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Modafinil And D-Amphetamine Action On Electroencephalogram
A DGReview of :"Distinctive effects of modafinil and d-amphetamine on the homeostatic and circadian modulation of the human waking EEG"
Psychopharmacology
03/21/2003
By Robert Short
The alertness-promoting effects of modafinil and d-amphetamine involve distinct electroencephalogram activities.
This is one conclusion resulting from a double-blind, placebo-controlled parallel design study led by Dr Florian Chapotot of the Département des Facteurs Humain, Centre de Recherches du Service de Santé des Armées, La Tronche Cedex, France.
Thirty three healthy subjects were investigated during 60 hours of sustained wakefulness. The objective of the study was to determine whether modafinil (300 mg), in comparison to the d-amphetamine (20mg) reference psychostimulant and to placebo, interferes with the vigilance regulatory processes reflected in the EEG during waking.
It was found that one hour after ingestion, both the psychostimulants increased alertness during 10 to 12 hours, independently of the time of administration. At the level of the waking EEG, d-amphetamine attenuated the natural circadian rhythm of the different frequency bands and suppressed the sleep deprivation-related increase in low frequency powers.
In contrast, modafinil had slight effect on circadian rhythms. Its selective action was characterized by maintenance of the alpha1 EEG power, which under placebo exhibited a homeostatic decrease paralleling that of alertness with a circadian trough at night.
The researchers said, "These findings demonstrate that the alertness-promoting effects of modafinil and d-amphetamine involve distinct EEG activities and do not reside on the same vigilance regulatory processes. While d-amphetamine inhibits the expression of a sleep-related process, probably through a direct cortical activation masking EEG circadian rhythms, modafinil, through a synchronic effect , preferentially disrupts the homeostatic down-regulation of a waking drive."
Psychopharmacology 2003;166:127-138.
"Distinctive effects of modafinil and d-amphetamine on the homeostatic and circadian modulation of the human waking EEG"
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