Resilience of Brain Networks After Stroke

Abstract

How do brain networks anticipate, endure, respond, and adapt to limit the consequences of a stroke? Recent studies suggest that understanding the whole process of resilience of brain networks may create new opportunities in the management of patients. The first step of resilience relates to the status of brain networks before the stroke has occurred. In healthy subjects, brain networks seem to be organized to limit the consequences of a lesion. Indeed, the anatomic location and the position of strategic nodes in the network architecture prevent major neurological deficits, even when these hubs suffer from a targeted attack. The second step in the process of resilience reflects how the brain endures the impact of stroke. Widespread changes in the organization of brain networks are triggered by the lesion. This effect can be understood as “connectional” diaschisis or “connectomal” diaschisis defined, respectively, as the changes in coupling between two nodes of a specific network or in the totality of brain connections. Clinically, the reduction in interhemispheric coupling after stroke seems to be particularly relevant. Further steps in the process of resilience include response and adaptation to the lesion. Recent evidence points to the importance of changes in network configuration during recovery. However, it remains debated whether normalization or reorganization of brain networks in a most efficient architecture will lead to a favorable outcome. Based on the concept of resilience, further studies are needed to determine how therapeutic strategies may promote an optimal architecture of brain networks to improve functional outcome.