Neuropsychological and neurophysiological bases of function in associative learning in schizophrenia:

Associative learning is studied with the use of a conditioned blocking task (CB), from the paradigm of 'learned inattention'. The task examines the extent to which reponses to redundant elements of the task (a computer-game) are inhibited, as might be expected (i.e. selective attention). There have been a number of neurobehavioural studies of the contribution of certain brain areas and neurotransmitter function to CB in animals, but there have been very few investigations of human subjects.

In this programme, we compare the demonstration of CB in healthy subjects with the normal and abnormal performance of patients with different forms of schizophrenia. The intention is to describe some of the neuro-psycho-biological processes that modulate normal associative learning, and to provide an indication of which of these may function abnormally in specific types of schizophrenia.

The types of schizophrenia are expected to reflect broadly patients with the psychopathological emphasis on symptoms of reality distortion, disorganization or poverty in acute, chronic or remitted form. These subgroups are expected to show different patterns of CB. Associations of these patterns with plasma indices of dopamine, noradrenaline and serotonin metabolism and binding will be sought. Further, a neuropsychological exam with 8 tasks should provide information as to which pattern of learning or which subgroup of patients shows impairments on tasks implicating (lateralised) dysfunction in the areas of executive abilities (frontal lobe), spatial-attentional function (parietal lobe) and memorial abilities (temporal lobe).