Role of Auditory Cortex in Cued Sound Discrimination of Simple Tones During Immediate and Remote Memory Recall

Fear memory has survival value by helping an organism recall harmful environmental stimuli and/or predict danger. Importantly, although emotional memories serve a highly adaptive function, they can become maladaptive when there is either inaccurate, reduced, or excessive fear memory representation. For example, innocuous sounds abnormally associated with threats trigger inappropriate responses in patients suffering post-traumatic stress disorder (PTSD). Yet the mechanisms underlying this problem remain unresolved. Moreover, the role of the auditory cortex (AC) in cued fear learning is controversial and not well understood.  The purpose of my thesis is to investigate the role of the AC in cued sound discrimination of simple tones and determine if silencing principal cells in this region leads to over-generalization of fear memory recall. I found that bilateral silencing of principal cells in AC led to increased generalization (i.e., poor discrimination of safe and fearful sounds). However, silencing the AC during remote memory recall only produced marginal effects that were evident at all later remote time points. My results suggest that the AC is involved in both discrimination and generalization of simple tones associated with threat and safety during recent and remote memory recall.  .