ACUTE EFFECTS OF METHYLENEDIOXYMETHAMPHETAMINE (MDMA) ON SEVERAL COMPLEX BRAIN FUNCTIONS IN MONKEYS

The effects of MDMA were assessed in rhesus macaques using behavior in an operant test battery (OTB) consisting of five food-reinforced task s designed to model aspects of time estimation, short-term memory, and attention, motivation, learning, and color and position discriminatio n. Testing occurred 30 min after intramuscular. injections of MDMA (0. 0, 0.1, 0.3, and 1.0 mg/kg). The behavioral endpoints monitored includ ed percent task completed, response rate or latency, and response accu racy. Percent task completed was significantly decreased in the time e stimation, learning, and motivation tasks at 1.0 mg/kg as compared to saline controls. Response accuracies in the time estimation and learni ng tasks were also decreased at 1.0 mg/kg. Response rate was decreased at 1.0 mg/kg in the motivation task but was not significantly affecte d in any other tasks. No behavioral endpoints were significantly affec ted in the short-term memory and attention and color and position disc rimination tasks at any dose tested. Results indicate that time estima tion, motivation, and learning are more sensitive to the acute effects of MDMA than are short-term memory and attention and color and positi on discrimination.