MDMA enhances associative and nonassociative learning in the rabbit.
Pharmacology, biochemistry, and behavior February 1994 DOI: 10.1016/0091-3057(94)90012-4 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Intervention | MDMA |
| Dose | 0.95, 1.9, and 3.8 mg/kg |
| Duration | 10 sessions |
| Topics | MDMA |
| Key findings | MDMA enhanced associative learning at doses of 0.95 and 1.9 mg/kg but not at 3.8 mg/kg, with the effect most pronounced when light served as the conditioned stimulus. MDMA also increased the amplitude of the unconditioned response to a corneal air puff across 10 sessions, which the authors interpret as sensitization. The authors argue this dual enhancement of conditioned and unconditioned responding may be unique to phenylethylamine drugs like MDMA and MDA. |
Abstract
The rate of associative learning was assessed in the presence of saline versus methylenedioxymethamphetamine (MDMA) at doses of 0.95, 1.9, and 3.8 mg/kg. The conditioned stimuli (CSs) were lights and tones and the unconditioned stimulus (US) was a corneal air puff. Learning was enhanced by all but the highest dose of drug tested, and the enhancement was most pronounced when light was used as the conditioned stimulus. Nonassociative responding was assessed using unpaired presentations of the lights, tones, and air puffs. MDMA (1.9 mg/kg) produced a slight increase in the percentage of baseline responses but failed to produce an increase in the frequency of nonassociative responding in the presence of the lights or tones. MDMA produced a significant increase in the amplitude of the unconditioned response to the corneal air puff across the 10 sessions. This increase was taken as evidence for sensitization of the unconditioned response, a nonassociative learning phenomenon. In summary, MDMA, like the parent compound methylenedioxyamphetamine (MDA), enhances both conditioned and unconditioned responding. Because this dual effect has not been seen with related psychedelic compounds, the effect appears to be unique to this class of phenylethylamine drugs.