An Anatomically Constrained Neural Network Model of Fear Conditioning

Conditioning of fear reactions to an auditory conditioned stimulus (CS) paired with a footshock unconditioned stimulus (US) involves CS transmission to the amygdala from the auditory thalamus, the auditory cortex, or both. This article presents a simple neural network model of this neural system. The model consists of modules of mutually inhibitory nonlinear units representing the different relevant anatomical structures of the thalamo-amygdala and thalamo-cortico-amygdala circuitry. Frequency-specific changes produced by fear conditioning were studied at the behavioral level (stimulus generalization) and the single-unit level (receptive fields). The findings mirror effects observed in conditioning studies of animals. This computational model provides an initial grounding for explorations of how emotional information and behavior are related to anatomical and physiological observations.