Influence of vision on adaptive postural responses following standing on an incline

Earhart, Gammon M.; Henckens, Josée M.; Carlson‐Kuhta, Patricia; Horak, Fay B.

doi:10.1007/s00221-010-2208-4

Cited by 17 publications

(8 citation statements)

References 16 publications

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“…The frequency of responders and the nature of their aftereffect profile (first-order and linear sway trajectory) are comparable to previous findings ( Kluzik et al, 2005 ; Chong et al, 2014 ). These findings are consistent with previous work, in that the adaptation of the sensorimotor set is an obligatory neural process that is difficult to hasten or overcome without vision or cognitive provisions ( Teasdale et al, 1991 ; Kluzik et al, 2007 ; Earhart et al, 2010 ). Although postural control requires some executive control, it is not fully amenable to volition ( Chong et al, 1999 , 2000 ).…”

Section: Discussionsupporting

confidence: 92%

“…Upright posture was temporarily restored when participants’ blindfolds were removed, but the aftereffect resumed its influence when vision was again taken out. In some cases, the magnitude of postural lean increased more than in participants who remained blindfolded throughout testing ( Earhart et al, 2010 ). These studies suggest that the aftereffect, which reflects the newly configured sensorimotor set is difficult to overcome.…”

Section: Introductionmentioning

confidence: 99%

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Two Mechanisms of Sensorimotor Set Adaptation to Inclined Stance

Lee¹,

Baksh

Bryant

et al. 2017

Front. Hum. Neurosci.

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Orientation of posture relative to the environment depends on the contributions from the somatosensory, vestibular, and visual systems mixed in varying proportions to produce a sensorimotor set. Here, we probed the sensorimotor set composition using a postural adaptation task in which healthy adults stood on an inclined surface for 3 min. Upon returning to a horizontal surface, participants displayed a range of postural orientations – from an aftereffect that consisted of a large forward postural lean to an upright stance with little or no aftereffect. It has been hypothesized that the post-incline postural change depends on each individual’s sensorimotor set: whether the set was dominated by the somatosensory or vestibular system: Somatosensory dominance would cause the lean aftereffect whereas vestibular dominance should steer stance posture toward upright orientation. We investigated the individuals who displayed somatosensory dominance by manipulating their attention to spatial orientation. We introduced a distraction condition in which subjects concurrently performed a difficult arithmetic subtraction task. This manipulation altered the time course of their post-incline aftereffect. When not distracted, participants returned to upright stance within the 3-min period. However, they continued leaning forward when distracted. These results suggest that the mechanism of sensorimotor set adaptation to inclined stance comprises at least two components. The first component reflects the dominant contribution from the somatosensory system. Since the postural lean was observed among these subjects even when they were not distracted, it suggests that the aftereffect is difficult to overcome. The second component includes a covert attentional component which manifests as the dissipation of the aftereffect and the return of posture to upright orientation.

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Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Two Mechanisms of Sensorimotor Set Adaptation to Inclined Stance

Lee¹,

Baksh

Bryant

et al. 2017

Front. Hum. Neurosci.

View full text Add to dashboard Cite

show abstract

“…The direction and amplitude of the after-effect were related to the direction and amplitude of the incline and brief periods of vision only temporarily suppressed the response (Earhart et al 2010). They concluded that the leaning after-effect results from an adaptive change to the set point for postural control and that the central nervous system regulates posture through control of whole-body variables.…”

Section: Introductionmentioning

confidence: 99%

Podokinetic stimulation causes shifts in perception of straight ahead

et al. 2010

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Podokinetic after-rotation (PKAR) is a phenomenon in which subjects inadvertently rotate when instructed to step in place after a period of walking on a rotating treadmill. PKAR has been shown to transfer between different forms of locomotion, but has not been tested in a non-locomotor task. We conducted two experiments to assess effects of PKAR on perception of subjective straight ahead and on quiet standing posture. Twenty-one healthy young right-handed subjects pointed to what they perceived as their subjective straight ahead with a laser pointer while they were recorded by a motion capture system both before and after a training period on the rotating treadmill. Subjects performed the pointing task while standing, sitting on a chair without a back, and a chair with a back. After the training period, subjects demonstrated a significant shift in subjective straight ahead, pointing an average of 29.1 ± 10.6 degrees off of center. The effect was direction-specific, depending on whether subjects had trained in the clockwise or counter-clockwise direction. Postures that limited subjects’ ability to rotate the body in space resulted in reduction, but not elimination, of the effect. The effect was present in quiet standing and even in sitting postures where locomotion was not possible. The robust transfer of PKAR to non-locomotor tasks, and across locomotor forms as demonstrated previously, is in contrast to split-belt adaptations that show limited transfer. We propose that, unlike split-belt adaptations, podokinetic adaptations are mediated at supraspinal, spatial orientation areas that influences spinal-level circuits for locomotion.

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“…Some control subjects in our study did show the aftereffect (58%), which is a reliable comparison to previous studies in healthy and Parkinson's disease populations. 6,16 The finding that all subjects in the Vestibular group displayed the lean aftereffect may reflect a decrease in the flexibility of the sensory integration mechanisms. 15 This adaptation may be the same resetting of the surface-reference point mentioned by Kluzik and colleagues.…”

Section: Discussionmentioning

confidence: 98%

“…By removing the visual component during the inclined stance protocol, we were able to test the extent of somatosensory dominance in our subjects. 6,16 The finding that all subjects in the Vestibular group displayed the lean aftereffect may reflect a decrease in the flexibility of the sensory integration mechanisms. 17 It is not entirely clear, however, whether this apparent preference toward a more influential somatosensory integration in the vestibular group indicates increased sensitivity to somatosensory cues.…”

Section: Discussionmentioning

confidence: 98%