Calcium activity of basolateral amygadala and CA1 field of hippocampus in mice with normal and impaired memory

Abstract

We studied an impairment of aversive associative memory in the model of context preexposure facilitation effect in mice. It is known that context memory is dependent on hippocampus. Also, the memory of the aversive stimulus applicated in this context is modulated by basolateral amygdala (BLA). However, it is unclear what changes occur in the activity of hippocampus and BLA in animals with impaired context fear memory. In the present study we investigated the calcium activity of BLA and CA1 during context memory formation and retrieval of normal context memory and memory impaired by protein synthesis inhibition. We showed that the BLA and CA1 area were active in moments of mice freezing behavior during the first context exploration (preexposure session). In contextual fear memory retrieval, we observed a decrease in calcium activity in the CA1 area and an increase in BLA activity during freezing in mice with impaired memory. All together, we demonstrated, that context memory impairment leads to a change in the BLA and CA1 calcium activity levels. Such changes are opposite in BLA and CA1. However, further research is needed to uncover the nature of described phenomena.