Paradoxical Motor Recovery From a First Stroke After Induction of a Second Stroke: Reopening a Postischemic Sensitive Period.
Neurorehabil Neural Repair. 2015 Dec 31;
Authors: Zeiler SR, Hubbard R, Gibson EM, Zheng T, Ng K, O'Brien R, Krakauer JW
Abstract
BACKGROUND AND OBJECTIVE: Prior studies have suggested that after stroke there is a time-limited period of increased responsiveness to training as a result of heightened plasticity-a sensitive period thought to be induced by ischemia itself. Using a mouse model, we have previously shown that most training-associated recovery after a caudal forelimb area (CFA) stroke occurs in the first week and is attributable to reorganization in a medial premotor area (AGm). The existence of a stroke-induced sensitive period leads to the counterintuitive prediction that a second stroke should reopen this window and promote full recovery from the first stroke. To test this prediction, we induced a second stroke in the AGm of mice with incomplete recovery after a first stroke in CFA.
METHODS: Mice were trained to perform a skilled prehension (reach-to-grasp) task to an asymptotic level of performance, after which they underwent photocoagulation-induced stroke in CFA. After a 7-day poststroke delay, the mice were then retrained to asymptote. We then induced a second stroke in the AGm, and after only a 1-day delay, retrained the mice.
RESULTS: Recovery of prehension was incomplete when training was started after a 7-day poststroke delay and continued for 19 days. However, a second focal stroke in the AGm led to a dramatic response to 9 days of training, with full recovery to normal levels of performance.
CONCLUSIONS: New ischemia can reopen a sensitive period of heightened responsiveness to training and mediate full recovery from a previous stroke.
PMID: 26721868 [PubMed - as supplied by publisher]
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