Pharmacological modulation of behavioral and neuronal correlates of repetition priming.
In this experiment we address the pharmacological modulation of repetition priming, a basic form of learning, using event-related functional magnetic resonance imaging. We measured brain activity in a word-stem completion paradigm in which, before study, volunteers were given either placebo, lorazepam (2 mg orally), or scopolamine (0.4 mg, i.v.). Relative to placebo, both drugs attenuated the behavioral expression of priming. Repetition was associated with a decreased neuronal response in left extrastriate, left middle frontal, and left inferior frontal cortices in the placebo group. Both drugs abolished these "repetition suppression" effects. By showing a concurrence of behavioral and neuronal modulations, the results suggest that GABAergic and cholinergic systems influence the neuronal plasticity necessary for repetition priming.
Thiel
C M
CM
Wellcome Department of Cognitive Neurology, Institute of Neurology, London, WC1 3BG, United Kingdom. cthiel@fil.ion.ucl.ac.uk
Henson
R N
RN
Morris
J S
JS
Friston
K J
KJ
Dolan
R J
RJ
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D001931:Brain Mapping; D004311:Double-Blind Method; D004333:Drug Administration Routes; D004334:Drug Administration Schedule; D005260:Female; D018757:GABA Modulators / Q000494:pharmacology; D006801:Humans; D007858:Learning / Q000187:drug effects* / Q000502:physiology; D008140:Lorazepam / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011932:Reading; D012601:Scopolamine / Q000494:pharmacology*; D014705:Verbal Behavior / Q000187:drug effects* / Q000502:physiology; D014936:Word Association Tests
D018757:GABA Modulators; D018727:Muscarinic Antagonists; D012601:Scopolamine; D008140:Lorazepam