The role of vestibular and somatosensory systems in intersegmental control of upright stance

Creath, Rob; Kiemel, Tim; Horak, Fay B.; Jeka, John J.

doi:10.3233/ves-2008-18104

Cited by 54 publications

(7 citation statements)

References 35 publications

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“…Semicircular ducts monitor head rotation and are lled with a uid called endolymph, whose viscosity affects function and depends on body temperature 32,33 . Head motion proprioception is essential for navigation 29 , balance 41 , vision 28 , motor coordination 30 , and spatial awareness 31 . Therefore, the SDS is expected to attune to the spectrum of head rotations experienced by an organism 36 .…”

mentioning

confidence: 99%

Inner ear biomechanics reveals a Late Triassic origin for mammalian endothermy

Araújo

David

Benoît

et al. 2022

Nature

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Endothermy ("warm-bloodedness") underpins the ecological dominance of mammals and birds in diverse environmental settings^1-3. However, it is unclear when this crucial feature emerged during mammalian evolutionary history, as most fossil evidence is ambiguous^4-25. Here, we show that new information on this key evolutionary transition can be obtained from the morphology of the endolymph-lled semicircular ducts of the inner ear that monitor head rotations and are essential for motor coordination, navigation, and spatial awareness^26-31. Increased body temperature during the ectotherm-endotherm transition of mammal ancestors would decrease endolymph viscosity, negatively impacting the biomechanics of the semicircular ducts^32,33, while simultaneously increasing activity levels^34,35 required improved performance^36. Speci c morphological changes to the membranous ducts and enclosing bony canals were, therefore, necessary to maintain optimal functionality. We track these morphological changes in 341 vertebrates, including 56 extinct synapsids, and show that canals with relatively thin cross-sections and small radii of curvature are indicative of mammalian endothermy. This inner ear morphotype evolved abruptly ~233 million years ago, during the Late Triassic, in Mammaliamorpha. Our conclusion differs from previous suggestions3-17, and we interpret most stem-mammals as ectotherms. Endothermy as a crucial physiological characteristic joins other distinctive mammalian features that arose during this period of climatic instability^37-39. *Ricardo Araújo and Romain David contributed equally to this work. Main TextEndotherms can maintain high and nearly constant body temperature through metabolic heat production, allowing them to optimize chemical reactions and sustain aerobic activity for long periods of time while remaining relatively independent from external conditions 1,2,40 . Compared to ectotherms, endotherms are more active, travel farther, and achieve higher locomotor speeds, all at the expense of higher energy costs 34,35 (Supplementary Data 1). Consequently, extant mammals and birds occupy a variety of ecological niches unrivalled by other vertebrates. Endothermy is a quintessentially mammalian feature, intimately related to other hallmarks such as lactation, sweat glands and fur 2,3 . However, its evolution remains one of the great unsolved mysteries of palaeontology 2,3 . Lines of evidence invoked to identify the emergence of mammalian endothermy rely mostly on skeletal anatomical features, but also on ichnological, histological and isotopic information, which have been used as correlates for aerobic

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confidence: 99%

Inner ear biomechanics reveals a Late Triassic origin for mammalian endothermy

Araújo

David

Benoît

et al. 2022

Nature

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“…A light touch is a potent stabilising stimulus, able to replace vision in subjects with impaired vestibular system (132)(133)(134).…”

Section: Touchmentioning

confidence: 99%

Specific Posture-Stabilising Effects of Vision and Touch Are Revealed by Distinct Changes of Body Oscillation Frequencies

2021

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We addressed postural instability during stance with eyes closed (EC) on a compliant surface in healthy young people. Spectral analysis of the centre of foot pressure oscillations was used to identify the effects of haptic information (light-touch, EC-LT), or vision (eyes open, EO), or both (EO-LT). Spectral median frequency was strongly reduced by EO and EO-LT, while spectral amplitude was reduced by all “stabilising” sensory conditions. Reduction in spectrum level by EO mainly appeared in the high-frequency range. Reduction by LT was much larger than that induced by the vision in the low-frequency range, less so in the high-frequency range. Touch and vision together produced a fall in spectral amplitude across all windows, more so in anteroposterior (AP) direction. Lowermost frequencies contributed poorly to geometric measures (sway path and area) for all sensory conditions. The same subjects participated in control experiments on a solid base of support. Median frequency and amplitude of the spectrum and geometric measures were largely smaller when standing on solid than on foam base but poorly affected by the sensory conditions. Frequency analysis but not geometric measures allowed to disclose unique tuning of the postural control mode by haptic and visual information. During standing on foam, the vision did not reduce low-frequency oscillations, while touch diminished the entire spectrum, except for the medium-high frequencies, as if sway reduction by touch would rely on rapid balance corrections. The combination of frequency analysis with sensory conditions is a promising approach to explore altered postural mechanisms and prospective interventions in subjects with central or peripheral nervous system disorders.

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“…An inventory of all responsible receptors is implausible. One can only hope to itemise most of those for which reports are available, based on experiments conducted in quiet and perturbed stance conditions (Borel et al, 2008;Creath et al, 2008;Pettorossi and Schieppati, 2014;Cheung and Schmuckler, 2021;Nedelkou et al, 2021). In the same vein, it is virtually impossible to indicate all the muscles more or less active when standing on a compliant surface or under similarly critical postures, such as standing in tandem or on one leg.…”

Section: Introductionmentioning

confidence: 99%

Balance Adaptation While Standing on a Compliant Base Depends on the Current Sensory Condition in Healthy Young Adults

Sozzi

Schieppati

2022

Front. Hum. Neurosci.

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BackgroundSeveral investigations have addressed the process of balance adaptation to external perturbations. The adaptation during unperturbed stance has received little attention. Further, whether the current sensory conditions affect the adaptation rate has not been established. We have addressed the role of vision and haptic feedback on adaptation while standing on foam.MethodsIn 22 young subjects, the analysis of geometric (path length and sway area) and spectral variables (median frequency and mean level of both total spectrum and selected frequency windows) of the oscillation of the centre of feet pressure (CoP) identified the effects of vision, light-touch (LT) or both in the anteroposterior (AP) and mediolateral (ML) direction over 8 consecutive 90 s standing trials.ResultsAdaptation was obvious without vision (eyes closed; EC) and tenuous with vision (eyes open; EO). With trial repetition, path length and median frequency diminished with EC (p < 0.001) while sway area and mean level of the spectrum increased (p < 0.001). The low- and high-frequency range of the spectrum increased and decreased in AP and ML directions, respectively. Touch compared to no-touch enhanced the rate of increase of the low-frequency power (p < 0.05). Spectral differences in distinct sensory conditions persisted after adaptation.ConclusionBalance adaptation occurs during standing on foam. Adaptation leads to a progressive increase in the amplitude of the lowest frequencies of the spectrum and a concurrent decrease in the high-frequency range. Within this common behaviour, touch adds to its stabilising action a modest effect on the adaptation rate. Stabilisation is improved by favouring slow oscillations at the expense of sway minimisation. These findings are preliminary to investigations of balance problems in persons with sensory deficits, ageing, and peripheral or central nervous lesion.

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The role of vestibular and somatosensory systems in intersegmental control of upright stance

Cited by 54 publications

References 35 publications

Inner ear biomechanics reveals a Late Triassic origin for mammalian endothermy

Inner ear biomechanics reveals a Late Triassic origin for mammalian endothermy

Specific Posture-Stabilising Effects of Vision and Touch Are Revealed by Distinct Changes of Body Oscillation Frequencies

Balance Adaptation While Standing on a Compliant Base Depends on the Current Sensory Condition in Healthy Young Adults

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