Forelimb Ladder Experiment

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The purpose of this experiment was to compare rat forelimb preference in the cylinder task and performance on the horizontal ladder task before and after ischemic stroke in the left motor cortex. This demonstrates the behavioural effects of ischemic strokes in localized brain regions, including motor areas. Our results implicate the motor cortex in the production of voluntary movement, and illustrate the effect of neuronal death on this behaviour. These results support our hypotheses, revealing that stroke produces deficits in horizontal ladder task performance and decreases forelimb preference for the limb contralateral to the stroke region. Our results for the horizontal ladder task found that, on the side contralateral to where stroke…show more content…
It is also likely that the rat forepaws could not fit through this gap, and that fewer errors were recorded simply due to the close spacing of the rungs. In the ‘1-Irregular’ condition, it is possible that compensatory changes in locomotion to the stroke occurred. This is unlikely, however, as the purpose of irregular spacing is to control for post-stroke compensation (Metz and Whishaw, 2009). All other ladder conditions showed an increase in paw slip errors post-stroke, including the regular patterns. This suggests that rats were unable to compensate behaviourally to the regular patterns post-stroke. Regardless, literature shows that compensatory behaviours occur on the horizontal ladder task within a few sessions (Metz and Whishaw, 2002; Metz et al., 2005). However, our rats only performed three trials for each condition on the horizontal ladder over one day. Thus, the compensatory mechanisms may have needed more time to develop in response to stroke. Results from the cylinder task showed a significant increase in left forelimb preference (with a corresponding decrease in right forelimb preference) after ischemic stroke induced in the left motor cortex, supporting our hypothesis. This is most likely due to the stroke in the left forelimb motor area making it difficult to control digit movements, wrist extension, elbow flexion, and shoulder movements for the right limb (Neafsey and Sievert, 1982; Tennant et al., 2011). Therefore, the left forelimb would be
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