Question

Please give an overview as to how the fear system works from the following perspectives:

• How can an animal be fear conditioned and what are the neural circuits involved?
• How can a human be fear conditioned?
• What is the process of extinction and what are the neural circuits involved?
• How does the amygdala modulate declarative memory formation?

Answer 1

Fear conditioning is a simple form of associative learning, where an animal learns to associate the presence of a neutral stimulus, called the conditioned stimulus (CS), eg a light or a tone, with the presence of a motivationally significant stimulus, called the unconditioned stimulus (US), eg an electric shock to the foot.Intra-amygdala circuit is involved in fear conditioning. The neurons in the basolateral amygdala are responsible for the formation of conditioned fear memory. These neurons project to neurons in the central amygdala for the expression of a conditioned fear response.Neurons in the basolateral amygdala are responsible for the formation of conditioned fear memory.The amygdala is related to acquisition, storage, and expression of conditioned fear memory.

Fear extinction is the process of fear reduction through repeated re-exposure to a feared stimulus without any aversive outcome. The fear extinction is coordinated by the mPFC amygdala. The amygdala, a structure in the brain's temporal lobe, attaches emotional significance to memories. It is important as strong emotional memories (e.g. those associated with shame, joy, love or grief) are difficult to forget.