Implications from studies of the nucleus accumbens: toward a multi-factor theory of schizophrenia

A model is propose of dopamine and histamine modulation of afferent hippocampal activity in the nucleus accumbens. It is suggested that increased dopamine action leads to an increase in the signal/noise ratio or a form of contrast enhancement. To the contrary, the effect of an increased histamine action would be to inhibit the most salient incoming hippocampal message; i.e., a form of contrast reduction.