Neuroscience 2000 Abstract
| Presentation Number: | 493.2 |
|---|---|
| Abstract Title: | Effect of <I>d</I>-amphetamine on response to red and blue light in primary visual cortex of humans: a BOLD fMRI study. |
| Authors: |
Cowan, R. L.*1
; deB. Frederick, B.1
; Rohan, M. L.1
; Bang, J.1
; Levin, J. M.1
; Lukas, S. E.1
; Renshaw, P. F.1
1Brain Imaging Center, McLean Hospital and Department of Psychiatry, Harvard Medical School, Belmont, MA |
| Primary Theme and Topics |
J. Disorders of the Nervous System and Aging - 144. Drugs of abuse: amphetamines |
| Secondary Theme and Topics | I. Neural Basis of Behavior<br />- 118. Monoamines and behavior |
| Session: |
493. Drugs of abuse: amphetamines--general Slide |
| Presentation Time: | Tuesday, November 7, 2000 1:15 PM-1:30 PM |
| Location: | Conference Auditorium A |
| Keywords: | Drug Abuse, Addiction, Dopamine, Psychostimulant |
Reduced blue-cone electroretinograms in cocaine-withdrawn subjects correlate with the degree of cocaine craving, suggesting that altered blue cone function might serve as a marker for central nervous system dopaminergic neurotransmitter function. As numerous investigators have applied the blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) method to study stimulus-induced visual cortical activation, we chose to compare the primary visual cortical (V1) BOLD response to red and blue light during altered dopamine activity. Five healthy subjects ingested 2.5 mg oral d-amphetamine and then underwent functional magnetic resonance imaging during retinal stimulation with alternating trials of flashing red or blue light for approximately 50 minutes. Functional images were motion-corrected, and regions in right and left V1 were analyzed by comparing mean BOLD signal of pixels significantly correlated with photic stimulation. A two-sample t-test of averaged right and left V1 BOLD signal revealed mean photic stimulation-induced BOLD signal change across all trials was greater for blue (1.23%±0.41%), than for red (0.91%±0.29%) light. Linear regression modeling revealed a significant effect of trial number (presumed to correlate with rising plasma drug level) on BOLD signal increase to red (Z=3.15, p=0.002), but not blue (Z=0.242, p=0.809) light. These preliminary results suggest that amphetamine augments V1 BOLD signal change in response to red, but not blue light. Amphetamine has dose-dependent actions on both hemodynamic and neurotransmitter function, and may initially inhibit (via nonvesicular dopamine release acting at autoreceptors) and then augment (via reuptake inhibition) synaptic dopamine transmission in parallel with rising drug levels. Additional studies using higher doses of amphetamine across a range of stimulus intensities will be required to further clarify this effect.
Supported by DARSPP to R.L. Cowan, DA09448 to P.F. Renshaw and DA00343 to S.E. Lukas.
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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