title: Trunk rotation affects temporal order judgments with direct saccades: Influence of handedness.
abstract: Manipulation of the trunk midline has been shown to improve visuospatial performance in patients with unilateral visual neglect. The goal of the present study was to disentangle motor and perceptual components of egocentric midline manipulations and to investigate the contribution of individual hand preference. Two versions of visual temporal order judgment (TOJ) tasks were tested in healthy right- and left-handed subjects while trunk rotation was varied. In the congruent version, subjects were required to execute a saccade to the first of two horizontal stimuli presented with different stimulus onset asynchronies (SOA). In the incongruent version, subjects were required to perform a vertical saccade to a pre-learned color target, thereby dissociating motor response from the perceptual stimulus location. The main findings of this study are a trunk rotation and response direction specific impact on temporal judgments in form of a prior entry bias for right hemifield stimuli during rightward trunk rotation, but only in the congruent task. This trunk rotation-induced spatial bias was most pronounced in left-handed participants but had the same sign in the right-handed group. Results suggest that egocentric midline shifts in healthy subjects induce a spatially-specific motor, but not a perceptual, bias and underline the importance of taking individual differences in functional laterality such as handedness and mode of perceptual report into account when evaluating effects of trunk rotation in either healthy subjects or neurological patients.
authors.affiliation: Department of Cognitive Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; Department of Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany; Department of Child and Adolescent Psychiatry, University Medicine Goettingen, von-Siebold-Str. 5, 37075 Goettingen, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Paschke
authors.affiliation: Department of Cognitive Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Goettingen, Germany.
authors.forename: Igor
authors.initials: I
authors.lastname: Kagan
authors.affiliation: Department of Psychiatry and Psychotherapy, Charité-University Medicine Berlin, Campus Mitte, Charitéplatz 1, 10117 Berlin, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Wüstenberg
authors.affiliation: Department of Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Bähr
authors.affiliation: Department of Cognitive Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Goettingen, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Germany. Electronic address: melanie.wilke@med.uni-goettingen.de.
authors.forename: Melanie
authors.initials: M
authors.lastname: Wilke
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007600:Judgment; D008297:Male; D009949:Orientation / Q000502:physiology*; D011930:Reaction Time; D012399:Rotation; D012438:Saccades / Q000502:physiology*; D013997:Time Factors; D060726:Torso / Q000294:innervation; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Handedness; Laterality; Ocular dominance; Reference frames; Spatial neglect; Temporal order judgment; Trunk rotation