STIMULUS CONFIGURATION, SPATIAL-LEARNING, AND HIPPOCAMPAL FUNCTION

Schmajuk and DiCarlo (Psychol. Rev., 99 (1992) 268-305) introduced a n eural network, which utilizes a biologically plausible backpropagation procedure, to describe configural paradigms in classical conditioning . The model correctly describes many experimental results under the as sumption that aspiration lesions of the hippocampus eliminate (a) the competition between simple and configural stimuli to gain association with the unconditioned stimulus and (b) the adjustment of initially ra ndom configural stimuli. The present study extends the network to desc ribe place learning. Under the assumption that ibotenic acid lesions o f the hippocampus only impair the adjustment of initially random confi gural stimuli, the model correctly shows that ibotenic acid lesions mi ght spare a configurul discrimination but impair place learning. In ge neral, the results are taken to support a hippocampal role in the modu lation of stimulus configuration.