Upper Limb Immobilisation: A Neural Plasticity Model with Relevance to Poststroke Motor Rehabilitation

Figure 1

This figure illustrates the interaction between two prevailing theories of motor recovery after stroke, named here as the “reactivation” and “rebalancing” theories (a), and some of the contemporary motor rehabilitation strategies for treating poststroke upper limb hemiparesis that have been largely underpinned by these theories (b). Red explosion-like balloon: hemiparetic stroke. Light green circle: depression, that is, decreased size and/or excitability, of residual cortical motor representations in the adjacent, perilesional tissue. Dark green circle: overactivity of homologous cortical motor representations in the opposite, undamaged cerebral hemisphere. Light blue arrow: decreased transcallosal inhibition. Dark blue arrow: increased transcallosal inhibition. Red thin downward arrow: reduced use of the paretic upper limb contralateral to the stroke side. Black thin upward arrow: increased skilled use of the paretic upper limb through physiotherapy in the form of task-specific exercises. Red-yellow bolts: adjunctive therapies, such as excitatory and inhibitory brain stimulation (+BS and −BS, resp.) and peripheral somatosensory stimulation (PSS), to be combined with physiotherapy exercises. White tick upward arrow: increase activity in the ipsilesional motor cortex. White tick downward arrow: decrease activity in the contralesional motor cortex. See text for further details.