Repairing the human brain after stroke: I. Mechanisms of spontaneous recovery

Abstract

Stroke remains a leading cause of adult disability. Some degree of spontaneous behavioral recovery is usually seen in the weeks after stroke onset. Variability in recovery is substantial across human patients. Some principles have emerged; for example, recovery occurs slowest in those destined to have less successful outcomes. Animal studies have extended these observations, providing insight into a broad range of underlying molecular and physiological events. Brain mapping studies in human patients have provided observations at the systems level that often parallel findings in animals. In general, the best outcomes are associated with the greatest return toward the normal state of brain functional organization. Reorganization of surviving central nervous system elements supports behavioral recovery, for example, through changes in interhemispheric lateralization, activity of association cortices linked to injured zones, and organization of cortical representational maps. A number of factors influence events supporting stroke recovery, such as demographics, behavioral experience, and perhaps genetics. Such measures gain importance when viewed as covariates in therapeutic trials of restorative agents that target stroke recovery.

Multimodal Examination of Structural and Functional Remapping in the Mouse Photothrombotic Stroke Model

“…2 These data in the human suggest that stroke induces a process of neuroplasticity in the peri-infarct cortex that leads to changes in motor and sensory maps and recovery of function. 3 Animal studies indicate that remapping of the sensorimotor function in the peri-infarct cortex after stroke may be associated with the formation of new connections. In primates, motor cortex lesions induce long-distance axonal sprouting.…”

Adapted Tai Chi Enhances Upper Limb Motor Control in Chronic Stroke Patients: A Pilot Study

“…Given the exploratory nature of this study, we did not include a control group. However, since all participants in this study were in a chronic stage post stroke ( ≥ 8 months after stroke onset), it is unlikely that the gains identified were only due to improvements from spontaneous recovery [47,48]. Moreover, the changes of the FMA, WMFT functional scale and performance time in the study are larger than their corresponding values of minimal detectable change at the 95% confidence level (5.2 points, 0.1 points, 0.7 sec respectively) [49,50].…”

Exercise and Environmental Enrichment as Enablers of Task-Specific Neuroplasticity and Stroke Recovery

“…The existence of a similar Bgrowth-permissive^period may exist with respect to cognition. Clinically, spontaneous recovery of cognitive function continues beyond the 3-4-month poststroke period when motor recovery plateaus [41], suggestive of a broader cognitive therapeutic time window. The development of stroke models that target cognitive function will hopefully lead to new insights into the nature of poststroke cognitive and psychosocial recovery [42,43].…”