Contextual Control of Orienting Eye-head Gaze Shifts in the Monkey

Contextual Control of Orienting Eye-head Gaze Shifts in the Monkey
Author: Brendan Blair Chapman
Publisher:
Total Pages: 428
Release: 2011
Genre:
ISBN:

Vision is one of the principal methods used by primates to acquire information about the surrounding environment. As a result, both humans and monkeys have a highly evolved oculomotor system that functions to rapidly relocate the line of sight to areas of interest. These orienting movements are called gaze shifts. Gaze shifts commonly include the coordinated movement of the eyes-in-head and the head-in-space. This thesis examines the muscular and neural control of orienting head movements. The contextual control of behavior is important as it allows one to act appropriately in response to different situations. A common task used to examine the contextual control of behavior is the pro- and anti-saccade task. Pro-saccades simply require a subject to look towards a stimulus. Anti-saccades require a subject to inhibit a movement towards a stimulus in favor of a volitional movement to the diametrically opposite position. This task can reveal capabilities of the oculomotor system and its response to varying behavioral states. To understand the neuromuscular control of orienting head movements during various tasks, we recorded the electromyographic (EMG) activity in ten neck muscles that can orient the head either horizontally or vertically. Recording neck EMGs provides an objective and precise measurement of the neural signals received by neck muscles, circumventing some of the structural and biomechanical complexities of head motion. Chapter two examines neck muscle activity in a pro- and anti-saccade task. Many neural areas and certain neck muscles become active in response to the presentation of a visual stimulus. This visual response on the neck muscles can result in a head turning synergy that orients the head towards the stimulus. By dissociating the typical stimulus-response paradigm, we can analyze if and how the bottom-up visual activity changes in relation to different contexts. A number of cortical and subcortical areas are involved in the generation of correct anti-saccades. By combining EMG recordings while subjects perform this task, we can examine whether top-down task-related activity is present in the neck muscles. This experiment could reveal flexibility in the eye-head gaze shift system that has previously gone unreported. Chapter three will elucidate the supplementary eye field's (SEF) role in the control of orienting eye-head gaze shifts. Neck EMG activity was recorded while providing electrical microstimulation to the SEF in a pro-saccade task Combining EMGs and SEF stimulation permits the systematic examination of cephalomotor commands during head-restrained and head-unrestrained orienting eye-head gaze shifts. The evoked activity of EMGs could reveal functional properties of the neural circuitry between the SEF and the motor related neurons responsible for eye and head movements. The timing and metrics of evoked EMG activity and eye-head gaze shifts are consistent with other frontal areas suggesting a functional role of the frontal cortex in influencing eye-head gaze shifts. Chapter four will combine EMG recordings with SEF stimulation during a pro- and anti-saccade task. The SEF is thought to serve as an interface between high-level cognitive control of gaze shifts and low-level activity associated with the production of saccades. As will be described later in the thesis, neck muscles demonstrate top-down task related activity during anti-saccades. The SEF is a likely candidate for the generation of task-dependent signals observed during anti-saccades. By combining SEF stimulation and neck EMGs in an anti-saccade task, we can reveal if neck muscle activity is modulated by the behavioral task. In summary, this thesis identifies three central themes concerning orienting eye-head gaze shifts. First, chapter two emphasizes the complex interaction of sensori-motor processes in orienting head movements. Second, chapter three attests to the consistent nature of certain areas in frontal cortex and their impact on eye-head gaze shifts. Finally, chapter four demonstrates a potential candidate for influencing the contextual control of cephalomotor commands. Combined, these results highlight the complex interactions of sensori-motor transformations in the motor periphery and emphasize the parallel nature of information processing during the contextual control of eye-head gaze shifts.

The Neurology of Eye Movements : Text and CD-ROM

The Neurology of Eye Movements : Text and CD-ROM
Author: Departments of Neurology R. John Leigh Professor, Neuroscience Otolaryngology and Biomedical Engineering Case Western Reserve University University Hospitals and Veterans Affairs Medical Center Cleveland Ohio
Publisher: Oxford University Press, USA
Total Pages: 658
Release: 1999-08-26
Genre: Medical
ISBN: 0198029705

The Neurology of Eye Movements provides clinicians with a synthesis of current scientific information that can be applied to the diagnosis and treatment of disorders of ocular motility. Basic scientists will also benefit from descriptions of how data from anatomical, electrophysiological, pharmacological, and imaging studies can be directly applied to the study of disease. By critically reviewing such basic studies, the authors build a conceptual framework that can be applied to the interpretation of abnormal ocular motor behavior at the bedside. These syntheses are summarized in displays, new figures, schematics and tables. Early chapters discuss the visual need and neural basis for each functional class of eye movements. Two large chapters deal with the evaluation of double vision and systematically evaluate how many disorders of the central nervous system affect eye movements. This edition has been extensively rewritten, and contains many new figures and an up-to-date section on the treatment of abnormal eye movements such as nystagmus. A major innovation has been the development of an option to read the book from a compact disc, make use of hypertext links (which bridge basic science to clinical issues), and view the major disorders of eye movements in over 60 video clips. This volume will provide pertinent, up-to-date information to neurologists, neuroscientists, ophthalmologists, visual scientists, otalaryngologists, optometrists, biomedical engineers, and psychologists.

Neural Control of Space Coding and Action Production

Neural Control of Space Coding and Action Production
Author: C. Prablanc
Publisher: Gulf Professional Publishing
Total Pages: 334
Release: 2003-02-28
Genre: Medical
ISBN: 9780444509772

Clinical neuropsychology has evolved by integrating in its field the knowledge derived from neuroanatomical, electrophysiological and psychophysical data, and has led to the development of rehabilitation tools. This volume tries to link the new concepts and discoveries in the field of sensorimotor coordination. It contains the main contributions of participants of an international symposium held in Lyon in 2001 entitled "Neural control of space coding and action production". The book emphasizes the reciprocal relationship between perception and action, and the essential role of active sensorimotor organization or reorganization in building up perceptual and motor representations of the self and of the external world.

The Oxford Handbook of Eye Movements

The Oxford Handbook of Eye Movements
Author: Simon Liversedge
Publisher: OUP Oxford
Total Pages: 1048
Release: 2011-08-18
Genre: Psychology
ISBN: 0191626619

In the past few years, there has been an explosion of eye movement research in cognitive science and neuroscience. This has been due to the availability of 'off the shelf' eye trackers, along with software to allow the easy acquisition and analysis of eye movement data. Accompanying this has been a realisation that eye movement data can be informative about many different aspects of perceptual and cognitive processing. Eye movements have been used to examine the visual and cognitive processes underpinning a much broader range of human activities, including, language production, dialogue, human computer interaction, driving behaviour, sporting performance, and emotional states. Finally, in the past thirty years, there have been real advances in our understanding of the neural processes that underpin eye movement behaviour. The Oxford Handbook of Eye Movements provides the first comprehensive review of the entire field of eye movement research. In over fifty chapters, it reviews the developments that have so far taken place, the areas actively being researched, and looks at how the field is likely to devlop in the coming years. The first section considers historical and background material, before moving onto section 2 on the neural basis of eye movements. The third and fourth sections looks at visual cognition and eye movements and eye movement pathology and development. The final sections consider eye movements and reading and language processing and eye movements. Bringing together cutting edge research from and international team of leading psychologists, neuroscientists, and vision researchers, this book is the definitive reference work in this field.

Deducing Neural Strategies for Eye-head Coordination

Deducing Neural Strategies for Eye-head Coordination
Author: Iman Haji-Abolhassani
Publisher:
Total Pages:
Release: 2017
Genre:
ISBN:

"The direction of the eyes in the visual world (gaze) is affected by all body movements and environmental contexts. The system controlling gaze is mainly in the brainstem of the Central Nervous System (CNS) - it drives the gaze to coordinate the eyes and head, acquire different visual stimuli and then fixate on them. Numerous studies have attempted to model this sophisticated structure each having their advantages and drawbacks. Modeling can be done at many levels: e.g., at the behavioral level, neural level (central responses), with and without lesion analysis. So far, no model has tried to integrate known data at all these levels. Thus, the first goal in this thesis was to develop a model to simultaneously replicate observations at all these levels using the same structure and the same parameter set. A new model presented here achieves this goal: it is called the Sensory-Fusion Model (SMF) for gaze orientation. It facilitates the deduction of movement strategies in the CNS, and the prediction of lesions' impacts on gaze control. Another goal of this research was to develop non-invasive protocols and diagnostic tools to detect lesions of the gaze system, in a fast and automatic fashion. Given weaknesses in current algorithms to analyze gaze responses (eye and head trajectories), the results of identification steps are biased and very sensitive to noise. Two new tools solve the problems: fully automatic classification of nystagmus or gaze shift responses, and a novel tool for accurate filtering of nystagmus segments, which enable us to explore gaze system dynamics to a new depth. Finally, the power of these new tools is demonstrated by applying them on simulated gaze data as well as on experimental recordings. Combining model predictions with these analysis methods now allows the design of modern protocols for optimal sensory-motor identification." --

Neurovision: Neural bases of binocular vision and coordination and their implications in visual training programs

Neurovision: Neural bases of binocular vision and coordination and their implications in visual training programs
Author: Olivier A. Coubard
Publisher: Frontiers Media SA
Total Pages: 266
Release: 2015-10-12
Genre: Binocular vision
ISBN: 2889196550

Binocular vision is achieved by five neurovisual systems originating in the retina but varying in their destination within the brain. Two systems have been widely studied: the retino-tectal or retino-collicular route, which subserves an expedient and raw estimate of the visual scene through the magnocellular pathway, and the retino-occipital or retino-cortical route, which allows slower but refined analysis of the visual scene through the parvocellular pathway. But there also exist further neurovisual systems: the retino-hypothalamic, retino-pretectal, and accessory optic systems, which play a crucial role in vision though they are less understood. The retino-pretectal pathway projecting onto the pretectum is critical for the pupillary or photomotor reflex. The retino-hypothalamic pathway projecting onto the suprachiasmatic nucleus regulates numerous behavioral and biological functions as well as circadian rhythms. The accessory optic system targeting terminal lateral, medial and dorsal nuclei through the paraoptic fasciculus plays a role in head and gaze orientation as well as slow movements. Taken together, these neurovisual systems involve 60% of brain activity, thus highlighting the importance of vision in the functioning and regulation of the central nervous system. But vision is first and foremost action, which makes perception impossible without movement. Binocular coordination is a prerequisite for binocular fusion of the object of interest on the two foveas, thus ensuring visual perception. The retino-collicular pathway is sufficient to elicit reflexive eye movements with short latencies. Thanks to its motor neurons, the superior colliculus activates premotor neurons, which themselves activate motor neurons of the oculomotor, trochlear and abducens nuclei. At a higher level, a cascade of neural mechanisms participates in the control of decisional eye movements. The superior colliculus is controlled by the substancia nigra pars reticulata, which is itself gated by subcortical structures such as the dorsal striatum. The superior colliculus is also inhibited by the dorsolateral prefrontal cortex through a direct prefrontotectal tract. Cortical areas are crucial for the triggering of eye movements: the frontal eye field, supplementary eye field, and parietal eye field. Finally the cerebellum maintains accuracy. The focus of the present research topic, entitled Neural bases of binocular vision and coordination and their implications in visual training programs, is to review the most recent findings in brain imaging and neurophysiology of binocular vision and coordination in humans and animals with frontally-placed eyes. The emphasis is put on studies that enable transfer of knowledge toward visual training programs targeting visual field defects (e.g., hemianopia) and binocular functional disorders (e.g., amblyopia).

Eye Movement Disorders

Eye Movement Disorders
Author: E.A.C.M. Sanders
Publisher: Springer Science & Business Media
Total Pages: 276
Release: 2012-12-06
Genre: Medical
ISBN: 9400933177

There is perhaps no area of neuro-ophthalmology that is advancing more rapidly with respect to an understanding of its anatomy and physiology than the ocular motor system. For this reason, it is difficult not only to keep up with the latest information concerning the basic mechanisms involved in the control of eye movements but also to remain up to date regarding the pathophysiology of specific disorders of eye movement. The material in this book is derived from a two-day course on eye movements held in The Netherlands in 1986. The course was designed as an introduction to the normal ocular motor system and to disorders of eye movements and was aimed toward orthoptists, ophthalmolo gists, optometrists, neurologists, and neurosurgeons. The chapters in this book were compiled by a trio of experts in the field of eye movements and contain discussions of anatomy and physiology of the ocular motor system, techniques of examination of patients with diplopia, and pathophysiology of specific disorders of ocular motility. Many of the authors of these chapters are among the most active investigators of eye movements in the world today, and their comments thus reflect the latest information in the field. This text is both basic and com prehensive and thus has something for everyone, from the student just beginning a study of the ocular motor system to the seasoned 'veteran' who wishes to know the latest information regarding central ocular motor control mechanisms. Neil R.

The Oxford Handbook of Eye Movements

The Oxford Handbook of Eye Movements
Author: Simon Liversedge
Publisher: OUP Oxford
Total Pages: 1048
Release: 2011-08-18
Genre: Psychology
ISBN: 0191626619

In the past few years, there has been an explosion of eye movement research in cognitive science and neuroscience. This has been due to the availability of 'off the shelf' eye trackers, along with software to allow the easy acquisition and analysis of eye movement data. Accompanying this has been a realisation that eye movement data can be informative about many different aspects of perceptual and cognitive processing. Eye movements have been used to examine the visual and cognitive processes underpinning a much broader range of human activities, including, language production, dialogue, human computer interaction, driving behaviour, sporting performance, and emotional states. Finally, in the past thirty years, there have been real advances in our understanding of the neural processes that underpin eye movement behaviour. The Oxford Handbook of Eye Movements provides the first comprehensive review of the entire field of eye movement research. In over fifty chapters, it reviews the developments that have so far taken place, the areas actively being researched, and looks at how the field is likely to devlop in the coming years. The first section considers historical and background material, before moving onto section 2 on the neural basis of eye movements. The third and fourth sections looks at visual cognition and eye movements and eye movement pathology and development. The final sections consider eye movements and reading and language processing and eye movements. Bringing together cutting edge research from and international team of leading psychologists, neuroscientists, and vision researchers, this book is the definitive reference work in this field.