Poster D127, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
Structural Integrity Deficits of Uncinate Fasciculus Predict Medial Temporal Lobe Subfield Activity During an Emotional Pattern Separation Task
Steven Granger1, Stephanie L. Leal2, Elizabeth A. Murray1, Michael A. Yassa1; 1University of California, Irvine, 2University of California, Berkeley
The human medial temporal lobe (MTL) is well known to contribute to the storage and retrieval of episodic memories. Recent evidence shows that the dentate gyrus (DG) and CA3 subfields of the hippocampus contribute to a neural computation known as Pattern Separation which the brain uses to distinguish between highly similar items (known as “lures”) during recall. A similar paradigm, known as the Emotional Pattern Separation task has been employed to study the effects of emotional discrimination in both healthy and in those exhibiting depressive symptoms. We have previously shown that during this task, depressive symptoms drive an effect where DG/CA3 subfield activity decreases whilst amygdala activity increases during correct discrimination of negatively-valenced lure items. Although the MTL’s functional activity has begun to be categorized during these Pattern Separation tasks the role of the prefrontal cortex (generally thought to exert top-down influence over cognitive processes) is still relatively unclear. The uncinate fasciculus (UF) is one of the major white matter bundle connecting the prefrontal cortex and MTL. Further, deficits in the UF have not only been implicated in those exhibiting depressive symptoms but they also have been shown to correlate with memory performance in tasks involving highly similar items. Here we tested the hypothesis that deficits in UF would predict the emotional pattern separation signal observed in depression. We found that strength of connection of the UF predicted a decrease in both amygdala and DG/CA3 activity during correct lure rejection of emotional items.
Topic Area: LONG-TERM MEMORY: Episodic