Neural plasticity and its contribution to functional recovery

Abstract

In this chapter we address the phenomena of neural plasticity, operationally defined as the ability of the central nervous system to adapt in response to changes in the environment or lesions. At the cellular level, we discuss basic changes in membrane excitability, synaptic plasticity as well as structural changes in dendritic and axonal anatomy that support behavioral expressions of plasticity and functional recovery. We consider the different levels at which these changes can occur and possible links with modification of cognitive strategies, recruitment of new/different neural networks, or changes in strength of such connections or specific brain areas in charge of carrying out a particular task (i.e., movement, language, vision, hearing). The study of neuroplasticity has wide-reaching implications for understanding reorganization of action and cognition in the healthy and lesioned brain.

Fig. 1.1

The currently described influences of other brain areas on the output of the primary motor cortex (M1) are shown. Open arrows denote facilitation, while filled arrows denote inhibition. In many cases the influence shown represents a net effect of several specific interactions, whose details are discussed in the relevant section of the text and are shown in subsequent figures. These influences include projections from motor areas in the ipsi- and contralateral hemispheres and the effects of afferent sensory input. PMd = dorsal premotor cortex; PMv = ventral premotor cortex; SMA = supplementary motor area; PPC = posterior parietal cortex; CBL = cerebellum; THAL = thalamus; PNS = peripheral nervous system. (Figure reproduced with permission from Reis et al., 2008b.)