THE RELATIONSHIP AMONG MEMORY PERFORMANCE AND HIPPOCAMPAL SUBREGION VOLUMES IN A MEMORY CLINIC POPULATION

Abstract

Medial temporal lobe structures, including the hippocampus, are important for the formation and recollection of memories. Regions of the hippocampus have been found to be associated with specific aspects of memory. Specifically, the CA4 has been implicated in pattern separation, encoding, and recognition of visual information, while the presubiculum has been implicated in memory retrieval. The current study examined the relationship between these hippocampal subregions bilaterally and standard measures of verbal and nonverbal memory in order to evaluate whether these regions predict such memory performance. Participants were drawn from a clinical sample of older adults (mean age = 69.9) seen in a memory disorders clinic (n = 651). All participants underwent a brain MRI as well as a neuropsychological evaluation that included measures of verbal, the Hopkins Verbal Learning Test-Revised, and nonverbal, the Brief Visuospatial Memory Test-Revised, memory. Multivariate regressions were conducted in order to assess whether subregions of the hippocampus predict verbal and/or nonverbal memory, after accounting for the influence of age, gender, and total intracranial volume. Results indicated that age, total intracranial volume, left and right presubiculum and CA4 volumes were significant predictors of verbal and nonverbal memory encoding and retrieval (all p <.005). Gender was not a significant pedictor of memory performance. Results suggest that the volumes of bilateral presubiculum and CA4 are predictive of both verbal and nonverbal memory encoding and retrieval in a memory clinic population. Future research examining other hippocampal subregions and specific diagnostic categories will inform understanding of the contributions of these and other subfields to memory function.