Abstract
The association of contextual fear memory (CS-US association) occurs when a conditioned stimulus (CS) is paired with an unconditioned stimulus (US). When the association occurs, many brain regions are thought to be inter-connected each other and form a complex network. Thus, CS-US association may occur in many brain regions that receive convergent CS and US inputs. In this study, we employed a behavioral paradigm, context-pre-exposure facilitation effect (CPFE) paradigm, in which mice received paired or unpaired presentations of the CS and US during conditioning. Using this behavioral paradigm, we performed Arc catFISH analysis to detect brain regions required for the CS-US association and found that basolateral amygdala, hippocampal CA1, prefrontal cortex, piriform cortex, entorhinal cortex, anterior cingulate cortex, ectorhinal cortex, sensory cortex, visual cortex, and retrosplenial cortex that responded to CS-US signals. Furthermore, we found that the number of CSUS responsive neurons significantly increased in basolateral amygdala, CA1, prefrontal cortex, piriform cortex, and entorhinal cortex of paired group. These results suggest that these brain regions regulate the CS-US association of contextual fear memory.
