Functional connectivity during motor imagery of complex bimanual everyday actions

The present study investigated the functional neuroanatomical correlates of motor imagery (MI) of complex bimanual everyday actions (also called functional tasks). For this, 17 participants underwent functional magnetic resonance imaging (fMRI) and performed MI of bimanual actions (e.g., tying shoelaces) and of unimanual actions (e.g. writing) performed with the right and left hand. While a standard univariate fMRI analysis showed no reliable cortical activations specific to bimanual MI, a subsequent functional connectivity analysis (psychophysiological interactions) showed increased connectivity during bimanual MI, as compared to unimanual MI, mainly between inter- and intrahemispheric somatosensory and premotor cortices. These results demonstrate that MI of ecologically valid everyday tasks shows a comparable pattern of functional connectivity as has been reported for MI of more simple, standardized laboratory tasks such as finger-opposition. Furthermore, the present results show for the first time that MI of bimanual actions shows a comparable pattern of functional connectivity as has been reported for overt bimanual performance, thus strongly supporting the assumed equivalence of MI and motor execution. Potential benefits of MI of bimanual everyday actions over MI of unimanual simple laboratory tasks for clinical application such as motor rehabilitation and for training of athletes and musicians are discussed. Keywords Motor imagery, bimanual, functional magnetic resonance imaging (fMRI), functional connectivity (psychophysiological interactions), functional task