Is lesion-induced synaptic rewiring driven by activity homeostasis?

Butz-Ostendorf, M., and Van Ooyen, A. (2017). In: Van Ooyen, A., and Butz-Ostendorf, M., eds. The Rewiring Brain: A Computational Approach to Structural Plasticity in the Adult Brain. San Diego: Academic Press, pp. 71-92. [Full text: PDF]

Abstract

Synaptic connectivity undergoes substantial rewiring in response to changes in afferent activity that are caused by lesions such as amputation or stroke. The principles governing activity-dependent synaptic rewiring are, however, unclear. Here, we argue that neurons, by making new synaptic connections or breaking existing ones, try to maintain their average electrical activity at a desired level. We review experimental studies indicating that activity homeostasis may drive the spine dynamics and axonal and dendritic remodeling that underlie the restructuring of synaptic connectivity. These studies suggest that neurons create new dendritic spines and axonal boutons when neuronal activity is below a homeostatic set-point and delete spines and boutons when activity is above the set-point or below a certain minimum level. We discuss how homeostatic structural plasticity could be tested experimentally and how this form of plasticity may inspire novel treatments for stimulating brain repair after stroke or neurodegeneration.