Abstract:
:Functional magnetic resonance imaging (fMRI) was conducted to observe the effects of cocaine administration on the physiological fluctuations of fMRI signal in two brain regions. Seven long-term cocaine users with an average age of 32 years and 8 years of cocaine use history were recruited for the study. A T2*-weighted fast echo-planar imaging (EPI) pulse sequence was employed at 1.5 T to acquire three sets of brain images for each subject under three conditions (at rest, after saline injection, and after cocaine injection [0.57 mg/kg]). Cross-correlation maps were constructed using the synchronous, low frequency signal from voxel time courses after filtering respiratory, cardiac, and other physiological noise. A quantitative evaluation of the changes in functional connectivity was made using spatial correlation coefficient (SCC) analysis. A marked 50% reduction in SCC values in the region of primary visual cortex and 43% reduction in SCC values in the region of primary motor cortex were observed after cocaine administration. This significant reduction in SCC values in these cortical regions is a reflection of changes in neuronal activity. It is suggested that the observed changes in low frequency components after acute cocaine administration during a resting, no-task situation may be used as a baseline reference source when assessing the effects of cocaine on task-driven activation or on mesolimbic dopamine pathways.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Li SJ,Biswal B,Li Z,Risinger R,Rainey C,Cho JK,Salmeron BJ,Stein EAdoi
10.1002/(sici)1522-2594(200001)43:1<45::aid-mrm6>3subject
Has Abstractpub_date
2000-01-01 00:00:00pages
45-51issue
1eissn
0740-3194issn
1522-2594pii
10.1002/(SICI)1522-2594(200001)43:1<45::AID-MRM6>3journal_volume
43pub_type
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