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The P3b versus the P3a : an event related potential investigation of the glucose facilitation effect.

Research output: Contribution to journalJournal article


<mark>Journal publication date</mark>07/2008
<mark>Journal</mark>Journal of Psychopharmacology
Issue number5
Number of pages7
Pages (from-to)486-492
<mark>Original language</mark>English


The ingestion of a glucose containing drink has been shown to improve performance on a variety of cognitive tasks. There is debate, however, as to whether glucose especially benefits hippocampal memory functioning or whether it has a more global effect on attentional systems. The present study used event related potential methodology (ERPs) to investigate further glucose-mediated cognitive processes. Each participant acted as his/her own control in a repeated measures design, receiving one of two possible treatments (25g glucose vs. placebo) in a counterbalanced order. After a two hour fasting period participants completed a visual three-stimulus oddball task. This paradigm involves an individual detecting an infrequent target stimulus randomly embedded in a train of repetitive background or standard stimuli. Detection of the target results in a large P3b ERP component (memory updating effect). The infrequent presentation of a novel and irrelevant stimulus, randomly interspersed with the target and standard stimuli, generates a P3a response (orientation of attention effect). These components were used as markers to establish whether the glucose enhancement effect was restricted to the neuro-cognitive processes related to memory. Consistent with behavioural work, glucose moderated the magnitude and latency of the P3b ERP component. However, glucose also interacted with attentional systems (P3a and an earlier P2), although this effect was non-significant. This work converges with recent fMRI findings indicating the sensitivity of the medial-temporal lobes and the pre-frontal cortex to glucose administration.

Bibliographic note

“The final, definitive version of this article has been published in the Journal, Journal of Psychopharmacology, 22 (5), 2008, © SAGE Publications Ltd, 2008 by SAGE Publications Ltd at the Journal of Psychopharmacology page: http://jop.sagepub.com/ on SAGE Journals Online: http://online.sagepub.com/