Cannabis, atropine, and temporal information processing

In experiment 1, subjects judged time by duration production under no-counting instructions. The productions were made following intravenous injection of atropine sulfate or saline, and after smoking cigarettes with and without (-)-delta 9-tetrahydrocannabinol (THC). THC increased the subjective time rate (STR); i.e., the rate at which subjective time passes relative to clock time, whereas atropine had no effect on STR. Thus, reduction in central acetylcholine activity is not a sufficient explanation of THC's effect on STR. Experiment 2 replicated the THC effect on STR when subjects were counting subjective seconds. This result indicates that THC affects the experience of time as it is passing, and not solely the memory for duration experience after a time period.