Format:
Online-Ressource (xiii, 144 pages)
,
illustrations.
Edition:
Also available in print
ISBN:
9781627055475
Series Statement:
Synthesis lectures on biomedical engineering # 53
Content:
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. 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 Part 1, early models of saccades and smooth pursuit are presented. A number of oculomotor plant models are described therein 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. In this book, a multiscale model of the saccade system is presented, focusing on the neural network. Chapter 1 summarizes a whole muscle model of the oculomotor plant based on the 2009 3rd-order and linear, and controlled by a physiologically based time-optimal neural network. Chapter 2 presents a neural network model of biophysical neurons in the midbrain for controlling oculomotor muscles during horizontal human saccades. To investigate horizontal saccade dynamics, a 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. A generic neuron model serves as the basis to match the characteristics of each type of neuron in the neural network. We wish to express our thanks to William Pruehsner for drawing many of the illustrations in this book.
Content:
1. 2009 linear homeomorphic saccadic eye movement model -- 1.1 Introduction -- 1.2 Oculomotor plant -- 1.2.1 Derivation of the differential equation describing the oculomotor system -- 1.2.2 Neural input -- 1.2.3 Saccade response -- 1.3 Parameter estimation and system identification -- 1.3.1 System identification -- 1.3.2 Numerical gradient -- 1.3.3 Velocity and acceleration estimation -- 1.3.4 Inverse filter -- 1.4 Initial parameter estimation for humans -- 1.4.1 Estimation of the start time and duration of a saccade -- 1.4.2 Estimation of model parameters -- 1.4.3 Estimation of parameters for the agonist muscle -- 1.4.4 Estimation of parameters for antagonist muscle -- 1.4.5 Corrections -- 1.4.6 Implementation -- 1.5 Initial parameter estimation for monkeys -- 1.5.1 Static conditions -- 1.5.2 Force-velocity characteristics -- 1.5.3 Oculomotor plant parameters -- 1.6 Monkey data and results -- 1.7 Human data and results -- 1.8 Post-inhibitory rebound burst and post-saccade phenomena -- 1.9 Time-optimal controller --
Content:
2. A neuron-based time-optimal controller of horizontal saccadic eye movements and glissades -- 2.1 Introduction -- 2.2 Neural network -- 2.2.1 Superior colliculus -- 2.2.2 Premotor neurons in the PPRF -- 2.2.3 Omnipause neuron -- 2.2.4 Tonic neuron -- 2.2.5 Interneuron -- 2.2.6 Abducens nucleus -- 2.2.7 Oculomotor nucleus -- 2.2.8 Cerebellum -- 2.3 Firing characteristics of each type of neuron -- 2.3.1 Neural activity -- 2.3.2 Burst discharge mechanism -- 2.3.3 Sequence of neural firing -- 2.4 Neural modeling -- 2.4.1 Dendrite model -- 2.4.2 Axon model -- 2.4.3 Synapse model -- 2.5 Neural stimulation of the linear homeomorphic model of muscle -- 2.6 Neural system implementation -- 2.6.1 Simulink programming -- 2.6.2 Control simulation results -- 2.7 Glissades as one of the deficiencies in the oculomotor control mechanism -- 2.8 Glissade dynamics -- 2.8.1 Analysis and characteristics -- 2.8.2 Neural controller with PIRB -- 2.8.3 Comparison of glissades to normal saccades --
Content:
References -- Authors' biographies
Note:
Part of: Synthesis digital library of engineering and computer science. - Includes bibliographical references (pages 135-141). - Compendex. INSPEC. Google scholar. Google book search. - Title from PDF title page (viewed on November 19, 2014)
,
Includes bibliographical references (pages 135-141)
,
Part of: Synthesis digital library of engineering and computer science
,
Also available in print.
,
Mode of access: World Wide Web.
,
System requirements: Adobe Acrobat Reader.
Additional Edition:
ISBN 9781627055468
Additional Edition:
Erscheint auch als Druck-Ausgabe ISBN 9781627055468
Language:
English
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