title: Relationship between sustained unilateral hand clench, emotional state, line bisection performance, and prefrontal cortical activity: A functional near-infrared spectroscopy study.
abstract: Sustained unilateral hand clenching alters perceptual processing and affective/motivational state, with these alterations presumed to reflect increased hemispheric activity contralateral to the side of motor movement. However, data from electroencephalographic and imaging studies are contradictory regarding the relationship between sustained hand clenching and brain activity. In order to investigate the relationship between brain activity, sustained unilateral hand clenching, and changes in affect and perceptual processing, frontal hemispheric activity was measured via functional near-infrared spectroscopy (fNIRS), using derived O2Hb prior to, during, and post-sustained unilateral hand clench. Participants' mood and spatial perception were recorded pre- and post-clenching. Sustained unilateral hand clenching altered brain activity and mood, but not spatial perception. Results revealed increased O2Hb bilaterally following sustained unilateral hand clenching, relative to baseline, regardless of hand. In agreement with previous fNIRS studies, sustained unilateral hand clenching resulted in greater ipsilateral, compared with contralateral, O2Hb. An interaction between side of hand clench and change in mood was in the direction predicted by theories of hemispheric lateralization of emotion: Following left-hand clenching, individuals became more affectively negative, and following right-hand clenching, they became more affectively positive.
authors.affiliation: a Psychology Department , Montclair State University , Montclair , NJ , USA.
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Propper
authors.affiliation: a Psychology Department , Montclair State University , Montclair , NJ , USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Dodd
authors.affiliation: b Psychology Department , University of Toledo , Toledo , OH , USA.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Christman
authors.affiliation: c Psychology Department , Tufts University , Medford , MA , USA.|d US Army Natick Soldier Research, Development and Engineering Center , Natick , MA , USA.
authors.forename: Tad T
authors.initials: TT
authors.lastname: Brunyé
mesh_terms: D001921:Brain / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D007839:Functional Laterality; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D009483:Neuropsychological Tests; D010108:Oxyhemoglobins / Q000378:metabolism; D019265:Spectroscopy, Near-Infrared
chemical_list: D010108:Oxyhemoglobins
keywords: emotion; fNIRS; frontal cortex; hand clench