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Fri, Dec 17

Speaker: Karen Morris (Dr. Rymer's group)

Title: Mechanisms of spasticity in stroke, the contribution of serotonergic changes in motoneuron behavior

Abstract:  Two stereotypical clinical changes that occur post-stroke are spasticity and hyperreflexia. Post-stroke hyperreflexia occurs when the Ia homonomous stretch reflex pathway is activated by smaller EPSPs than on the unaffected side or in healthy intacts. It is unclear what CNS mechanism could make this reflex loop hyperexcitable. One hypothesis is the CNS may be releasing more excitatory drive after a cortical lesion. The drive may come in the form of increased levels of monoaminergic output from the brainstem. This discussion will address the effects of monoamines on motoneuron behavior post-stroke as compared to healthy, age-matched intacts. The effects of monoamines on human motor control have been largely unexplored due to the difficulties of directly observing and quantifying monoaminergic activity in humans.

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Speaker: Sheena Sharma (Dr. Stinear's group)

Title: Anticipatory Postural Adjustments During a Stepping Task in chronic stroke

Abstract:  Asymmetric gait and increased fall rates are common consequences of stroke. Current therapies for these issues include gait and balance training, however after therapy, 90% will never completely recover. Fall rate may be linked to delayed anticipatory postural adjustments (APAs). Few recent electromyography studies have reported delayed APAs in stroke patients with a latency asymmetry existing between both sides of the body. Few studies investigate the cortical excitability of APAs during gait initiation in stroke subjects. This current line of research investigates how APAs change in a gait initiation paradigm post stroke, and how APAs can potentially be modulated, leading to increased stability post stroke.