Emotions induce physiologic arousal that influences the brain to form enduring memories of emotional events. Dr. Almira Vazdarjanova’s research interests are to understand the brain systems and molecular mechanisms that endow emotional memories with their permanence. The main focus of research in the lab is examining how emotional experiences alter the composition and temporal dynamics of neuronal ensembles involved in memory consolidation.
These investigations involve a combination of behavioral, pharmacological and molecular methods which include immunohistochemistry in combination with an immediate-early gene (IEG) imaging method, called cellular compartment analysis of temporal activity using fluorescence in situ hybridization (catFISH). This method has the cellular resolution that can compare, within the same animal, neuronal ensembles activated by two separate behavioral experiences, such as an emotionally-neutral and emotionally-motivated experience experienced in the same physical place. When rats explore a place, they learn about its features. This emotionally-neutral learning is associated with activity-related IEG expression in forebrain neuronal ensembles that process spatial and emotionally-neutral experiences. If the same rats are returned to the place 30 min later and now receive an aversive experience, IEG expression will occur in neuronal ensembles representing the emotional experience. By comparing the neuronal ensembles activated by the two experiences, we can detect which forebrain regions contribute to encoding the emotional significance of a place. We further investigate functional interactions between these regions by pharmacologically inactivating one and assessing the changes in neuronal ensemble representations in the other brain regions.
Furthermore, we study the dynamics of memory consolidation in these brain regions by assessing Arc protein expression within the first 24 hrs after the emotional experience. Arc (activity regulated cytoskeleton-associated protein) is a good marker of synaptic plasticity because it is induced by learning and is essential for memory consolidation. By understanding the temporal dynamics of Arc expression we plan to design effective pharmacological therapies aimed at reducing the probability of developing post-traumatic stress disorder following an intense emotional experience.
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