Delta-9-tetrahydrocannabinol impairs visual recognition memory but not discrimination learning in rhesus monkeys.
Psychopharmacology 1988 DOI: 10.1007/bf00172964 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Monkeys |
| Intervention | delta-9-tetrahydrocannabinol (THC) |
| Dose | 2 and 4 mg/kg; up to 16 mg/kg |
| Duration | 21-day period of repeated administration; 3-5 day period beginning 7-10 days after last dose |
| Measures | delayed nonmatching-to-sample, 24-h concurrent discrimination learning |
| Topics | Cannabis |
| Key findings | Acute THC at 2 and 4 mg/kg significantly impaired visual recognition memory in monkeys, with impairment lasting through 21 days of repeated 4 mg/kg dosing and during a 3-5 day period beginning 7-10 days after the last dose. By contrast, 24-hour concurrent discrimination learning was not impaired even at doses up to 16 mg/kg. The authors suggest THC interferes with recognition memory more than discrimination learning, possibly reflecting a selective action on limbic mechanisms. |
Abstract
The effects of orally administered delta-9-tetrahydrocannabinol (THC) were evaluated on two different learning abilities in monkeys. Visual recognition memory, known to depend on limbic system integrity, was tested by means of delayed nonmatching-to-sample and found to be significantly impaired by acute administration of 2 and 4 mg/kg THC given 1 or 2 h prior to testing. Performance was significantly impaired throughout a 21-day period of repeated administration of 4 mg/kg THC and also during a 3-5 day period that began 7-10 days after the last dose of THC. By contrast, 24-h concurrent discrimination learning, a task that monkeys with limbic lesions can perform normally, was not impaired by THC, even following doses as high as 16 mg/kg. These results suggest that THC interferes with recognition memory more than discrimination learning, possibly reflecting a selective action of THC on limbic mechanisms.