Stress-induced fear memory generalization: c-fos analysis in amygdala and hippocampus

OTAMENDI A.; BENDER C; MOLINA VA

Cordoba

Congreso; XXXIII Congreso Anual SAN; 2018

We have previously demonstrated that stress prior to fear conditioning favor the generalization of fear in anon-pairedcontext (cxt-B) which is differentto the conditioning context (cxt-A). The aim of this work was to analyze the c-fos cell expression in amygdala and hippocampus, with the aim to detect some differential activation pattern that could underlie the stress-inducedfear memory generalization. The restraint stress session was performed one day before the fear conditioning. The memory test (cxt-A)or generalization test (cxt-B) were performed 24 after conditioning and one hour later their brains were fixed. Then,c-fos immunohistochemistry were performed and the number of c-fos positive cells wascounted in different regions of hippocampus (CA1, CA3, DG) and amygdala (LA, BLA, CeA). We observed an increase of c-fos positive cells in LA and BLA of conditioned rats (with or without prior stress) exposed to the training context, indicating an increase of the activity in basolateral amygdala complex during the retrieval of fear memories. Surprisingly, no differential activation was observed in the hippocampus in any of the groups tested. Animals that were exposed to the generalization context did not show any difference either in amygdala or hippocampus.In conclusion, the current results indicate that under our experimental parameters no differential pattern of c-fos activation in amygdala or hippocampus is associated with the generalization of fear memories.