title: Prefrontal cortex activity during motor tasks with additional mental load requiring attentional demand: a near-infrared spectroscopy study.
abstract: Functional near-infrared spectroscopy (fNIRS) is suitable for investigating cerebral oxygenation changes during motor and/or mental tasks. In the present study, we investigated how an additional mental load during a motor task at two submaximal loadings affects the fNIRS-measured brain activation over the right prefrontal cortex (PFC). Fifteen healthy males performed isometric grasping contractions at 15% and 30% of the maximal voluntary contraction (MVC) with or without an additional mental (i.e., arithmetic) task. Mental performance, force variability, fNIRS and subjective perception responses were measured in each condition. The performance of the mental task decreased significantly while the force variability increased significantly at 30% MVC as compared to 15% MVC, suggesting that performance of dual-task required more attentional resources. PFC activity increased significantly as the effort increased from 15% to 30% MVC (p<.001). Although a larger change in the deoxyhemoglobin was observed in dual-task conditions (p=.051), PFC activity did not change significantly as compared to the motor tasks alone. In summary, participants were unable to invest more attention and effort in performing the more difficult levels in order to maintain adequate mental performance.
authors.affiliation: Movement to Health M2H, Montpellier-1 University, EuroMov, 700 Avenue du Pic Saint Loup, 34090 Montpellier, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Mandrick
authors.forename: Gérard
authors.initials: G
authors.lastname: Derosiere
authors.forename: Gérard
authors.initials: G
authors.lastname: Dray
authors.forename: Denis
authors.initials: D
authors.lastname: Coulon
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Micallef
authors.forename: Stéphane
authors.initials: S
authors.lastname: Perrey
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D018737:Hand Strength; D006801:Humans; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared