The role of neural cell adhesion molecules in plasticity and repair

Repair and functional recovery after brain injury critically depends on str uctural and functional plasticity of preserved neuronal networks. A strikin g feature of brain structures where tissue reorganization and plasticity oc cur is a strong expression of the polysialylated neural cell adhesion molec ule (PSA-NCAM). An important role of this molecule in various aspects of ne uronal and synaptic plasticity has been revealed by many studies. Recently, a new mechanism has been elucidated whereby PSA-NCAM may contribute to sig nalling mediated by the neurotrophic factor BDNF, thereby sensitizing neuro ns to this growth factor. This mechanism was shown to be important for acti vity-induced synaptic plasticity and for the survival and differentiation o f cortical neurons. A cross-talk between these molecules may, thus, reveal a key factor for properties of structural plasticity and in particular coul d mediate the activity-dependent aspects of synaptic network remodeling. An imal models have been developed to assess the role of these molecules in fu nctional recovery after lesions. (C) 2001 Elsevier Science B.V. All rights reserved.