Neuroscience 2000 Abstract
| Presentation Number: | 773.12 |
|---|---|
| Abstract Title: | Effects of frequent marijuana use on attention-related regional cerebral blood flow. |
| Authors: |
Block, R. I.*1
; O'Leary, D. S.2
; Augustinack, J. C.7
; Boles Ponto, L. L.3
; Ghoneim, M. M.1
; Hurtig, R. R.5
; Hall, J. A.6
; Nathan, P. E.4
1Anesthesia, Univ Iowa, Iowa City, IA 2Psychiatry, Univ Iowa, Iowa City, IA 3Radiology, Univ Iowa, Iowa City, IA 4Psychology, Univ Iowa, Iowa City, IA 5Speech Pathology and Audiology, Univ Iowa, Iowa City, IA 6School of Social Work, Univ Iowa, Iowa City, IA 7Alzheimer's Research Unit, Harvard Univ, Charlestown, MA |
| Primary Theme and Topics |
J. Disorders of the Nervous System and Aging - 146. Drugs of abuse: opioids and others |
| Secondary Theme and Topics | I. Neural Basis of Behavior<br />- 120. Behavioral pharmacology |
| Session: |
773. Drugs of abuse: miscellaneous compounds Poster |
| Presentation Time: | Wednesday, November 8, 2000 4:00 PM-5:00 PM |
| Location: | Hall G-J |
| Keywords: | THC, PET, temporal, auditory |
Whether chronic marijuana (MJ) use adversely affects human brain function remains controversial. Using [15O] water PET, regional cerebral blood flow during selective attention was compared in R-handed MJ users (9 M, 9 F; mean ± SD age, 22.3 ± 2.2 y) and controls (6 M, 7 F; 22.6 ± 1.9 y). The users had been using MJ ≥7 times weekly on average for ≥2 y (mean, 3.9 ± 1.8 y). The controls had never or rarely used MJ. Following MRI, and after ≥26 h of monitored abstention, subjects performed dichotic listening tests using nonsense word stimuli while being imaged with PET. The tests were modifications of previous ones used by our group (O'Leary et al. (1996) Brain Lang 53: 20-39). During separate tests, attention was directed to the L and R ears. A control test, choice reaction time (missing for 2 subjects), was used to control for auditory stimulation and motor responses. Within group subtractions of the control test from the attention tests showed major attention-related activations in auditory cortex, i.e., superior temporal gyrus/Heschl's gyrus. Controls showed greater volumes of activation on the side opposite to the attended ear for both L (voxels = 5246 contralateral vs. 2801 ipsilateral) and R (5998 vs. 858) ears. Corresponding volumes for MJ users (3926 vs. 5127 for L ear; 6643 vs. 2931 for R ear) showed greater L than R hemisphere activation for both ears. Chronic MJ use apparently alters the normal, ear-dependent pattern of hemispheric asymmetry.
Supported by DA10554 from NIDA-NIH and RR00059 from NCRR-NIH
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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