title: Coordinated flexibility: how initial gaze position modulates eye-hand coordination and reaching.
abstract: Reaching to targets in space requires the coordination of eye and hand movements. In two experiments, we recorded eye and hand kinematics to examine the role of gaze position at target onset on eye-hand coordination and reaching performance. Experiment 1 showed that with eyes and hand aligned on the same peripheral start location, time lags between eye and hand onsets were small and initiation times were substantially correlated, suggesting simultaneous control and tight eye-hand coupling. With eyes and hand departing from different start locations (gaze aligned with the center of the range of possible target positions), time lags between eye and hand onsets were large and initiation times were largely uncorrelated, suggesting independent control and decoupling of eye and hand movements. Furthermore, initial gaze position strongly mediated manual reaching performance indexed by increments in movement time as a function of target distance. Experiment 2 confirmed the impact of target foveation in modulating the effect of target distance on movement time. Our findings reveal the operation of an overarching, flexible neural control system that tunes the operation and cooperation of saccadic and manual control systems depending on where the eyes look at target onset.
authors.affiliation: Faculty of Health, Medicine and Life Sciences, School of Mental Health and Neurosciences, Maastricht University Medical Centre, Universiteitssingel 50, 6229 ER, Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands. jos.adam@maastrichtuniversity.nl
authors.forename: Jos J
authors.initials: JJ
authors.lastname: Adam
authors.forename: Simona
authors.initials: S
authors.lastname: Buetti
authors.forename: Dirk
authors.initials: D
authors.lastname: Kerzel
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D053483:Eye Movement Measurements / Q000295:instrumentation / Q000523:psychology; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012438:Saccades / Q000502:physiology; D013997:Time Factors; D055815:Young Adult