LSD accelerates Pavlovian learning in rabbits

Injections of the psychedelic drug lysergic acid diethylamide, commonly known as LSD or acid, accelerates Pavlovian learning in rabbits by desensitizing certain neurotransmitter receptors, according to a published report.

The study, which was lead by Anthony G. Romano of the Drexel University College of Medicine, demonstrated that LSD can enhance the acquisition of eyeblink conditioning by desensitizing specific serotonin receptors located in the dorsal hippocampus, a region of the brain associated with learning and memory.

"The serotonin 2A receptor (5-HT2A) has been implicated in the production of hallucinations in humans and cognitive effects such as enhanced acquisition during autoshaping in rodents, enhanced acquisition of trace eyeblink conditioning in the rabbit, and enhanced working memory in the non-human primate," the authors of the study write.

Eyeblink conditioning is a type of Pavlovian conditioning that involves pairing an auditory or visual stimulus with an eyeblink-eliciting stimulus, such as a small puff of air to the eye. After repeatedly pairing an auditory or visual stimulus with an eyeblink-eliciting stimulus, the animal eventually learns associate the two stimuli and will blink after being presented with only the auditory or visual stimulus.

This type of conditioning is used by researchers to investigate the neural mechanisms that underlie learning and memory.