A detailed model of homeostatic structural plasticity based on dendritic spine and axonal bouton dynamics

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. 155-176.

Abstract

Since the late 1960s, neurobiologists have been exploring how network connectivity in the brain changes (structural plasticity) in response to central or peripheral lesions. Although recent imaging studies enable time-lapse in vivo imaging of subcellular structures, such as dendritic spines and axonal boutons, understanding the guiding principles of structural plasticity requires the support of detailed theoretical models.

Our Model of Structural Plasticity is the first to provide a degree of detail that is high enough to make predictions on spine and bouton dynamics after lesions yet simple enough to help decipher the driving forces of structural plasticity. We find that a simple rule for spine and bouton formation based on a neuron’s need for activity homeostasis can govern network reorganization following loss of input as caused by, e.g., retinal lesions. According to this rule, a neuron creates new spines and boutons when its level of electrical activity is below a homeostatic set-point and deletes spines and boutons when its activity is above this set-point or below a certain minimum level. The growth rule produces neuron and network changes as observed experimentally after lesions, with activity restoration for small peripheral lesions, remapping of spatially organized inputs, massive spine turnover, axonal sprouting, and characteristic alterations in network topology.

Taken together, our results suggest that homeostatic structural plasticity may provide a unifying framework for understanding compensatory network reorganization, including network repair in neurodegenerative diseases or following stroke.