http://nnr.sagepub.com/content/27/9/900.abstract?etoc
- Crystal L. MacLellan, MScPT, PhD1
- Kristopher D. Langdon, PhD2,3
- Alex Botsford, BSc2
- Stephanie Butt, BSc2
- Dale Corbett, PhD2,3,4,5
- 1University of Alberta, Edmonton, AB, Canada
- 2Memorial University of Newfoundland, St John’s, NF, Canada
- 3Heart and Stroke Foundation Centre for Stroke Recovery, Ottawa, ON, Canada
- 4University of Ottawa, ON, Canada
- 5University of Toronto, ON, Canada
- Crystal L. MacLellan, MScPT, PhD, Department of Physical Therapy, University of Alberta, 2-50 Corbett Hall, Edmonton, AB, T6G 2G4, Canada. Email: clmac@ualberta.ca
Abstract
Background. After hemiplegic stroke, people often rely on their unaffected limb to complete activities of daily living. A component
of residual motor dysfunction involves learned suppression of movement, termed learned nonuse.
Objective. To date, no rodent stroke model of persistent learned nonuse has been described that can facilitate understanding of this
phenomenon and test interventions to overcome it.
Methods.
Rats were trained in the staircase skilled-reaching and limb use
asymmetry (cylinder) tasks. Endothelin-1 was injected into
the cortex and striatum to create focal ischemia.
Starting 7 days poststroke, half of the rats (ipsilateral training; n =
15) were trained to reach for food reward pellets
in the tray-reaching task with the ipsilateral forelimb. Training lasted
20 days. Rats in the control group (control; n =
15) did not receive training. All rats then remained in their home cages
for an additional 30 days. Performance on the
cylinder and staircase tasks was assessed ~2 months poststroke.
Results.
Ischemia caused significant functional impairments in all rats.
Significant contralateral forelimb skilled-reaching recovery
was evident in the control group at 2 months but
not the ipsilateral training group. There was no difference in
performance
in the cylinder task. Similarly, the volume of
brain injury (~66 mm3) was similar between groups. Ipsilateral forelimb training reduced poststroke motor recovery. Conclusion. This rodent model of persistent nonuse after stroke may be used to further understand mechanisms of learned nonuse as well
as to evaluate pharmacological and rehabilitation treatments to overcome it.
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