Summary

The human brain has a great potential for reorganizing itself after lesions to regain lost function. In recent years, functional imaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have revealed complex changes in cortical networks that are functionally relevant for recovery of function following stroke. In this chapter, we demonstrate how stroke may influence cortical activity over time depending on structural damage and functional outcome. We furthermore discuss different techniques to modulate human brain function, e.g. via pharmacological interventions and transcranial magnetic stimulation (TMS), and their effects on cortical activity in both healthy subjects and patients. Assessing the changes in cortical network architecture following neuromodulation in individual patients will help to design novel treatment strategies based on neurobiological principles to minimize functional impairment resulting from brain lesions.

Introduction

As discussed in the preceding chapters, stroke is the leading cause of permanent disability in Europe and the USA (Gresham et al., 1975; Whisnant, 1984; Taylor et al., 1996) (see Chapters 21 and 29). Treatment of stroke patients in specialized facilities such as neurological intensive care and stroke units has led to a significant reduction of mortality rates in the acute stage of cerebral ischemia or hemorrhage in the past decades (Howard et al., 2001). This positive development is, however, associated with an increasing number of people living with residual neurological symptoms such as hemiparesis, aphasia or other neuropsychological deficits.