Original Research Article
Bimanual passive movement: functional activation and inter-regional coupling
1 Neuroimaging Laboratory, Santa Lucia Foundation, Italy
2 Radiology Department, Santa Lucia Foundation, Italy
2 Radiology Department, Santa Lucia Foundation, Italy
The aim of this study was to investigate intra-regional activation and inter-regional connectivity during passive movement. During fMRI, a mechanic device was used to move the subject’s index and middle fingers. We assessed four movement conditions (unimanual left/right, bimanual symmetric/asymmetric), plus Rest. A conventional intra-regional analysis identified the passive stimulation network, including motor cortex, primary and secondary somatosensory cortex, plus the cerebellum. The posterior (sensory) part of the sensory–motor activation around the central sulcus showed a significant modulation according to the symmetry of the bimanual movement, with greater activation for asymmetric compared to symmetric movements. A second set of fMRI analyses assessed condition-dependent changes of coupling between sensory–motor regions around the superior central sulcus and the rest of the brain. These analyses showed a high inter-regional covariation within the entire network activated by passive movement. However, the specific experimental conditions modulated these patterns of connectivity. Highest coupling was observed during the Rest condition, and the coupling between homologous sensory–motor regions around the left and right central sulcus was higher in bimanual than unimanual conditions. These findings demonstrate that passive movement can affect the connectivity within the sensory–motor network. We conclude that implicit detection of asymmetry during bimanual movement relies on associative somatosensory region in post-central areas, and that passive stimulation reduces the functional connectivity within the passive movement network. Our findings open the possibility to combine passive movement and inter-regional connectivity as a tool to investigate the functionality of the sensory–motor system in patients with very poor mobility.
Keywords: passive movement, bimanual, effective connectivity, fMRI
Copyright: © 2007 Macaluso, Cherubini and Sabatini. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
*Correspondence: Emiliano Macaluso, Neuroimaging Laboratory, Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy. e-mail: e.macaluso@hsantalucia.it
Citation: Macaluso E, Cherubini A and Sabatini U (2007) Bimanual passive movement: functional activation and inter-regional coupling. Front. Integr. Neurosci. (2007) 1:5. doi:10.3389/neuro.07.005.2007
Received: 30 August 2007; paper pending published: 11 October 2007; accepted: 29 November 2007; published online: 30 December 2007.
Edited by:
Sidney A. Simon, Duke University, USA
Reviewed by:
Ivan Toni, F.C. Donders Centre for Cognitive Neuroimaging, Netherlands
Sidney A. Simon, Duke University, USA
Sidney A. Simon, Duke University, USA
*Correspondence: Emiliano Macaluso, Neuroimaging Laboratory, Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy. e-mail: e.macaluso@hsantalucia.it


