Visuomotor Control of Human Adaptive Locomotion: Understanding the Anticipatory Nature

Abstract

To maintain balance during locomotion, the central nervous system (CNS) accommodates changes in the constraints of spatial environment (e.g., existence of an obstacle or changes in the surface properties). Locomotion while modifying the basic movement patterns in response to such constraints is referred to as adaptive locomotion. The most powerful means of ensuring balance during adaptive locomotion is to visually perceive the environmental properties at a distance and modify the movement patterns in an anticipatory manner to avoid perturbation altogether. For this reason, visuomotor control of adaptive locomotion is characterized, at least in part, by its anticipatory nature. The purpose of the present article is to review the relevant studies which revealed the anticipatory nature of the visuomotor control of adaptive locomotion. The anticipatory locomotor adjustments for stationary and changeable environment, as well as the spatio-temporal patterns of gaze behavior to support the anticipatory locomotor adjustments are described. Such description will clearly show that anticipatory locomotor adjustments are initiated when an object of interest (e.g., a goal or obstacle) still exists in far space. This review also show that, as a prerequisite of anticipatory locomotor adjustments, environmental properties are accurately perceived from a distance in relation to individual’s action capabilities.

“Walking” through the sensory, cognitive, and temporal degradations of healthy aging

“…Our daily interaction with the environment requires input from our sensory systems, interpretation and integration of those inputs, and the adoption of a specific response and reaction to a given event. Adaptive behavior, therefore, depends on the appropriate functioning of the receptor—nervous system—effector system . Aging, however, makes our ability to adapt challenging, given that the quality of sensory input declines .…”

“…Age‐associated changes in visual perception (Table ) also lead to various difficulties such as decreased ability to focus on near objects due to hardening of the lens (i.e., presbyopia); blurred vision due to cataracts; changes in color perception, temporal resolution, and motion perception; and a loss of fine detail (high spatial frequency) patterns . Visual function is also affected by factors such as room illumination, altered gaze patterns, and reductions to the visual field, decreased contrast sensitivity, reduced dynamic and binocular visual acuity, and reduced retinal illuminance (i.e., the ability of the pupil to dilate in low illumination), as well as impaired depth perception . Critically, vision provides exteroceptive information about obstacle location and its characteristics, as well as exproprioceptive signals about limb orientation and its position and velocity as one goes over obstacles and is, thus, essential for detecting and avoiding environmental hazards.…”

“…Critically, vision provides exteroceptive information about obstacle location and its characteristics, as well as exproprioceptive signals about limb orientation and its position and velocity as one goes over obstacles and is, thus, essential for detecting and avoiding environmental hazards. However, oculomotor behavior undergoes significant changes as we age, mainly affecting visuomotor processing, which, in turn, influences adaptive locomotion . Specifically, both the latency and the duration of saccades increase, while their accuracy decreases, which, in turn, leads to an increase of the corrective and refixation saccades .…”

Acquiring visual information for locomotion by older adults: A systematic review

“…The importance of different types of visual information for successful locomotion has been established (Higuchi, 2013;Patla, 1997Patla, , 1998Patla and Vickers, 1997). Different kinds of information are required during locomotion for pre-planning (feed-forward), and for on-line control (feedback) (Marigold and Patla, 2007;Patla, 1998Patla, , 2003.…”

Visuo-locomotor coordination for direction changes in a manual wheelchair as compared to biped locomotion in healthy subjects

“…Specifically, it is suggested that these head movements provide an allocentric reference frame to re-orient the body [3] and steer towards the new direction of travel [7]. During adaptive locomotion, common characteristics of gaze behavior show that the majority of fixations are either directed towards a desired future path or an object of interest [4,8]. Moreover, prior to a direction change, individuals invariably make saccadic eye movements towards the end-point of the travel path, which allows the identification and extraction of information concerning the future path [4].…”