Neuroscience 2004 Abstract
| Presentation Number: | 708.2 |
|---|---|
| Abstract Title: | Marijuana and timing: Effects of chronic use. |
| Authors: |
O'Leary, D. S.*1
; Block, R. I.1
; Hichwa, R. I.1
1Psychiatry, U of I Hospitals, Iowa City, IA |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Addiction and Drugs of Abuse -- Cannabinoids |
| Session: |
708. Drugs of Abuse: Nicotine and Cannabinoids Slide |
| Presentation Time: | Tuesday, October 26, 2004 1:15 PM-1:30 PM |
| Location: | San Diego Convention Center - Room 3 |
| Keywords: | CANNABINOIDS, TIMING, BLOOD FLOW, ADDICTION |
Altered time perception is one of the most frequently-reported subjective experiences associated with the “high” induced by marijuana (MJ). Intoxicated subjects typically experience time as passing more quickly relative to real time i.e., MJ increases the subjective time rate. We assessed the acute and chronic effects of smoking MJ or placebo cigarettes (provided by NIDA) on a self-paced finger tapping task using a double-blind, placebo-control design. Volunteers (n = 10) who smoked marijuana recreationally an average of 3 times a month (low-use group) were compared with chronic users (n = 15) who smoked marijuana daily for an average duration of 5 years. A tone was presented for 50s with a beat to beat interval of 730ms, and was then turned off. Subjects were instructed to tap in time with the tone and to continue tapping at the same pace for 50s after it terminated. Tone-paced tapping did not change in either group after smoking placebo or MJ, indicating that MJ did not cause sensory-motor impairment on this task. After smoking placebo self-paced tapping did not change in the low-use group, but was significantly slower than tone-paced tapping in the chronic group (tone paced=727.8ms, sd=8.9, self-paced=745.3ms sd=26.1). Chronic use of MJ appears to slow an internal-clock resulting in slower self-paced behaviors. After smoking MJ both groups significantly increased their mean rate of self-paced tapping (by an average of 43.6ms in low-use subjects and by 32.3ms in the chronic group). Acute MJ use appears to speed the internal clock, resulting in changes in self-paced behaviors and altering time perception in both occasional and chronic users. PET imaging data collected in a subset of subjects indicated that chronic use of MJ results in hypoperfusion in the cerebellum at baseline (i.e., after placebo). Blood flow changes in the cerebellum were correlated with changes in tapping performance in both groups, but the pattern of cerebellar activation differed in the two groups.
Supported by 2 R01 DA010551-04A1
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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