The observation that ondansetron and other 5HT3 antagonists (tropisetron, granisetron, dolasetron) improve the ability to filter (gate) irrelevant stimuli and enhance visual information processing in animal models, is of potential therapeutic relevance as sensory gating deficits are a robust neurophysiological marker of psychosis in humans [24–26]. The gene discussed is HTR3A; the disease is psychotic disorder.