Connectionist simulations with a dual route model of fear conditioning

The dual route model of fear conditioning, developed by LeDoux (1986, 1996), was investigated in four simulations within a connectionist framework using CALM Maps, a competitive learning procedure. We adapted the model and replicated the simulations by Armony, Servan-Schreiber, Cohen, and LeDoux (1995), compared the two models and finally focused on functional differences between the two routes. Extinction due to interference by intervening material could be found in the model. Latent inhibition was also simulated in this model. The relative contribution of both pathways to the behavior of the model was examined in several lesion experiments. It is argued that the computational model may need further extensions to fully implement the functional differences between the two routes in the theoretical model.