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dc.contributor.authorMoran, Rosalynen
dc.contributor.authorCampo, Pabloen
dc.contributor.authorMaestu, Fernandoen
dc.contributor.authorReilly, Richard B.en
dc.contributor.authorDolan, Raymond J.en
dc.contributor.authorStrangle, Bryan A.en
dc.description.abstractTheta oscillations in the local field potential of neural ensembles are considered key mediators of human working memory. Theoretical accounts arising from animal hippocampal recordings propose that the phase of theta oscillations serves to instantiate sequential neuronal firing to form discrete representations of items held online. Human evidence of phase relationships in visual working memory has enhanced this theory, implicating long theta cycles in supporting greater memory capacity. Here we use human magnetoencephalographic recordings to examine a novel, alternative principle of theta functionality. The principle we hypothesize is derived from information theory and predicts that rather than long (low frequency) theta cycles, short (high frequency) theta cycles are best suited to support high information capacity. From oscillatory activity recorded during the maintenance period of a visual working memory task we show that a network of brain regions displays an increase in peak 4–12 Hz frequency with increasing memory load. Source localization techniques reveal that this network comprises bilateral prefrontal and right parietal cortices. Further, the peak of oscillation along this theta–alpha frequency axis is significantly higher in high capacity individuals compared to low capacity individuals. Importantly while we observe the adherence of cortical neuronal oscillations to our novel principle of theta functioning, we also observe the traditional inverse effect of low frequency theta maintaining high loads, where critically this was located in medial temporal regions suggesting parallel, dissociable hippocampal-centric, and prefrontal-centric theta mechanisms.en
dc.description.sponsorshipThis work was funded by a grant from the Ministry of Science, Spain SEJ2006-14571 to Pablo Campo, and partially supported by a Grant from the Comunidad Autónoma de Madrid, Spain (Madr. IB S-SAL-0312-2006). Rosalyn J. Moran was funded by an Award from the Max Planck Society to Raymond J. Dolan; Raymond J. Dolan is supported by the Wellcome Trust.en
dc.format.extent12 pagesen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.subjectvisual working memoryen
dc.titlePeak frequency in the theta and alpha bands correlates with human working memory capacityen
dc.typeArticle - Refereeden
dc.title.serialFrontiers in Human Neuroscienceen

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Creative Commons Attribution 4.0 International
License: Creative Commons Attribution 4.0 International