Objective: In this study we used functional magnetic resonance imaging (fMRI) to investigate whether motor imagery (MI) of handwriting and circle drawing activates a similar cerebral motor network as actually executed writing and drawing.

Background: The concept of MI describes the imaginary execution of a movement without actual muscular activity. Previous studies have shown that MI activates a similar cerebral motor network as the execution of the same movement. This has been demonstrated for a variety of different tasks and motions. However, the neural handwriting network which has been extensively described by previous authors, lacks evidence of having an equal MI-network, so far. In addition, we assessed the comparison between writing and a highly automated task, namely drawing circles.

Method: 18 healthy right-handed participants were instructed to write the German word “Wellen” and to continuously draw circles on a specialized tablet able to capture kinematic handwriting parameters such as velocity, pressure and regularity of hand movements. Outside of the MRI-scanner, those tasks were performed in a seated and in a lying position to assess the impact of body position. Afterwards, the participants performed the same tasks, writing and circle-drawing, during fMRI, both internally, applying the principles of MI, and overtly, performing the tasks as they did outside of the scanner.

Results: The kinematic analysis revealed a general correlation of handwriting parameters during sitting and lying except for pen pressure during drawing. Writing compared to imagined writing was accompanied by an increased activity of the ipsilateral cerebellum and the contralateral sensorimotor cortex. Executed compared to imagined drawing revealed elevated activity of a fronto–parieto-temporal network. Contrasting writing and drawing directly, executed writing induced an enhanced activation of the left somatosensory and premotor area. Comparing the MI of these tasks revealed a higher involvement of occipital activation during imagined writing.

Conclusion: The kinematic results pointed to a high comparability of writing during MRI and everyday writing. Overall, we observed highly overlapping cortical activity except for a higher involvement of motor control areas during motor execution. The sparse difference between writing and drawing can be explained by highly automatized writing in healthy individuals.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/neural-correlates-of-executed-compared-to-imagined-writing-and-drawing-movements-an-fmri-study/