings largely suggest that priming for preexisting information is independent of such regions, results are much more inconsistent with regard to implicit memory for novel memory representations. To this point, the majority of conclusions have been based on research in patients with amnesia. The varying degrees of severity and locus of damage across studies have made it difficult to make precise statements regarding the role of the hippocampus in implicit memory. The current proposal will provide additional data on this issue through application of explicit and implicit memory paradigms to a population of patients with temporal lobe epilepsy (TLE) who have well-defined medial temporal lobe lesions. Specifically, we will investigate the ability of TLE patients to show explicit and implicit memory for novel item specific and associative information. Performance on these measures will be correlated with available anatomic data that includes hippocampal volumes and subfield cell counts. This research will serve to further elucidate the role of the hippocampus in mediating explicit and implicit memory.
| Leritz, Elizabeth C; Grande, Laura J; Bauer, Russell M (2006) Temporal lobe epilepsy as a model to understand human memory: the distinction between explicit and implicit memory. Epilepsy Behav 9:1-13 |
