• Katrine Leander Sørensen
  • Rasmus Kragh Nielsen
  • Daniel Simonsen
Cerebral ischemia is caused by occlusion of the vascular supply in a local region of the brain, and 85 % of all strokes are ischemic of nature. One of the major consequences of ischemic stroke is motor dysfunction such as a decrease in the walking ability. In relation to rehabilitation post stroke, two terms are used "true recovery", implying restoration of the neurological circuitry, and "behavioral compensation", implying alterations of the neurological circuitry, which was in place pre stroke. The aim of rehabilitative training is to obtain the largest possible degree of "true recovery" , and has previously been related to the onset time of rehabilitation. The aim of the present study was to investigate the effects of ischemic stroke and onset of subsequent rehabilitation related to gait function in rats, by development and utilisation of a novel rat model of ischemic stroke. Nine male Spraque-Dawley rats (350 - 400 g) were instrumented with a 16-channel intracortical (IC) electrode array. Stroke was induced by the photothrombosis method, within the hindlimb area of the left hemisphere, and rehabilitation consisted of a repetitive training paradigm over 28 days, initiated on day one and seven for intervention group 1 and 2, respectively. Data were obtained from IC microstimulation tests, treadmill walking tests, and beam walking tests. Results revealed an expansion of the hindlimb representation, and an increased firing rate modulation size post stroke for intervention group 1, but not for intervention group 2. Residuals and centre of gravity for marker trajectories revealed a significant change pre to post stroke for both intervention groups. Results from the beam walking test showed functional performance deficits, which though returned to baseline level. The results from the present study emphasise the existence of a critical period. In conclusion, the results indicate that rehabilitation onset time within the critical period is related to a higher degree of "true recovery". Further, a novel rat model of ischemic stroke was successfully developed.
Publication date1 Jun 2012
Number of pages104
ID: 63497584