 Schizophrenic patients exhibit impairments in filtering of sensory information, as can be assessed by use of prepulse inhibition PPI of the acoustic startle response and P50 suppression paradigms. In the treatment of negative symptoms or depressive syndromes during the course of schizophrenia antidepressants are often combined with antipsychotic medication. However, antidepressants increase monoaminergic activity, of which in turn it has been suggested to decrease sensory gating, although these presumptions are mostly based on results from animal studies. Currently, little is known about monoaminergic modulation of sensory filtering in humans, and the few reports that can be found in literature show discrepancies with animal studies. The current study was designed to study the effects of increased monoaminergic activity on sensory filtering and habituation of healthy volunteers. In a double-blind, placebo controlled cross-over design, twenty healthy male volunteers will receive either placebo or a dose of 50 mg of imipramine a dual acting antidepressant, after which they will be tested in a P50 suppression-, a PPI-, and a habituation of the startle reflex paradigm. 