Psychological and Brain Sciences Brown Bag Seminar: Ryan Lingg & Krista Wahlstrom
Psychological and Brain Sciences Departmental Brown Bag Seminar
Ryan Lingg, Psychological & Brain Sciences, The University of Iowa
Neural Circuits Modulating Memory Consolidation of Emotionally Arousing Events
Abstract: A key means of long-term behavioral adaptation to a stressful experience involves producing lasting memories of the event, as this enables the evaluation and appropriate behavioral selection in response to a future stressor of the same or similar kind. Critical to this process is the integration of multiple stress-related signals (e.g. neuroendocrine, autonomic, behavioral) converging upon limbic-cortical consolidation networks, which convey the degree of emotionality to be encoded. Using optogenetics in rodents, we have identified a prominent role for the anteroventral subdivision of the bed nuclei of the stria terminalis (BST) in regulating the influence of endogenous stress signaling during consolidation of an emotionally arousing event. Specifically, functional optogenetic interrogation of BST and related circuitry identified bi-directional modulation of memory consolidation via neuroendocrine-dependent and independent mechanisms, driven by neuroanatomically dissociated downstream effectors. Collectively, these results position BST as a regulatory locus responsible for coordinating the influence, and the degree to which, these stress-related signals contributed to memory consolidation. This talk will highlight the specific BST-centered circuits involved in modulating memory consolidation, as well as whether BST activity within a broader systems level context may provide insight into a variety of stress-related behavioral phenotypes.
Krista Wahlstrom, Psychological & Brain Sciences, The University of Iowa
Role of the Basolateral Amygdala in the Modulation of Spatial Memory
Abstract: Previous work on multiple memory systems suggests that spatial learning is mediated by hippocampus-based systems and that the basolateral amygdala (BLA) modulates the consolidation for this type of learning. The medial entorhinal cortex (mEC) is a critical region in the hippocampus-based system for processing spatial information and, as an efferent target of the BLA, has been shown to be one of the mechanisms by which the BLA influences spatial learning. Therefore, the present study elaborated on previous work from our laboratory showing that optically stimulating activity in the BLA-mEC pathway enhances the consolidation of spatial learning. The current study examined whether optically stimulating the BLA-mEC pathway following spatial training alters the expression of ARC (activity-regulated cytoskeleton-associated protein), a plasticity-associated protein important for memory consolidation, downstream in the hippocampus. To address this question Sprague-Dawley rats were trained on the spatial version of the Barnes maze task, directly following which they received optical stimulation of the BLA-mEC pathway. The rats were sacrificed 1 h after the start of training and brains were removed and flash-frozen and tissue punches were collected for ARC protein analysis. Western blot was used to determine the density of ARC protein in the dorsal hippocampus. Results revealed that there were higher levels of ARC in the dorsal hippocampus of rats that received optical stimulation of the BLA-mEC pathway compared to control animals. These results reveal a mechanism by which BLA-mEC stimulation enhances spatial memory in rats.