1. Group differences in anterior and posterior CP:
What deficits are there following a stroke?2
What happens to the brain after stroke?1
What is diffusion-weighted magnetic resonance imaging?3
Quantifying the Microstructure of the Corticospinal Tract in Chronic Stroke
Marble, S.1, Archer, D.B.1, Coombes, S.A.1
1Laboratory for Rehabilitation Neuroscience. www.lrnlab.org Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
Laboratory for Rehabilitation Neuroscience
Contact: Shannon Marble, smarble94@ufl.edu
This work was supported in part by the James and Esther
King Biomedical Research Program.
A. Impaired Hemisphere B. Unimpaired Hemisphere C. Asymmetries
lrnlab.org
Corticospinal Tract Posterior Visual Tract
Questions to be answered with this experiment:5
What is the corticospinal tract?4
6
aCP and handbump predict strength.8
Group differences in handbump and PLIC:7
Results and Conclusions9
References
[1] Abdollahi, F. Neurorehabil Neural Repair. (2013)
[2] Patton, J.L. Exp Brain Res. (2006)
[3] Coombes, S.A. Neurophysiol. (2010)
[4] Park, C.H. Neuroimage Clin. (2013)
[5] Schaechter, J.D. Neuroimage. (2008)
Figure 1. Elderly individuals are more likely to suffer from a stroke. After an individual
suffers a stroke, one hemisphere of the brain is impaired.
Following a stroke, an individual can have a wide range of deficits.
The type of deficit an individual will have depends on the location
of the stroke. Below is a list of common deficits in individuals post-
stroke:
• Motor Impairments
• Loss sense of touch
• Loss of urinary continence
• Visual Problems
• Chronic Pain
• Language
• Memory
• Emotion
Fibers in the corticospinal tract are crucial in
performing movement and control the hands
and fingers in precise and skilled voluntary
movements, including writing or grasping
objects, by transmitting electrical signals from
the cerebrum to spinal cord motor neurons.
Regions like the cerebral peduncle (CP) and
the posterior limb of the internal capsule
(PLIC) are components of the corticospinal
tract that contribute to these voluntary
movements.
Diffusion-weighted magnetic resonance imaging is an imaging
method that uses the movement of water molecules to generate
contrast in MR images. It allows the mapping of
the diffusion process of molecules in biological tissues, in
vivo and non-invasively.
• Fractional Anisotropy is a measure often used
in diffusion imaging that describes the degree
of anisotropy of a diffusion process. It is thought to
reflect fiber density, axonal diameter,
and myelination in white matter.
Question 1: Is brain microstructure and fractional anisotropy
deficit in post-stroke individuals?
Question 2: Does fractional anisotropy correlate with grip
strength?
• While there were no group differences in the cortical areas or the
CP, there was a drastic reduction in FA within the PLIC (p<0.05).
• The aCP (r=0.580;p<0.01) and the handbump (r=0.434;p<0.05)
were predictive of grip strength in chronic stroke individuals.
• Using diffusion MRI within regions of the CST could be a
potential aid in the creation of new treatments for chronic stroke
individuals.
Figure 3: Bar charts comparing the different integrities of the aCP (A) and pCP (B)
tested between the stoke and control groups.
Unimpaired HemisphereImpaired Hemisphere
Unimpaired HemisphereImpaired Hemisphere
Figure 4: Bar charts comparing the different integrities of the PLIC (A) and handbump
(B) tested between the stoke and control groups.
Figure 2: The corticospinal
tract.
Figure 5: The association of integrity of the aCP (A) and handbump (B) with grip
strength (MVC).