A Computational Model of the Amygdala Nuclei's Role in Second Order Conditioning

The mechanisms underlying learning in classical conditioning experiments play a key role in many learning processes of real organisms. This paper presents a novel computational model that incorporates a biologically plausible hypothesis on the functions that the main nuclei of the amygdala might play in first and second order classical conditioning tasks. The model proposes that in these experiments the first and second order conditioned stimuli (CS) are associated both (a) with the unconditioned stimuli (US) within the basolateral amygdala (BLA), and (b) directly with the unconditioned responses (UR) through the connections linking the lateral amygdala (LA) to the central nucleus of amygdala (CeA). The model, embodied in a simulated robotic rat, is validated by reproducing the results of first and second order conditioning experiments of both sham-lesioned and BLA-lesioned real rats.