Neuroscience 2005 Abstract
| Presentation Number: | 877.3 |
|---|---|
| Abstract Title: | Inhibitory function and white matter changes in chronic marijuana smokers: a DTI study. |
| Authors: |
Gruber, S. A.*1,2
; Pimentel, P.1
; Yurgelun-Todd, D. A.1,2
1Cognitive Neuroimaging Laboratory, McLean Hospital, Belmont, MA 2Dept. of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA |
| Primary Theme and Topics |
Cognition and Behavior - Human Cognition, Behavior, and Anatomy -- Reasoning and problem solving |
| Secondary Theme and Topics | Techniques in Neuroscience<br />- Staining, Tracing, and Imaging Techniques |
| Session: |
877. Reasoning and Problem Solving Poster |
| Presentation Time: | Wednesday, November 16, 2005 10:00 AM-11:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # GG30 |
| Keywords: | CANNABINOIDS, NEUROIMAGING, COGNITION, DIFFUSION |
Abnormalities in executive function and the ability to successfully monitor and inhibit inappropriate behaviors have been reported in substance abusing individuals. Recent investigations which have utilized neuroimaging and neurocognitive techniques to evaluate frontal systems in heavy cannabis smokers have reported alterations during inhibitory tasks which require frontal processing. Diffusion tensor imaging (DTI) methods provide a quantitative estimate of white matter integrity, providing new insight at the microstructural level. We applied diffusion tensor imaging techniques (DTI) and a brief neurocognitive battery which included measures of frontal/executive function to examine the relationship between frontal white matter changes and neuropsychological performance in nine heavy cannabis smokers and 9 matched control subjects. DTI data were acquired on a 3.0 Tesla scanner using a diffusion weighted twice-refocused spin echo EPI sequence. Voxels (11cm3) were placed in the midline of the splenium of the corpus callosum by a blind rater. FA was calculated from the voxels placed on axial images. Fractional anisotropy (FA), a measure of directional coherence within white matter fiber tracts was calculated bilaterally. In MJ smokers, FA of the splenium was significantly correlated with two discrete measures of inhibitory function, time to complete the Stroop interference task (p=.029) and the time difference between Trailmaking B vs A (p =.021), while no significant correlations were detected for the NC subjects. Higher FA values were associated with better performance in MJ smokers. No significant relationship was found between urinary cannabinoid concentration and FA, indicating that acute exposure to cannabis is not likely to account for the findings. These neurocognitive measures are sensitive to psychomotor function and inhibitory capacity, suggesting that MJ smokers who perform these tasks poorly may have underlying alterations in white matter fiber tracts.
Supported by NIDA DA016695
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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