The purpose of this project will be to understand the role of the medial temporal lobes (MTL) in the encoding and retrieval of several different forms of memory, using functional magnetic resonance imaging (fMRI). Encoding process manipulations will be used to determine lateralization of memory function, whereas manipulations of the type of associations available during encoding of a stimulus event will be used to delineate the stimulus properties that elicit MTL participation and storage in long-term memory. During fMRI scanning, subjects will perform either a semantic decision, spatial discrimination, facial decision, or combination of semantic and spatial decision tasks alternated with a shape decision baseline task. Performance of these tasks will induce incidental encoding of the relevant stimulus even in long-term memory. Another scanning session will be conducted to test the recognition of the stimulus event in each form of memory task and to determine the MTLs role in the retrieval phase of memory. Within-subject t-tests will be conducted between each target and control task, average activations maps will be produced, and region of interest comparisons will be conducted both between and within groups. The applicant predicts that the MTL will show lateralization of function for linguistic and spatially demanding tasks and that activation of this region will be specific to encoding stimulus events that involve configural integration of intra-stimulus elements in forming the association.
