Sensory re-weighting in human postural control during moving-scene perturbations

Mahboobin, Arash; Loughlin, Patrick J.; Redfern, Mark S.; Sparto, Patrick J.

doi:10.1007/s00221-005-0053-7

Cited by 89 publications

(68 citation statements)

References 35 publications

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“…Because the optic flow moved in the AP direction, the predominant direction of sway was AP. Since 99% of the power of sway is below 1.5 Hz in similar studies conducted in our lab, the head AP position signal for each 45 s trial was filtered with a 2 nd order lowpass digital Butterworth filter with cutoff frequency 2 Hz in the forward and backward directions [13]. The resulting signal was then differentiated to obtain the velocity of head movement.…”

Section: Data Collection and Analysismentioning

confidence: 99%

“…Analysis was thus limited to the 15 s preceding and 15 s following each transition in Condition 3 ( Figure 2). Based on visual inspection of the current data, as well as previous work in which changes in peak sway velocity due to sudden visual perturbations occurred in less than 5 s [13], we further subdivided the velocity power signals into 5 s intervals that formed the basis of the statistical analysis ( Figure 2). The average power of head sway velocity (P vel ) was computed for each of the 5 s intervals across all nine trials.…”

Section: Data Collection and Analysismentioning

confidence: 99%

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Postural adaptations to repeated optic flow stimulation in older adults

et al. 2008

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The purpose of this study is to understand the processes of adaptation (changes in within-trial postural responses) and habituation (reductions in between-trial postural responses) to visual cues in older and young adults. Of particular interest were responses to sudden increases in optic flow magnitude. The postural sway of 25 healthy young adults and 24 healthy older adults was measured while subjects viewed anterior-posterior 0.4 Hz sinusoidal optic flow for 45 s. Three trials for each of three conditions were performed: 1) constant 12 cm optic flow amplitude (24 cm peak-to-peak), 2) constant 4 cm amplitude (8 cm p-t-p), and 3) a transition in amplitude from 4 to 12 cm. The average power of head sway velocity (P vel ) was calculated for consecutive 5 s intervals during the trial to examine the changes in sway within and between trials. A mixed factor repeated measures ANOVA was performed to examine the effects of subject Group, Trial, and Interval on the P vel . P vel was greater in older adults in all conditions (p < 0.001). During the 12 cm constant amplitude trials, within-trial adaptation occurred for all subjects, but there were differences in the between-trial habituation. P vel of the older adults decreased significantly between all 3 trials, but decreased only between trial 1 and 2 in young adults. While the responses of the young adults to the transition in optic flow from 4 to 12 cm did not significantly change, older adults had an increase in P vel following the transition, ranging from 6.5 dB for the first trial to 3.4 dB for the third trial. These results show that older adults can habituate to repeated visual perturbation exposures; however, this habituation requires a greater number of exposures than young adults. This suggests aging impacts the ability to quickly modify the relative weighting of the sensory feedback for postural stabilization.

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Section: Data Collection and Analysismentioning

confidence: 99%

Section: Data Collection and Analysismentioning

confidence: 99%

Postural adaptations to repeated optic flow stimulation in older adults

et al. 2008

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“…In instances of visual field motion on the other hand, the visual system incorrectly signals self-motion and, therefore, the weight assigned to the visual channel needs to be reduced in order to preserve balance. Following a period of sensory ambiguity and subsequent downweighting of the affected channel, the sensorimotor system requires time to adapt to the reinsertion of reliable sensory information (Jeka et al 2008;Mahboobin et al 2005). Once accurate information is restored, the involved channel is upweighted leading to an imbalance of weights, which results in excessive postural sway.…”

Section: Introductionmentioning

confidence: 99%

Age-dependent modulation of sensory reweighting for controlling posture in a dynamic virtual environment

Eikema

Hatzitaki

Tzovaras

et al. 2011

AGE

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Older adults require more time to reweight sensory information for maintaining balance that could potentially lead to increased incidence of falling in rapidly changing or cognitively demanding environments. In this study, we manipulated the visual surround information during a collision avoidance task in order to investigate how young and elderly adults engage in sensory reweighting under conditions of visual anticipation. Sixteen healthy elderly (age: 71.5±4.9 years; height: 159.3±6.6 cm; mass: 73.3±3.3 kg) and 20 young (age: 22.8±3.3 years; height: 174.4±10.7 cm; mass: 70.1±13.9 kg) participants stood for 240 s on a force platform under two experimental conditions: quiet standing and standing while anticipating randomly approaching virtual objects to be avoided. During both tasks, the visual surround changed every 60 s from a stationary virtual scene (room) to either a moving room or darkness and then back to a stationary scene to evoke sensory reweighting processes. In quiet standing, elderly showed greater sway variability and were more severely affected by the removal or degradation of visual surround information when compared to young participants. During visual anticipation, sway variability was not different between the age groups. In addition, both young and elderly participants were similarly affected by the degradation or removal of the visual surround. These findings suggest that sensory reweighting in a dynamic virtual environment that evokes visual anticipation interacts with postural state anxiety regardless of age. Elderly show less efficient sensory reweighting in quiet standing due to greater visual field dependence possibly associated with fear of falling.

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“…Other examples of sensory weighting are the sense of location of body parts in the peripersonal space (Bremner et al, 2008) and integration of visual and haptic feedback during grasping tasks (Säfström and Edin, 2004). During balance control humans weight sensory input from the vestibular system, mechanoreceptors, and vision (van der Kooij et al, 2001;Zupan et al, 2002;Mahboobin et al, 2005). Changes in environmental properties bring about changes in the relative weights between information channels: sensory reweighting (Peterka, 2002;Peterka and Loughlin, 2004).…”

Section: Introductionmentioning

confidence: 99%

Sensory Weighting of Force and Position Feedback in Human Motor Control Tasks

Mugge¹,

Schuurmans²,

Schouten³

et al. 2009

J. Neurosci.

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In daily life humans integrate force and position feedback from mechanoreceptors, proprioception, and vision. With handling relatively soft, elastic objects, force and position are related and can be integrated to improve the accuracy of an estimate of either one. Sensory weighting between different sensory systems (e.g., vision and proprioception) has been extensively studied. This study investigated whether similar weighting can be found within the proprioceptive sensory system, more specifically between the modalities force and position. We hypothesized that sensory weighting is governed by object stiffness: position feedback is weighted heavier on soft objects (large deflections), while force feedback is weighted heavier on stiff objects (small deflections). Subjects were instructed to blindly reproduce either position or force while holding a one degree of freedom haptic manipulator that simulated a linear spring with one of four predetermined stiffnesses. In catch trials the spring was covertly replaced by a nonlinear spring. The difference in force (⌬F) and position (⌬X) between the regular and the catch trials revealed the sensory weighting between force and position feedback. A maximum likelihood estimation model predicted that: (1) task instruction did not affect the outcome measures, and (2) force feedback is weighted heavier with increasing object stiffness as was hypothesized. Both effects were found experimentally, and the subjects' sensory weighting closely resembled the optimal model predictions. To conclude, this study successfully demonstrated sensory weighting within the proprioceptive system.

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Sensory re-weighting in human postural control during moving-scene perturbations

Cited by 89 publications

References 35 publications

Postural adaptations to repeated optic flow stimulation in older adults

Postural adaptations to repeated optic flow stimulation in older adults

Age-dependent modulation of sensory reweighting for controlling posture in a dynamic virtual environment

Sensory Weighting of Force and Position Feedback in Human Motor Control Tasks

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