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Shigehiko Ogoh, Michaël Marais, Romain Lericollais, Pierre Denise, Peter B Raven, Hervé Normand
The aim of the present study was to assess carotid baroreflex (CBR) during acute changes in otolithic activity in humans. To address this question, we designed a set of experiments to identify the modulatory effects of microgravity on CBR function at a tilt angle of -2{degree sign}, which was identified to minimize changes in central blood volume during parabolic flight. During parabolic flight at 0g and 1g, CBR function curves were modelled from the heart rate (HR) and mean arterial pressure (MAP) responses to rapid pulse trains of neck pressure (NP) and neck suction (NS) ranging from +40 to -80 Torr; CBR control of HR (carotid-HR) and MAP (carotid-MAP) baroreflex function curves, respectively...
May 10, 2018: Journal of Applied Physiology
Renaud Bastien, Olivia Guayasamin, Stéphane Douady, Bruno Moulia
To grow straight and upright, plants need to regulate actively their posture. Gravitropic movement, which occurs when plants modify their growth and curvature to orient their aerial organ against the force of gravity, is a major feature of this postural control. A recent model has shown that graviception and proprioception are sufficient to account for the gravitropic movement and subsequent organ posture demonstrated by a range of species. However, some plants, including wheat coleoptiles, exhibit a stronger regulation of posture than predicted by the model...
2018: PloS One
Roman Goulard, Jean-Louis Vercher, Stéphane Viollet
To avoid crashing onto the floor, a free falling fly needs to trigger its wingbeats quickly and control the orientation of its thrust accurately and swiftly to stabilize its pitch and hence its speed. Behavioural data have suggested that the vertical optic flow produced by the fall and crossing the visual field plays a key role in this anti-crash response. Free fall behavior analyses have also suggested that flying insect may not rely on graviception to stabilize their flight. Based on these two assumptions, we have developed a model which accounts for hoverflies´ position and pitch orientation recorded in 3D with a fast stereo camera during experimental free falls...
January 2018: PLoS Computational Biology
Fabien Cignetti, Pierre-Yves Chabeauti, Jasmine Menant, Jean-Luc J J Anton, Christina Schmitz, Marianne Vaugoyeau, Christine Assaiante
The present study investigated the cortical areas engaged in the perception of graviceptive information embedded in biological motion (BM). To this end, functional magnetic resonance imaging was used to assess the cortical areas active during the observation of human movements performed under normogravity and microgravity (parabolic flight). Movements were defined by motion cues alone using point-light displays. We found that gravity modulated the activation of a restricted set of regions of the network subtending BM perception, including form-from-motion areas of the visual system (kinetic occipital region, lingual gyrus, cuneus) and motor-related areas (primary motor and somatosensory cortices)...
2017: Frontiers in Psychology
Guillaume P Dugué, Matthieu Tihy, Boris Gourévitch, Clément Léna
Head movements are primarily sensed in a reference frame tied to the head, yet they are used to calculate self-orientation relative to the world. This requires to re-encode head kinematic signals into a reference frame anchored to earth-centered landmarks such as gravity, through computations whose neuronal substrate remains to be determined. Here, we studied the encoding of self-generated head movements in the rat caudal cerebellar vermis, an area essential for graviceptive functions. We found that, contrarily to peripheral vestibular inputs, most Purkinje cells exhibited a mixed sensitivity to head rotational and gravitational information and were differentially modulated by active and passive movements...
June 13, 2017: ELife
Ai Hosaka, Ryoya Tsunoda, Tetsuto Yamaguchi, Yasuro Shibagaki
Body lateropulsion is known to be caused commonly by lateral medullary lesions but rarely by pontine lesions. It is also known to be associated with lesions of the dorsal spinothalamic tract or ascending graviceptive pathways. We herein report the case of a 75-year-old woman presenting with contralateral lateropulsion and cerebellar tremor caused by pons infarction. To our knowledge, this is the first case report of pontine infarction causing both lateropulsion and cerebellar tremor. Our case may be helpful in anatomical studies of ascending graviceptive pathways...
2017: Internal Medicine
Kirsten Platho-Elwischger, Gottfried Kranz, Thomas Sycha, Daniela Dunkler, Paulus Rommer, Christian Mueller, Eduard Auff, Gerald Wiest
No abstract text is available yet for this article.
February 15, 2017: Journal of the Neurological Sciences
Christoph Helmchen, Jan-Birger Kirchhoff, Martin Göttlich, Andreas Sprenger
BACKGROUND: The cerebellum integrates proprioceptive, vestibular and visual signals for postural control. Cerebellar patients with downbeat nystagmus (DBN) complain of unsteadiness of stance and gait as well as blurred vision and oscillopsia. OBJECTIVES: The aim of this study was to elucidate the differential role of visual input, gaze eccentricity, vestibular and proprioceptive input on the postural stability in a large cohort of cerebellar patients with DBN, in comparison to healthy age-matched control subjects...
2017: PloS One
Sandra Becker-Bense, Hans-Georg Buchholz, Bernhard Baier, Mathias Schreckenberger, Peter Bartenstein, Andreas Zwergal, Thomas Brandt, Marianne Dieterich
The aim of the study was to uncover mechanisms of central compensation of vestibular function at brainstem, cerebellar, and cortical levels in patients with acute unilateral midbrain infarctions presenting with an acute vestibular tone imbalance. Eight out of 17 patients with unilateral midbrain infarctions were selected on the basis of signs of a vestibular tone imbalance, e.g., graviceptive (tilts of perceived verticality) and oculomotor dysfunction (skew deviation, ocular torsion) in F18-fluordeoxyglucose (FDG)-PET at two time points: A) in the acute stage, and B) after recovery 6 months later...
2016: PloS One
Laure Mathevon, Nicolas Leroux, Céline Piscicelli, Emmanuelle Clarac, Shenhao Dai, Patrice Davoine, Paul Krack, Dominic Perennou
OBJECTIVE: To take care of postural disorders is a major issue in Parkinson's disease (PD). We present a documented observation suggesting the existence of a biased representation of verticality in PD, resulting in a severe retropulsion and recurrent falls. A rehabilitation program aimed to modulate verticality perception dramatically improved the postural perception of the vertical, trunk posture and balance abilities, and reduced retropulsion as well as lastingly fall frequency. OBSERVATIONS: A 68 year-old patient with Parkinson's disease fall backward 3 times a day...
September 2016: Annals of Physical and Rehabilitation Medicine
Fay B Horak, JoAnn Kluzik, Frantisek Hlavacka
Vestibular information is known to be important for postural stability on tilting surfaces, but the relative importance of vestibular information across a wide range of surface tilt velocities is less clear. We compared how tilt velocity influences postural orientation and stability in nine subjects with bilateral vestibular loss and nine age-matched, control subjects. Subjects stood on a force platform that tilted 6 deg, toes-up at eight velocities (0.25 to 32 deg/s), with and without vision. Results showed that visual information effectively compensated for lack of vestibular information at all tilt velocities...
September 1, 2016: Journal of Neurophysiology
A Drakul, C J Bockisch, A A Tarnutzer
The visual line bisection task (LBT) is sensitive to perceptual biases of visuospatial attention, showing slight leftward (for horizontal lines) and upward (for vertical lines) errors in healthy subjects. It may be solved in an egocentric or allocentric reference frame, and there is no obvious need for graviceptive input. However, for other visual line adjustments, such as the subjective visual vertical, otolith input is integrated. We hypothesized that graviceptive input is incorporated when performing the LBT and predicted reduced accuracy and precision when roll-tilted...
August 1, 2016: Journal of Neurophysiology
Bruna Antinori Vignola da Fonseca, Cristiana Borges Pereira, Frederico Jorge, Renata Simm, Samira Apostolos-Pereira, Dagoberto Callegaro
The purpose of this study was to determine the relationship between perception of verticality and balance disorders in multiple sclerosis patients. We evaluated patients and healthy controls. Patients were divided into two groups according to their risk of fall, with or without risk of fall, measured by a Dynamic Gait Index scale. Graviceptive perception was assessed using the subjective visual vertical test. Patients with risk of fall showed worse perception than those without risk of fall, p < 0.001. Misperception of verticality was correlated with the dynamic gait index scores (p < 0...
February 2016: Arquivos de Neuro-psiquiatria
Arne Tribukait, Ola Eiken
The primary aim of this study was to establish whether the decline of the memory of an angular displacement, detected by the semicircular canals, is best characterized by an exponential function or by a power function. In 27 subjects a conflict was created between the semicircular canals and the graviceptive systems. Subjects were seated, facing forwards, in the gondola of a large centrifuge. The centrifuge was accelerated from stationary to 2.5Gz. While the swing out of the gondola (66°) during acceleration constitutes a frontal plane angular-displacement stimulus to the semicircular canals, the graviceptive systems persistently signal that the subject is upright...
February 2016: Cognitive Neurodynamics
Bernhard Baier, Julian Conrad, Thomas Stephan, Valerie Kirsch, Thomas Vogt, Janine Wilting, Wibke Müller-Forell, Marianne Dieterich
OBJECTIVE: To determine whether there are distinct thalamic regions statistically associated with either contraversive or ipsiversive disturbance of verticality perception measured by subjective visual vertical (SVV). METHODS: We used modern statistical lesion behavior mapping on a sample of 37 stroke patients with isolated thalamic lesions to clarify which thalamic regions are involved in graviceptive otolith processing and whether there are distinct regions associated with contraversive or ipsiversive SVV deviation...
January 12, 2016: Neurology
Bernhard Baier, Thomas Vogt, Franziska Rohde, Hannah Cuvenhaus, Julian Conrad, Marianne Dieterich
Based on animal studies, it has been shown that the nucleus ventralis intermedius (VIM) of the thalamus plays an important role within the vestibular system. A few human studies support the vestibular role of the VIM. In this study, we aimed to test the hypothesis whether changing the stimulation status in patients with unilateral deep brain stimulation in the VIM causally modulates the vestibular system, i.e., the graviceptive vertical perception. We tested six tremor patients for tilt of subjective visual vertical (SVV) with unilateral DBS in the VIM (mean age 67 years; mean time since electrode implantation 55 months)...
January 2017: Brain Structure & Function
Mohamed R Habib, Azza H Mohamed, Gamalat Y Osman, Ahmed T Sharaf El-Din, Hanan S Mossalem, Nadia Delgado, Grace Torres, Solymar Rolón-Martínez, Mark W Miller, Roger P Croll
Histamine appears to be an important transmitter throughout the Animal Kingdom. Gastropods, in particular, have been used in numerous studies establishing potential roles for this biogenic amine in the nervous system and showing its involvement in the generation of diverse behaviours. And yet, the distribution of histamine has only previously been described in a small number of molluscan species. The present study examined the localization of histamine-like immunoreactivity in the central and peripheral nervous systems of pulmonate snails of the genus Biomphalaria...
2015: PloS One
Jun-Hyun Kim, Saeromi Kim, Dong Hyun Lee, Tae-Kyeong Lee, Ki-Bum Sung
The isolated body lateropulsion has been well recognized in caudal lateral medullary infarction and postulated to result from the involvement of ipsilateral dorsal spinocerebellar tract which is known to convey proprioception of trunk and legs. However, there has been no case accompanied by the tilt of the subjective visual vertical in caudal lateral medullary infarction. Recently, it has been suggested that a lesion in the ipsilateral graviceptive vestibulothalamic pathway can lead to alteration of subjective visual vertical without ocular tilt reaction in various brainstem lesions...
2015: Journal of Vestibular Research: Equilibrium & Orientation
Alexander A Tarnutzer, Werner Wichmann, Dominik Straumann, Christopher J Bockisch
Current concepts postulate a decisive role of the cerebellar nodulus in the processing of otolith input. We hypothesized that nodular lesions abolish otolith-perceptual integration, predicting alignment of perceived direction of earth vertical with the z-axis of the head and not with gravity. In an 80-year-old patient with acute heminodular infarction, the subjective visual vertical deviated contralesionally by -21.1° when the patient was upright. After subtracting this offset, perceived vertical closely matched the patient's head orientation when the patient was roll-tilted...
February 2015: Annals of Neurology
Doris-Eva Bamiou, Borka Ceranic, Deborah Vickers, Ewa Zamyslowska-Szmytke, Robin Cox, Philip Chadwick, Linda M Luxon
Low-level radiofrequency (RF) signals may produce disorientation and nausea. In experiment I, we assessed mobile phone effects on graviception in nine symptomatic subjects after mobile telephone use and 21 controls. The mobile handset was strapped to each ear for 30 min in pulsed emission, continuous RF emission, or no emission test mode, respectively. The subjective visual vertical and horizontal (SVV/SVH) were tested from min 25 of exposure. There was no exposure effect; however, there was an ear effect, with the SVV/SVH being shifted to the opposite direction of the ear exposed...
January 2015: Bioelectromagnetics
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