Titre du document / Document title

Processing efficiency of a verbal working memory system is modulated by amphetamine : an fMRI investigation

Auteur(s) / Author(s)

TIPPER Christine M. ⁽¹⁾ ; CAIRO Tara A. ⁽²⁾ ; WOODWARD Todd S. ⁽³⁾ ; PHILLIPS Anthony G. ⁽²⁾ ; LIDDLE Peter F. ⁽⁴⁾ ; NGAN Elton T. C. ⁽²⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, V6T 1Z4, CANADA
⁽²⁾ Department of Psychiatry, University of British Columbia, Vancouver, CANADA
⁽³⁾ Department of Research, Riverview Hospital, Coquitlam, CANADA
⁽⁴⁾ Division of Psychiatry, Queens Medical Centre, Nottingham, ROYAUME-UNI

Résumé / Abstract

Rationale: Working memory performance may be improved or decreased by amphetamine, depending on baseline working memory capacity and amphetamine dosage. This variable effect suggests an optimal range of monaminergic activity for working memory, either below or above which it is compromised. We directly tested this possibility with human participants by varying amphetamine dosage and measuring the efficiency of cortical processing in brain regions associated with working memory. Objectives: The modulation of cortical processing in a verbal working memory network by dextroamphetamine (D-amph) was examined using BOLD functional magnetic resonance imaging (fMRI) with healthy participants. The goal of the study was to test the hypothesis of an inverted U-shaped relationship between D-amph dose and processing efficiency of a verbal working memory system. Methods: D-amph dosage was increased cumulatively every 2 h across four scanning sessions collected in a single day. The primary measure used for analyses in this study was the extent of activation in brain regions empirically defined as a working memory network. Results: An inverted U-shaped relationship was observed between the amount of D-amph administered and working memory processing efficiency. This relationship was specific to brain areas functionally defined as working memory regions and to the encoding/maintenance phase (as opposed to the response phase) of the task. Conclusion: The results are consistent with the hypothesis that the neurochemical effects of amphetamine modulate the efficiency of a verbal working memory system. The effect of amphetamine on working memory in healthy individuals may provide insight regarding the working memory deficits seen in schizophrenia, given the overlap between neurochemical systems affected by amphetamine, and those disordered in schizophrenia.

Revue / Journal Title

Psychopharmacologia   ISSN 0033-3158   CODEN PSYPAG 

Source / Source

2005, vol. 180, n^o 4 (213 p.)  [Document : 10 p.] (1 p.1/4), pp. 634-643 [10 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Springer, Berlin, ALLEMAGNE  (1959) (Revue)

Mots-clés anglais / English Keywords

Catecholamine ; Neurotransmitter ; Amphetamine derivatives ; Psychotropic ; CNS stimulant ; Cognition ; Dose activity relation ; Human ; Dopaminergic pathway ; Dopamine ; Amfetamine ; Information processing ; Functional analysis ; Nuclear magnetic resonance imaging ; Verbal memory ;

Mots-clés français / French Keywords

Catécholamine ; Neurotransmetteur ; Amphétamine dérivé ; Psychotrope ; Stimulant SNC ; Cognition ; Relation dose réponse ; Homme ; Voie dopaminergique ; Dopamine ; Amfétamine ; Traitement information ; Analyse fonctionnelle ; Imagerie RMN ; Mémoire verbale ;

Mots-clés espagnols / Spanish Keywords

Catecolamina ; Neurotransmisor ; Amfetamina derivado ; Psicotropo ; Estimulante SNC ; Cognición ; Relación dosis respuesta ; Hombre ; Vía dopaminérgica ; Dopamina ; Anfetamina ; Procesamiento información ; Análisis funcional ; Imaginería RMN ; Memoria verbal ;

Mots-clés d'auteur / Author Keywords

Amphetamine ; Working memory ; fMRI ; Dose-response relationship ; Monoamines ; Dopamine ; Schizophrenia ; Cognition ;

Localisation / Location

INIST-CNRS, Cote INIST : 1761, 35400013154159.0060