The Dendritic Cytoskeleton as a Computational Device: An Hypothesis

This chapter presents a molecular-dynamical description of the functional role of cytoskeletal elements within the dendrites of a neuron. Our working hypothesis is that the dendritic cytoskeleton, including both microtubules (MTs) and actin filaments plays an active role in computations affecting neuronal function. These cytoskeletal elements are affected by, and in turn regulate, ion-channel activity, MAPs and other cytoskeletal proteins such as kinesin. A major hypothesis we advance here is that the C-termini protruding from the surface of a MT can exist in several conformational states, which lead to collective dynamical properties of the neuronal cytoskeleton. Further, these collective states of the C-termini on MTs have a significant effect on the ionic condensation and ion-cloud propagation that have physical similarities to those recently found in actin filaments. Our objective is to provide an integrated view of these phenomena in a bottom-up scheme. We outline substantial evidence to support our model and contend that ionic wave propagation along cytoskeletal structures impact channel function, and thus the computational capabilities of the dendritic tree and neuronal function at large.