Effects of diazepam on closed- and open-loop optokinetic nystagmus (OKN) in humans.
The effects of diazepam on optokinetic nystagmus (OKN) eye movements were studied under closed-loop and open-loop conditions in healthy humans. The open-loop condition was achieved by adding the eye-movement velocity signal of OKN to the computer-generated signal controlling the moving stimulus grating. Each of four subjects received a single oral dose of 5 mg diazepam or a placebo on two separate days in a double-blind randomized fashion. OKN eye movements were measured 90 min after administration of the treatments. As compared to placebo, diazepam significantly reduced the gain of open-loop OKN, but did not modify the gain of closed-loop OKN. The results indicate that the OKN gain under the open-loop condition is a more sensitive detector of the parameter changes of the OKN system than under the closed-loop condition. Thus, open-loop OKN gain can provide an objective, quantitative measure of benzodiazepine agonist effects.
D000328:Adult; D003975:Diazepam / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D017120:Nystagmus, Optokinetic / Q000187:drug effects* / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods*
D003975:Diazepam