Modelling: The Oculomotor Systems, Volume 269 in the Progress in Brain Research serial highlights new advances in the field with this new volume presenting interesting chapters on topics including The function and phylogeny of eye movements, The behavior of motoneurons, Statics of plant mechanics, Dynamics of plant mechanics, The functional operation of the vestibulo-ocular reflex, Basic framework of the vestibulo-ocular reflex, Oculomotor signals, Signal processing in the vestibulo-ocular reflex, Plasticity and repair of the vestibulo-ocular reflex, The behavior of the optokinetic system, Models of the optokinetic system, Neurophysiology of the optokinetic system, and much more. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in Progress in Brain Research serial Includes the latest information on Modelling: The Oculomotor Systems

This monograph is a structured review of models of oculomotor control systems that is geared toward biomedical engineers, vision scientists, and optometry students. It aims to provide the biomedical engineer with a thorough understanding of how various engineering control principles are applied to oculomotor systems, and the non-engineer with knowledge of how various physiological and clinical concepts can be represented quantitatively and efficiently by control system models.Basic control system concepts and oculomotor physiology are first introduced, along with a glossary, to provide background for the more advanced topics. Then, these concepts are applied to static linear and nonlinear analysis of various oculomotor systems. In addition, advanced topics are presented on the application of dynamic linear and nonlinear modeling techniques to the oculomotor system, with a particular emphasis on myopia development. This book can thus serve as a unique reference for quantitative analysis of oculomotor control, and as a foundation for future research on the oculomotor system.

There are five different types of eye movements: saccades, smooth pursuit, vestibular ocular eye movements, optokinetic eye movements, and vergence eye movements. The purpose of this book is focused primarily on mathematical models of the horizontal saccadic eye movement system and the smooth pursuit system, rather than on how visual information is processed. A saccade is a fast eye movement used to acquire a target by placing the image of the target on the fovea. Smooth pursuit is a slow eye movement used to track a target as it moves by keeping the target on the fovea. The vestibular ocular movement is used to keep the eyes on a target during brief head movements. The optokinetic eye movement is a combination of saccadic and slow eye movements that keeps a full-field image stable on the retina during sustained head rotation. Each of these movements is a conjugate eye movement, that is, movements of both eyes together driven by a common neural source. A vergence movement is a non-conjugate eye movement allowing the eyes to track targets as they come closer or farther away. In this book, a 2009 version of a state-of-the-art model is presented for horizontal saccades that is 3rd-order and linear, and controlled by a physiologically based time-optimal neural network. The oculomotor plant and saccade generator are the basic elements of the saccadic system. The control of saccades is initiated by the superior colliculus and terminated by the cerebellar fastigial nucleus, and involves a complex neural circuit in the mid brain. This book is the second part of a book series on models of horizontal eye movements. Table of Contents: 2009 Linear Homeomorphic Saccadic Eye Movement Model and Post-Saccade Behavior: Dynamic and Glissadic Overshoot / Neural Network for the Saccade Controller

There are five different types of eye movements: saccades, smooth pursuit, vestibular ocular eye movements, optokinetic eye movements, and vergence eye movements. The purpose of this book series is focused primarily on mathematical models of the horizontal saccadic eye movement system and the smooth pursuit system, rather than on how visual information is processed. In Part 1, early models of saccades and smooth pursuit are presented. A number of oculomotor plant models are described here beginning with the Westheimer model published in 1954, and up through our 1995 model involving a 4th order oculomotor plant model. In Part 2, a 2009 version of a state-of-the-art model is presented for horizontal saccades that is 3rd-order and linear, and controlled by a physiologically based time-optimal neural network. Part 3 describes a model of the saccade system, focusing on the neural network. It presents a neural network model of biophysical neurons in the midbrain for controlling oculomotor muscles during horizontal human saccades. In this book, a multiscale model of the saccade system is presented, focusing on a multiscale neural network and muscle fiber model. Chapter 1 presents a comprehensive model for the control of horizontal saccades using a muscle fiber model for the lateral and medial rectus muscles. The importance of this model is that each muscle fiber has a separate neural input. This model is robust and accounts for the neural activity for both large and small saccades. The muscle fiber model consists of serial sequences of muscle fibers in parallel with other serial sequences of muscle fibers. Each muscle fiber is described by a parallel combination of a linear length tension element, viscous element, and active-state tension generator. Chapter 2 presents a biophysically realistic neural network model in the midbrain to drive a muscle fiber oculomotor plant during horizontal monkey saccades. Neural circuitry, including omnipause neuron, premotor excitatory and inhibitory burst neurons, long lead burst neuron, tonic neuron, interneuron, abducens nucleus, and oculomotor nucleus, is developed to examine saccade dynamics. The time-optimal control mechanism demonstrates how the neural commands are encoded in the downstream saccadic pathway by realization of agonist and antagonist controller models. Consequently, each agonist muscle fiber is stimulated by an agonist neuron, while an antagonist muscle fiber is unstimulated by a pause and step from the antagonist neuron. It is concluded that the neural network is constrained by a minimum duration of the agonist pulse, and that the most dominant factor in determining the saccade magnitude is the number of active neurons for the small saccades. For the large saccades, however, the duration of agonist burst firing significantly affects the control of saccades. The proposed saccadic circuitry establishes a complete model of saccade generation since it not only includes the neural circuits at both the premotor and motor stages of the saccade generator, but it also uses a time-optimal controller to yield the desired saccade magnitude. Table of Contents: Acknowledgments / A New Linear Muscle Fiber Model for Neural Control of Saccades\footnotemark / A Physiological Neural Controller of a Muscle Fiber Oculomotor Plant in Horizontal Monkey Saccades\footnotemark / References / Authors' Biographies