title: Microstructural properties of premotor pathways predict visuomotor performance in chronic stroke.
abstract: Microstructural properties of the corticospinal tract (CST) descending from the motor cortex predict strength and motor skill in the chronic phase after stroke. Much less is known about the relation between brain microstructure and visuomotor processing after stroke. In this study, individual's poststroke and age-matched controls performed a unimanual force task separately with each hand at three levels of visual gain. We collected diffusion MRI data and used probabilistic tractography algorithms to identify the primary and premotor CSTs. Fractional anisotropy (FA) within each tract was used to predict changes in force variability across different levels of visual gain. Our observations revealed that individuals poststroke reduced force variability with an increase in visual gain, performed the force task with greater variability as compared with controls across all gain levels, and had lower FA in the primary motor and premotor CSTs. Our results also demonstrated that the CST descending from the premotor cortex, rather than the primary motor cortex, best predicted force variability. Together, these findings demonstrate that the microstructural properties of the premotor CST predict visual gain-related changes in force variability in individuals poststroke. Hum Brain Mapp 37:2039-2054, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida.
authors.forename: Derek B
authors.initials: DB
authors.lastname: Archer
authors.affiliation: Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Misra
authors.affiliation: Neural Control of Movement Lab, Department of Physical Therapy, University of Florida and Malcolm-Randall VA Medical Center, Gainesville, Florida.
authors.forename: Carolynn
authors.initials: C
authors.lastname: Patten
authors.affiliation: Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Coombes
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D056228:Feedback, Sensory / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology; D009048:Motor Skills / Q000502:physiology; D015999:Multivariate Analysis; D011712:Pyramidal Tracts / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012044:Regression Analysis; D020521:Stroke / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014796:Visual Perception / Q000502:physiology
keywords: chronic stroke; corticospinal tract; diffusion tensor imaging; fractional anisotropy; tractography; visual gain