after stable discriminative performance was obtained ( > 95 % correct ) , groups were administered one of several treatments which lower the concentration of serotonin ( 5-ht ) in brain : ( 1 ) 12.5 , 25 , 50 , 100 or 200 microgram of 5,7-dihydroxytryptamine ( 5,7-dht ) intraventricularly ( ivt ) ;
C0086045
concentration
C0006104
brain