Context dependent latent inhibition in adult humans

Learning the association between one stimulus (a condition stimulus, CS) an d another (unconditioned stimulus, US) can be impaired by prior exposure to the CS alone-latent inhibition (LI). Current theories attempting to elucid ate the cognitive deficit in schizophrenia have used the abolition of LI in schizophrenia as an indicator of attentional dysfunction. However, it has always been unclear if human and animal LI are measuring the same psycholog ical processes. It is obviously important to clarify this relationship so t hat theoretical and experimental developments in the rat do not mislead the investigation of brain-behaviour relationships in schizophrenia. LI in the rat is strongly dependent upon context. Our aim was to examine the context specificity of LI in humans and specifically to: (1) investigate whether p articipants' belief that they are in a different context is sufficient to a bolish LI, even though there is no physical change in the environment; (2) produce a context manipulation that is immune to alternative interpretation in terms of stimulus generalization decrement; and (3) investigate whether a "tonic" change of context reduces or abolishes human LI, thus complement ing previous reports using a "phasic" change of context. In two experiments we manipulated context in either the real world or a virtual world, and sh owed that LI is abolished by a change of context in adult humans.