Influence of Visual and Haptic Cues on Podokinetic After-Rotation

ABSTRACT

Active countercircling on a rotating platform for 15 min causes individuals to involuntarily circle in the same direction when they step in place on firm ground. This is referred to as podokinetic after-rotation (PKAR). It is unclear how interjecting brief periods of visual or haptic inputs for a stable orientation reference affects PKAR. The authors studied this issue in 16 healthy individuals who participated in three sessions each. Following active countercircling, participants attempted to step in place for 30 min on firm ground. In two of three sessions, participants received full visual input or made fingertip contact with a stationary object for 30 s during 30 min of ongoing PKAR. All participants slowed or stopped rotating during the presence of visual or haptic inputs and resumed PKAR after removal of these inputs. Exponential functions fitted to angular trunk velocity versus time plots revealed no significant differences across conditions (p > .05). The preservation of PKAR after brief exposure to a visual or haptic reference is consistent with a slowly decaying velocity storage that is not reset or dumped after exposure to conflicting visual or haptic cues.     

A New Book by N. A. Bernstein: “On Dexterity and Its Development”

A book, ‘On Dexterity and its Development,’ written by N. A. Bernstein in the 1940s has recently been published in Moscow. We describe briefly the amazing fate of this miraculously saved book and of its famous author. The book is unique in its reader-friendly handling of the most complicated issues of motor control, motor development, motor skill acquisition, and more general aspects of brain activity. It presents the basis for what is now called motor control and for some of the more fundamental issues of theoretical neuroscience. Bernstein described his views on multilevel control of movements, the role of sensory feedback, preprogramming, feedback and feedforward components in motor control, the role of exercise, and other subjects. Despite the fact that the book was written nearly half a century ago, its deep philosophical content remains beyond any competition.     

Interstimulus Intervals and Sensory Modality Modulate the Impact of a Cognitive Task on Postural Control

The present literature not only reveals the use of a wide variety of cognitive tasks but variability in their interaction with postural control. The question then arises, as to, whether postural control is sensitive to specific features of a cognitive task. The present experiment assessed the impact of cognitive tasks with interstimulus intervals (ISI) of varied duration and sensory modality on postural control in young adults. Seventeen participants (23.71 ± 1.99 years old) were instructed to stand on a force platform while concurrently performing cognitive tasks with ISIs of two and 5 s. The tasks were presented both, auditorily and visually. The visual tasks consisted of counting the total occurrence of a single digit. The auditory tasks consisted of counting the total occurrence of a single letter. Performing the cognitive tasks with an ISI of 2 s resulted only in an increase in the anteroposterior mean power frequency. Presenting the tasks visually also significantly reduced area of 95% confidence ellipse and AP and mediolateral sway variability. These results may suggest that ISIs can modify postural performance by altering the allocation of attentional focus. Also, presenting tasks using a visual sensory modality appears to yield lower postural sway.     

Spatial and Temporal Adaptations That Accompany Increasing Catching Performance During Learning

During stance, head extension increases postural sway, possibly due to interference with sensory feedback. The sit-to-stand movement is potentially destabilizing due to the development of momentum as the trunk flexes forward and the body transitions to a smaller base of support. It is unclear what role head orientation plays in the postural and movement characteristics of the sit-to-stand transition. The authors assessed how moving from sitting to standing with head-on-trunk extension compared with moving with the head neutral or flexed, or with moving with the head facing forward in space (which would involve head-on-trunk extension, but not head-in-space extension) in healthy, young participants. Head-on-trunk extension increased center of pressure variability, but decreased movement velocities, movement duration, and trunk flexion compared with flexed and neutral head-on-trunk orientations. Similarities in movement characteristics between head-on-trunk extension and the forward head-in-space orientation suggest that stabilizing the head in space does not fully counteract the postural and movement changes due to head-on-trunk extension. Findings suggest that proprioceptive feedback from the neck muscles contributes to the regulation of posture and movement, and therefore should not be overlooked in research on the role of sensory feedback in postural control.     

The Interrelationships Between Anxiety,Motor Performance and Electromyography

Notterman (1975) argued, contrary to my 1974 article, that the data obtained by Notterman and Page (1962) confirm the important role of proprioception in skilled performance. I argue that these data are in fact ambiguous when it comes to distinguishing the effects of proprioception from those of outflow control.     

Multisensory Information in the Control of Complex Motor Actions

ABSTRACT— For many of the complex motor actions we perform, perceptual information is available from several different senses including vision, touch, hearing, and the vestibular system. Here I discuss the use of multisensory information for the control of motor action in three particular domains: aviation, sports, and driving. It is shown that performers in these domains use information from multiple senses—frequently with beneficial effects on performance but sometimes with dangerous consequences. Applied psychologists have taken advantage of our natural tendency to integrate sensory information by designing multimodal displays that compensate for situations in which information from one or more of our senses is unreliable or is unattended due to distraction.