Visual Control Of Locomotion

This Element examines visual perception in the context of activities that involve moving about in complex, dynamic environments. A central theme is that the ability of humans and other animals to perceive their surroundings based on vision is profoundly shaped by the need to adaptively regulate locomotion to variations in the environment. As such, important new insights into what and how we perceive can be gleaned by investigating the connection between vision and the control of locomotion. I present an integrated summary of decades of research on the perception of self-motion and object motion based on optic flow, the perception of spatial layout and affordances, and the control strategies for guiding locomotion based on visual information. I also explore important theoretical issues and debates, including the question of whether visual control relies on internal models.

The accomplishments were threefold. First, a software tool for rendering virtual environments was developed, a tool useful for other researchers interested in visual perception and visual control of action. Second, an instrumented electric scooter was developed that allows a person to drive around in virtual reality while experiencing the normal inertial cues associated with physical motion. This type of research vehicle can be used to investigate the roles of visual and inertial cues in the control of locomotion. Third, a number of behavioral experiments were conducted in real and virtual environments. The principal research findings were these: (1) complex behaviors, like steering a curved path and ball catching, can be performed without the retinal motion associated with luminance-based stimulation, (2) visual control of posture depends on the sensed relative motion between self and environment instead of on "optic flow", (3) people can continue steering a vehicle after the loss of visual information, implicating an internal model of surrounding space, (4) a steering error observed while driving with visual information only is eliminated when inertial cues.

This book is an attempt to advance the discussion and improve our understanding about the effects of aging and movement disorders on motor control during walking and postural tasks. Despite these activities are performed daily, there is a high requirement of motor and neural systems in order to perform both tasks efficiently. Both walking and posture require a complex interaction of musculoskeletal and neural systems. However, the mechanisms used to control these tasks, as well as how they are planned and coordinated, are still a question of discussion among health professionals and researchers. In addition, this discussion is more interesting when the effects of aging are included in the context of locomotion and the postural control. The number of older individuals is 841 million in 2015, which is four times higher than the 202 million that lived in 1950. Aging causes many motor, sensorial and neural deficits, which impair locomotion and postural control in the elderly. The severity of this framework is worsened when the aging goes along with a movement disorder, such as Parkinson disease, Chorea, Dystonia, Huntington disease, etc. Therefore, the aim of this book is to highlight the influence of different aspects on planning, controlling and performing locomotion and posture tasks. In attempting to improve current knowledge in this field, invited authors present and discuss how environmental, sensorial, motor, cognitive and individual aspects influence the planning and performance of locomotor and postural activities. The major thrust of the book is to address the mechanisms involved in controlling and planning motor action in neurological healthy individuals, as well as in those who suffer from movement disorders or face the effects of aging, indicating the aspects that impair locomotion and postural control. In addition, new technologies, tools and interventions designed to manage the effects of aging and movement disorders are presented in the book.

A large number of volumes have been produced summarizing the work on generation and control of rhythmic movements, in particular locomotion. Unfortunately most of them focus on locomotor studies done on animals. This edited volume redresses that imbalance by focusing completely on human locomotor behaviour. The very nature of the problem has both necessitated and attracted researchers from a wide variety of disciplines ranging from psychology, neurophysiology, kinesiology, engineering, medicine to computer science. The different and unique perspectives they bring to this problem provide a comprehensive picture of the current state of knowledge on the generation and regulation of human locomotor behaviour. A common unifying theme of this volume is studying the adaptability of human gait to obtain insights into the control of locomotion. The intentional focus on "adaptability" is meant to draw attention to the importance of understanding the generation and regulation of "skilled locomotor behaviour" rather than just the generation of basic locomotor patterns which has been the major focus of animal studies. The synthesis chapter at the end of the volume examines how the questions posed, the technology, and the experimental and theoretical paradigms have evolved over the years, and what the future has in store for this important research domain.

Since the classic studies of Woodworth (1899), the role of vision in the control of movement has been an important research topic in experimental psychology. While many early studies were concerned with the relative importance of vision and kinesthesis and/or the time it takes to use visual information, recent theoretical and technical developments have stimulated scientists to ask questions about how different sources of visual information contribute to motor control in different contexts. In this volume, articles are presented that provide a broad coverage of the current research and theory on vision and human motor learning and control. Many of the contributors are colleagues that have met over the years at the meetings and conferences concerned with human movement. They represent a wide range of affiliation and background including kinesiology, physical education, neurophysiology, cognitive psychology and neuropsychology. Thus the topic of vision and motor control is addressed from a number of different perspectives. In general, each author sets an empirical and theoretical framework for their topic, and then discusses current work from their own laboratory, and how it fits into the larger context. A synthesis chapter at the end of the volume identifies commonalities in the work and suggests directions for future experimentation.