Role of the conditioned stimulus input to lateral amygdala in auditory fear memory retrieval

Abstract

During auditory fear conditioning, secondary auditory cortex(AuV) and auditory thalamus(MGm/PIN) convey conditioned stimulus to lateral amygdala(LA). Auditory pathways to LA are well-studied, and LA has important role to recall auditory fear memory. However, role of these pathways during memory retrieval is unknown. To verify necessity of these pathways, inhibiting terminal of auditory pathways in LA area was conducted by two third version of optogenetic techniques

Halorhodopsin(eNpHR3.0) and Archaerhodopsin(eArch3.0). As the result, auditory fear memory was recalled normally during inhibition with eNpHR3.0, while freezing level decrease by inhibition with eArch3.0 during tone release. Furthermore, at another retrieval session after 24-hours (second retrieval), memory retrieval was blocked also. Even mice are conducted re-training, impairment of memory retrieval didn't recover. This impairment is not an effect of cellular damage by virus or over-expression of proteins. According to result of Arch group, I infer that auditory input to LA is required for memory retrieval. For ensuring the state, recoding the activity of input terminal during memory retrieval is needed.