graviceptive

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...

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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...

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...

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...

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...

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...

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...

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...

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...

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)...

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...

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...

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...

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...

Perception of verticality is essential for postural control. On the other hand, postural instability is one of the cardinal features in Parkinson's disease (PD). Thus, the objective of this study was to evaluate the vertical perception using the subjective visual vertical test in PD patients with different degrees of postural instability and in different stages of disease. Forty five idiopathic PD patients were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS), the Hoehn and Yahr Scale, the clinical test for postural instability, and the subjective visual vertical test...

BACKGROUND AND PURPOSE: There is little evidence about the site where compensatory vestibular mechanisms in patients with cerebellar strokes take place. METHODS: To determine whether the location of a cerebellar lesion might be a crucial variable in vestibular compensation a sample of 22 patients with cerebellar stroke were tested for graviceptive function in the acute and chronic stage. RESULTS: Our statistical anatomical lesion analysis indicated that mainly lesions of the cerebellar hemispheres (lobule V, VI, VIIa) hinder vestibular compensation and might lead to an overcompensation...

Gravitropism, the slow reorientation of plant growth in response to gravity, is a major determinant of the form and posture of land plants. Recently a universal model of shoot gravitropism, the AC model, was presented, in which the dynamics of the tropic movement is only determined by the conflicting controls of (1) graviception that tends to curve the plants toward the vertical, and (2) proprioception that tends to keep the stem straight. This model was found to be valid for many species and over two orders of magnitude of organ size...

Developmental and evolutionary data from vertebrates are beginning to elucidate the origin of the sensorimotor pathway that links gravity and motion detection to image-stabilizing eye movements--the vestibulo-ocular reflex (VOR). Conserved transcription factors coordinate the development of the vertebrate ear into three functional sensory compartments (graviception/translational linear acceleration, angular acceleration and sound perception). These sensory components connect to specific populations of vestibular and auditory projection neurons in the dorsal hindbrain through undetermined molecular mechanisms...

Tactile stimuli provide animals with important information about the environment, including physical features such as obstacles, and biologically relevant cues related to food, mates, hosts and predators. The antennae, the principal sensory organs of insects, house an array of sensory receptors for olfaction, gustation, audition, nociception, balance, stability, graviception, static electric fields, and thermo-, hygro- and mechanoreception. The antennae, being the anteriormost sensory appendages, play a prominent role in social interactions with conspecifics that involve primarily chemosensory and tactile stimuli...