The Role of the Hippocampus in Delayed Match- and Nonmatch-to-Sample Tasks

Studies of human amnesia and animal lesion studies have identified the hippocampus and the adjacent, anatomically related cortex, including entorhinal, perirhinal, and parahippocampal cortices as important for memory processes. However, the role of the hippocampus within this medial temporal lobe memory system is controversial. This thesis attempts to clarify the role of the hippocampus in memory. The question of whether the hippocampus is involved in memory, more specifically in visual recognition memory was addressed. Subjects, adults of ages 20-29, performed three different tasks: a delayed match-to-sample task (DMS), a delayed nonmatch-to-sample task (DNMS), and a color counting task, which served as a control condition. The stimuli used for the paradigm were adapted from the delayed nonmatch-to-sample task of the CANTAB (Cambridge Automated Neuropsychological Test Battery; Robbins, et al. (1994)). Event-related functional magnetic resonance imaging (ER fMRI) was used to gain insight into the temporal course of hippocampal activation