Non-magnetic equipment for the high-resolution quantification of finger kinematics during functional studies of bimanual coordination

Simultaneous recording of behavioral and functional data is crucial in capturing the neural mechanisms underpinning human motor actions. We describe a non-magnetic equipment (NME) to record finger kinematics, in particular the absolute amplitude of finger oscillation, during bimanual coordination paradigms performed in functional studies. NME monitors finger movements with optic fiber signals that are post-processed off-line to quantify finger kinematics. A phantom experiment demonstrated no mutual interference between NME and fMRI, hence the usability of NME in environments sensitive to electro-magnetic fields. The spatial and temporal resolutions of NME data (1 mm and 1 ms), its reliability and feasibility when studying human subjects were verified with two comparative experiments performed with NME and a validated infrared camera (IRC) system. Results showed that the restrictions of NME (reduction of degrees of freedom of the coordinated system and potential haptic feedback) do not interfere with the correct reconstruction of finger kinematics. We also demonstrated that the recorded behavioral information can be used to detect neural activity associated with specific features of coordinated behavior. Therefore, we believe that the use of NME for the combined analysis of behavioral and functional data may help assessing an adequate interpretation of the cortical activity associated with specific tasks. This approach might as well help to explore the role of specific brain areas in motor processes, with a potential great impact in the diagnosis and subsequent intervention in brain injured patients, or in children affected by developmental coordination disorders.