Neuropsychologia 48 (2010) 2517–2527 Contents lists available at ScienceDirect Neuropsychologia journal homepage: www.elsevier.com/locate/neuropsychologia Dual-task interference during initial learning of a new motor task results from competition for the same brain areas Florence Rémy a,b,c,∗ , Nicole Wenderoth a , Karen Lipkens a , Stephan P. Swinnen a a Research Center for Movement Control and Neuroplasticity, Department of Biomedical Kinesiology, Group Biomedical Sciences, Katholieke Universiteit Leuven, 3001 Heverlee, Belgium b Université de Toulouse, UPS, Centre de Recherche Cerveau et Cognition, France c CNRS, CerCo, Toulouse, France article info Article history: Received 18 September 2009 Received in revised form 15 March 2010 Accepted 22 April 2010 Available online 29 April 2010 Keywords: Motor learning fMRI Dual task Bimanual Coordination abstract Cerebral patterns of activity elicited by dual-task performance throughout the learning of a complex bimanual coordination pattern were addressed. Subjects (N = 12) were trained on the coordination pattern and scanned using fMRI at early (PRE) and late (POST) learning stages. During scanning, the coordination pattern was performed either as a single task or in concurrence with a simultaneous visual search task (i.e. dual task). Kinematics data revealed a significant performance improvement as a result of learning. In PRE-scanning, the dual-task condition induced deterioration of motor performance, relative to the single-task condition. Activity in lateral frontal and parietal regions involved in both visual search and motor coordination tasks (i.e. ‘overlapping’ regions) was reduced when the tasks were performed simultaneously. In POST-scanning, kinematics performance was equivalent under single- and dual-task conditions, suggesting automaticity of the coordination pattern. Furthermore, overlap between regions involved in visual search and motor tasks was reduced, and dual-task performance was no longer asso- ciated with reduction of frontal and parietal activity. Our results suggest that behavioral interference between a complex motor coordination task and a simple simultaneous visual search task occurs when both tasks recruit overlapping regions in the frontal and parietal cortices. This may provide a neural basis for dissipation of dual-task interference following extensive motor practice, which is a traditional behavioral marker of motor automaticity. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction The continuous practice of a new motor skill results in pro- gressive improvement of performance. During the initial learning phase, performance increases rapidly and attentional demands are high, whereas in an advanced (automatization) phase, a perfor- mance plateau is reached and attention is diminished (Fitts & Posner, 1967; Magill, 2007; Nissen & Bullemer, 1987; Schmidt & Lee, 1999). This increasing level of automaticity has been tested in behavioral studies using dual-task paradigms. When the motor task is performed at the same time as another task, interference between both tasks is high in early learning, resulting in deterioration of motor performance. Once the motor task has been overlearned, interference is low or inexistent, indicating high automaticity (Eversheim & Bock, 2001; Passingham, 1996; Temprado, Monno, ∗ Corresponding author at: Université Paul Sabatier, Centre de Recherche Cerveau et Cognition, Faculté de Médecine de Rangueil, 133 Route de Narbonne, 31062 Toulouse Cedex 9, France. Tel.: +33 5 62 17 28 06; fax: +33 5 62 17 28 09. E-mail address: florence.remy@cerco.ups-tlse.fr (F. Rémy). Zanone, & Kelso, 2002; Wu, Kansaku, & Hallett, 2004). Although the latter observations are considered a hallmark in behavioral studies, the neural correlates underlying dual-task interference in early motor learning, as well as its dissipation with further motor practice, have not been previously examined using imaging techniques. In the present functional magnetic resonance imag- ing (fMRI) study, young healthy subjects were extensively trained on a complex bimanual coordination pattern, and scanned in early and late phases of practice. During scanning sessions, subjects per- formed the motor pattern in both single- and dual-task conditions. The study was therefore designed to investigate changes in cerebral patterns of activity induced by dual-task performance, throughout motor learning. These changes in activity were looked at in relation to changes in behavioral performance. Neural correlates of dual-task completion have been previously examined in imaging studies. Several authors have argued that dual-task interference, i.e. decrease of performance in one of the tasks or both, may arise when simultaneous tasks recruit over- lapping cortical fields, in the frontal and parietal lobes (Klingberg, 1998; Klingberg & Roland, 1997; Passingham, 1996; Roland & Zilles, 1998; Wu et al., 2004). According to this hypothesis, interference 0028-3932/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.neuropsychologia.2010.04.026