Eye movements in cocaine abusers.
Using electro-oculography, we quantitatively investigated eye movements in nine heavy cocaine abusers and three groups of controls. Plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG), a major metabolite of brain norepinephrine, in cocaine abusers were reduced to an average of 53% of normal. Cocaine abusers had normal smooth pursuit, optokinetic nystagmus, vestibulo-ocular reflex, visual suppression of the vestibulo-ocular reflex, and caloric nystagmus. Data were suggestive of a significant reduction in the degree of immediate enhancement of visual-vestibulo-ocular reflex gain by magnified vision in the cocaine abusers. However, adaptive plasticity of the vestibulo-ocular reflex was normal in the cocaine abusers. These results suggest that, despite animal data linking vestibulo-ocular reflex plasticity to central norepinephrine, this neurotransmitter may not be important to plasticity in human beings.
Demer
J L
JL
Jules Stein Eye Institute, University of California, Los Angeles 90024-1771.
Volkow
N D
ND
Ulrich
I
I
Krajewski
K
K
Davis
C M
CM
Porter
F I
FI
D000328:Adult; D002150:Caloric Tests; D003042:Cocaine; D005133:Eye Movements / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000097:blood; D009760:Nystagmus, Physiologic / Q000187:drug effects; D011567:Psychiatric Department, Hospital; D011698:Pursuit, Smooth / Q000187:drug effects; D012027:Reflex, Vestibulo-Ocular / Q000187:drug effects; D012438:Saccades / Q000187:drug effects; D019966:Substance-Related Disorders / Q000175:diagnosis* / Q000534:rehabilitation
D008734:Methoxyhydroxyphenylglycol; D003042:Cocaine