Examining the effects of serotonin on perceptual awareness and attention.

Have you ever noticed that when you look at something with both eyes, your brain picks one image to focus on at a time and switches back and forth? This is called binocular rivalry, and it happens in hearing too. Scientists are studying how a brain chemical called serotonin — which is involved in mood, sleep, and perception — affects how quickly and how often this switching happens. Researchers will give healthy volunteers two different medications that affect the serotonin system and measure how perception changes. You may be eligible if: - You are a healthy adult between 18 and 50 years old - You have no significant health conditions that would interfere You may NOT be eligible if: - You or a close family member (parent, sibling, or child) has a personal history of psychiatric or neurological illness, or suicidal thoughts - You have vision or hearing problems - You have liver or heart problems (including diagnosed high blood pressure) - You are pregnant or breastfeeding - You have had a bad reaction to buspirone, citalopram, or similar medications - You have taken any psychiatric or psychoactive medications in the past 2 weeks - Your blood pressure is consistently above 140/100 at the time of screening Talk to your doctor about whether this trial might be right for you.