Poststroke neuroplasticity processes

The paper considers different aspects of neuroplasticity in patients with stroke. It underlines the dynamism of this process and the ambiguity of involvement of the structures of the contralateral cerebral hemisphere in the restorative process. It considers the periods after onset of stroke and the activation of different brain regions (of both the involved and intact hemisphere) in the poststroke period. Particular emphasis is placed on the issues of neurorehabilitation in this category of patients. Delay in rehabilitation measures leads to a worse outcome, the patients must be at hospital longer. It is emphasized that the neurorehabilitaton measures should use strategies aimed at improving plasticity processes at the level of synaptic transmission and neuronal communications. At the same time, of great importance are the processes of structural and functional remodeling of neuronal communications with the involvement of surviving neurons that are located in the peri-infarct area and partially damaged during ischemia. To recover stroke-induced lost motor functions, measures are implemented to modulate the ipsilateral motor cortex, contralateral motor cortex, and sensory afferentation. Remodeling processes, one of the manifestations of neuroplasticity, vary with the size and location of an ischemic focus. The specific features of this process with subcortical and cortical foci are considered. It is stressed that there are genetically determined neurotrophic factors that may enhance remodeling processes in the peri-infarct area, as well as factors that inhibit these processes. The sensory system is noted to have a high potential of compensation, which is appreciably associated with the considerable extent of sensory fibers even at the level of the cerebral cortex.