CONTEXT EFFECTS IN LEARNING AND MEMORY: HUMAN AND ANIMAL PERSPECTIVES

Contextual changes have been found to influence the performance and expression of a wide range of learning tasks, including classically conditioned and instrumental procedures. However, attempts to uncover the neuropsychological and/or neurobiological concomitants to these demonstrations of context are meagre. In a series of experiments, we have attempted to describe a possible modulation exerted by catecholaminergic pathways upon the role of context in latent inhibition and sensory preconditioning, on the one hand, and spatial navigation and latent learning on the other. In these experiments, noradrenaline and dopamine were depleted either in the adult animal (noradrenaline) or in the neonate. It was found that noradrenergic pathways in the forebrain do influence certain complex tasks, such as latent inhibition and sensory preconditioning. Dopaminergic modulation of spatial learning tasks was demonstrated although the role of dopamine in latent learning was dependent upon the procedure applied (i.e., the number of latent learning trials presented). A tentative discussion of these findings with regard to monoaminergic involvement in the tasks examined is presented and it is suggested that these results may offer the continued development of the context concept within this particular field of endeavour.