or the upregulation of 5-HT1A receptors in the brains of subjects with schizophrenia. The augmented tonic stimulation of postsynaptic 5-HT1A receptors, as a result of the increased number of these receptors, may be a reason for impaired cognitive function in patients with schizophrenia. Activation of presynaptic 5-HT1A autoreceptors by low-dose 5-HT1A partial agonists, by means of inhibition of 5-HT neuronal activity, would produce a greater degree of decrease in the stimulation of postsynaptic 5-HT1A receptors in patients with schizophrenia compared with psychiatrically normal subjects. Thus, low-dose 5-HT1A agonists improve memory function in patients with schizophrenia but not in normal subjects. 5-HT: 5-hydroxytryptamine. Redrawn from.[92]