title: Improvement in precision grip force control with self-modulation of primary motor cortex during motor imagery.
abstract: Motor imagery (MI) has shown effectiveness in enhancing motor performance. This may be due to the common neural mechanisms underlying MI and motor execution (ME). The main region of the ME network, the primary motor cortex (M1), has been consistently linked to motor performance. However, the activation of M1 during motor imagery is controversial, which may account for inconsistent rehabilitation therapy outcomes using MI. Here, we examined the relationship between contralateral M1 (cM1) activation during MI and changes in sensorimotor performance. To aid cM1 activity modulation during MI, we used real-time fMRI neurofeedback-guided MI based on cM1 hand area blood oxygen level dependent (BOLD) signal in healthy subjects, performing kinesthetic MI of pinching. We used multiple regression analysis to examine the correlation between cM1 BOLD signal and changes in motor performance during an isometric pinching task of those subjects who were able to activate cM1 during motor imagery. Activities in premotor and parietal regions were used as covariates. We found that cM1 activity was positively correlated to improvements in accuracy as well as overall performance improvements, whereas other regions in the sensorimotor network were not. The association between cM1 activation during MI with performance changes indicates that subjects with stronger cM1 activation during MI may benefit more from MI training, with implications toward targeted neurotherapy.
authors.affiliation: Rehabilitation Engineering Laboratory, Eidgenössische Technische Hochschule Zürich Zurich, Switzerland ; Chair in Non-Invasive Brain-Machine Interface, Center for Neuroprosthetics, École polytechnique fédérale de Lausanne Lausanne, Switzerland.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Blefari
authors.affiliation: Rehabilitation Engineering Laboratory, Eidgenössische Technische Hochschule Zürich Zurich, Switzerland ; Department of Mechanical Engineering, University of Texas at Austin Austin, TX, USA.
authors.forename: James
authors.initials: J
authors.lastname: Sulzer
authors.affiliation: Institute of Neuroinformatics, University of Zurich and Eidgenössische Technische Hochschule Zürich Zurich, Switzerland.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Hepp-Reymond
authors.affiliation: Neuroradiology Clinic, University Hospital Zurich Zurich, Switzerland.
authors.forename: Spyros
authors.initials: S
authors.lastname: Kollias
authors.affiliation: Rehabilitation Engineering Laboratory, Eidgenössische Technische Hochschule Zürich Zurich, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Gassert
keywords: motor imagery; motor skill; neurofeedback; real-time fMRI