The Roles of the Amygdala and the Hippocampus in Fear Conditioning

The amygdala, a small structure located deep bilaterally in the medial temporal lobe, is the key structure for the emotional processing and storage of memories associated with emotional events, especially fear. The structure has also been shown to enable humans and animals to detect and respond to environmental threats. Fear conditioning became the main model to examine the neural substrates of emotional learning in mammals and specifically in rats’. With the fear conditioning method, researchers can tests rats’, responses to aversive stimuli during the delivery of a cue and then measure how the responses change after learning of the association between the stimuli and the cue. After learning of the two stimuli, the delivery of a cue alone will prompt a fear response in the rats. The fear response can also be elicited by placing the rats in the same chamber in which the aversive stimuli has previously been experienced, which depends on both the amygdala and the hippocampus. Where the amygdala stores the memories of stimulus related to fear, the hippocampus seems to hold all the fear memories in relation to contextual information about the stimulus. The aim of this paper will be to make a comprehensive overview of internal neural processes of both the amygdala and hippocampus and the interaction between the two structures during fear conditioning, to see how the structures separately work to overlap emotion and memory processes.