title: Dynamic changes in brain functional connectivity during concurrent dual-task performance.
abstract: This study investigated the spatial, spectral, temporal and functional proprieties of functional brain connections involved in the concurrent execution of unrelated visual perception and working memory tasks. Electroencephalography data was analysed using a novel data-driven approach assessing source coherence at the whole-brain level. Three connections in the beta-band (18-24 Hz) and one in the gamma-band (30-40 Hz) were modulated by dual-task performance. Beta-coherence increased within two dorsofrontal-occipital connections in dual-task conditions compared to the single-task condition, with the highest coherence seen during low working memory load trials. In contrast, beta-coherence in a prefrontal-occipital functional connection and gamma-coherence in an inferior frontal-occipitoparietal connection was not affected by the addition of the second task and only showed elevated coherence under high working memory load. Analysis of coherence as a function of time suggested that the dorsofrontal-occipital beta-connections were relevant to working memory maintenance, while the prefrontal-occipital beta-connection and the inferior frontal-occipitoparietal gamma-connection were involved in top-down control of concurrent visual processing. The fact that increased coherence in the gamma-connection, from low to high working memory load, was negatively correlated with faster reaction time on the perception task supports this interpretation. Together, these results demonstrate that dual-task demands trigger non-linear changes in functional interactions between frontal-executive and occipitoparietal-perceptual cortices.
authors.affiliation: Melbourne Neuropsychiatry Centre, The University of Melbourne, Melbourne, Australia. l.cocchi@uq.edu.au
authors.forename: Luca
authors.initials: L
authors.lastname: Cocchi
authors.forename: Andrew
authors.initials: A
authors.lastname: Zalesky
authors.forename: Ulrike
authors.initials: U
authors.lastname: Toepel
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Whitford
authors.forename: Marzia
authors.initials: M
authors.lastname: De-Lucia
authors.forename: Micah M
authors.initials: MM
authors.lastname: Murray
authors.forename: Olivia
authors.initials: O
authors.lastname: Carter
mesh_terms: D000328:Adult; D001519:Behavior / Q000502:physiology; D001921:Brain / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D013647:Task Performance and Analysis; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology