Abstract Jack Tuszynski

Abstract

Molecular Models of Information Processing, Memory Encoding and the Action of Anesthetics at the Level of Individual Neurons with Connections to Neurological Disorders

A model describing information processing pathways in dendrites is proposed based on electrodynamic signaling mediated by the cytoskeleton. 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, a key element of neuronal information processing, namely, dendritic ion channel activity. We present a molecular dynamics description of the C-termini protruding from the surface of a MT that reveals the existence of several conformational states, which lead to collective dynamical properties of the neuronal cytoskeleton. Furthermore, these collective states of the C-termini on MTs have a significant effect on ionic condensation and ion cloud propagation with physical similarities to those recently found in actin-filaments and microtubules. We also discuss experimental findings concerning both intrinsic and ionic conductivities of microfilaments and microtubules which strongly support our hypothesis regarding internal processing capabilities in neurons. Our ultimate objective is to provide an integrated view of these phenomena in a bottom-up scheme, demonstrating that ionic wave interactions and propagation along cytoskeletal structures impacts channel functions, and thus neuronal computational capabilities. The issue of quantum versus classical character of these interactions will be discussed. As consequences of the model we discuss how information process takes place inside a neuron, how memory can be encoded and erased within the cytoskeleton and show how molecular dynamics simulations reveal the action of anesthetics. Direct connections are listed to a host of neurological disorders including Alzheimer's disease.