bluuebunny/crossref_metadata_2025 huggingface dataset:
Blockchain in or as governance? Evolutions in experimentation, social impacts, and prefigurative practice in the blockchain and DAO space
Authors: Jones Kristopher
Published: November 2019

Blockchain has become much more than simply a fintech technology, and is enabling and inspiring new conversations around politics, governance, organization, institutions and power structures. I published an attempt to start a rigorous academic treatment of ideology in the blockchain space through my master’s thesis titled Toward a Political Sociology of Blockchain at Queen’s University. Since then, there have been continued rich discussions around politics and experimentation in line with the ideals of the blockchain movement. Examples include discussion of blockchain governance as a social contract, discussion of social scalability and how this enables us to organize, forums such as etherean.org, and movements such as RadicalxChange.org and the concept of Liberal Radicalism. Some of these movements have been started by similar actors in the blockchain space: Vitalik Buterin of the Ethereum project co-authored the paper on Liberal Radicalism which is deeply intertwined with RadicalxChange and the ethos of decentralization, and Lane Rettig is an Ethereum core developer and launched Etherean.org to be a non-maximalist community-based discussion of social aspects and implications around the emerging technology. While the cryptocurrency markets trended downward throughout 2018, there have been strong social indicators of a more mature system though increased interdisciplinary participation and development around the technology as well as increased interest by the public sector for use cases such as records keeping and identity solutions. I expand upon some of the concepts discussed in my thesis, and provide further evidence for the particular observations based on additional events I attended and took part in through late 2018 and early 2019. Primarily, additional evidence is taken from my attendance at both the ETHDenver and RadicalxChange conferences. I further develop some of the ideas and connections between the community that has emerged around blockchain technology, and the more recent adaptations in the political sphere, as well as implications of new forms of social organization allowed through the use of such technology.
Brain Injury and Later-Life Cognitive Impairment and Neuropathology: The Honolulu-Asia Aging Study
Authors: Chosy E. Julia , Gross Noele , Meyer Marnie , Liu Catherine Y. , Edland Steven D. , Launer Lenore J. , White Lon R.
Published: November 2019

Background:

Findings are inconsistent regarding the role of traumatic head injury in the subsequent development of neurologic outcomes.

Objective:

Examine the relationship between head injury and later cognitive impairment.

Methods:

A sample of 3,123 Japanese-American men was assessed for history of head injury and evaluated for cognitive impairment using the Cognitive Abilities Screening Instrument (CASI). For a subsample of 676 respondents, neuropathologic results from those with and without head injury were compared.

Results:

Although the crude model showed an association between history of head injury and later severe cognitive impairment, the relationship lost significance in the adjusted model (OR = 1.320, CI: 0.90–1.93), regardless of time between injury and impairment. Similar to cognitive impairment, hippocampal sclerosis was observed significantly more in the brains of respondents with a history of head injury in the crude model, but the relationship weakened in the adjusted model (OR = 1.462, CI: 0.68–3.12). After adjustment, decedents with a head injury demonstrated marginally higher brain weight (OR = 1.003, CI: 1.00–1.01).

Conclusion:

We did not find a relationship between head injury and subsequent cognitive decline in this cohort. The neuropathology results also displayed no strong association between history of head injury and specific brain lesions and characteristics. These results support other findings in prospective cohorts. However, they could be influenced by the demographic make-up of the sample (male Japanese-Americans) or by the observation that the majority reported only a single head injury.
Brain Bromine Levels Associated with Alzheimer’s Disease Neuropathology
Authors: Agarwal Puja , Brockman John D. , Wang Yamin , Schneider Julie A. , Morris Martha C.
Published: November 2019

Background:

Bromine is a naturally occurring element that is widely present in the human environment in various chemical forms primarily as flame retardants, pesticides, and water treatments.

Objective:

In this exploratory study, we investigated the association of brain bromine concentrations on Alzheimer’s disease (AD) neuropathology, cerebral infarcts, and Lewy bodies.

Methods:

The study was conducted in 215 deceased participants of the Memory and Aging Project, a clinical-pathologic cohort study. Brain bromine levels were measured using instrumental neutron activation analysis. Multiple brain regions were assessed for diffuse and neuritic plaques, neurofibrillary tangles, cerebral macro-and microinfarcts, and Lewy bodies. Standardized measures of AD pathology (Braak, CERAD, NIA-Reagan, global AD pathology) were computed.

Results:

In linear regression models, the higher brain bromine levels were associated with more AD neuropathology (Braak (p trend = 0.01); CERAD (p trend = 0.02); NIA-Reagan (p trend = 0.02).

Conclusion:

Bromine accumulation in the brain is associated with higher level of AD neuropathology. The potential deleterious effects of this element on AD need further exploration.
Proteomic and Unbiased Post-Translational Modification Profiling of Amyloid Plaques and Surrounding Tissue in a Transgenic Mouse Model of Alzheimer’s Disease
Authors: Bastrup Joakim , Kastaniegaard Kenneth , Asuni Ayodeji A. , Volbracht Christiane , Stensballe Allan
Published: November 2019

Amyloid plaques are one of the hallmarks of Alzheimer’s disease (AD). The main constituent of amyloid plaques is amyloid-β peptides, but a complex interplay of other infiltrating proteins also co-localizes. We hypothesized that proteomic analysis could reveal differences between amyloid plaques and adjacent control tissue in the transgenic mouse model of AD (APPPS1-21) and in similar regions from non-transgenic littermates. Our microproteomic strategy included isolation of regions of interest by laser capture microdissection and analysis by liquid chromatography mass spectrometry-based label-free relative quantification. We consistently identified 183, 224, and 307 proteins from amyloid plaques, adjacent control and non-tg samples, respectively. Pathway analysis revealed 27 proteins that were significantly regulated when comparing amyloid plaques and corresponding adjacent control regions. We further elucidated that co-localized proteins were subjected to post-translational modifications and are the first to report 193 and 117 unique modifications associated to amyloid plaques and adjacent control extracts, respectively. The three most common modifications detected in proteins from the amyloid plaques were oxidation, deamidation, and pyroglutamylation. Together, our data provide novel information about the biological processes occurring within and around amyloid plaques in the APPPS1-21 mouse model of AD.
Towards a shared infrastructure for online job advertisement data
Authors: Descy Pascaline , Kvetan Vladimir , Wirthmann Albrecht , Reis Fernando
Published: November 2019

Following the increasing penetration of the internet, the number of websites that advertise jobs is growing. The European Centre for the Development of Vocational Training (Cedefop) and the ESSnet Big Data have engaged in parallel projects to assess the feasibility of using online job advertisements (OJA) for labour market analysis and job vacancy statistics. After an initial feasibility study finalised in 2016, Cedefop is developing a Pan-EU system providing information on skills demand present in OJA, which will be operational by 2020. The ESSnet has focussed on statistics that can be derived from OJA and entered into a second phase in November 2018 aiming at creating the conditions for a larger scale implementation of the use of OJA in official statistics. This paper builds on experiences gathered in both projects and identifies opportunities and limitations of using OJA for the above-mentioned purposes. In addition, it discusses the feasibility of creating a joint system for processing and analysing OJA data based on discussions that have taken place in the past two years between Cedefop and the ESSnet Big Data on both projects. In this respect, this paper outlines a possible partnership between Cedefop and the European Statistical System to create and manage a unique source of OJA data that would serve multiple uses in the domain of labour market analysis and official statistics. It presents potential types of (statistical) data and variables based on the information contained in OJAs at European, national and regional levels. Data limitations linked to OJAs nature and specificities will be stressed, too. The paper concludes that there is high potential for combining institutional efforts and creating a joint data collection and processing system on OJA and intends to feed a discussion on the feasibility and the implications of creating a European system for OJA, which can serve European and national needs.
The ataxic mouse as a model for studying downbeat nystagmus
Authors: Stahl John S. , Thumser Zachary C. , Oommen Brian S.
Published: December 2019

Downbeat nystagmus (DBN) is a common eye movement complication of cerebellar disease. Use of mice to study pathophysiology of vestibulocerebellar disease is increasing, but it is unclear if mice can be used to study DBN; it has not been reported in this species. We determined whether DBN occurs in the ataxic mutant tottering, which carries a mutation in the Cacna1a gene for P/Q calcium channels. Spontaneous DBN occurred only rarely, and its magnitude did not exhibit the relationship to head tilt seen in human patients. DBN during yaw rotation was more common and shares some properties with the tilt-independent, gaze-independent component of human DBN, but differs in its dependence on vision. Hyperactivity of otolith circuits responding to pitch tilts is hypothesized to contribute to the gaze-independent component of human DBN. Mutants exhibited hyperactivity of the tilt maculo-ocular reflex (tiltMOR) in pitch. The hyperactivity may serve as a surrogate for DBN in mouse studies. TiltMOR hyperactivity correlates with hyperdeviation of the eyes and upward deviation of the head during ambulation; these may be alternative surrogates. Muscimol inactivation of the cerebellar flocculus suggests a floccular role in the tiltMOR hyperactivity and provides insight into the rarity of frank DBN in ataxic mice.
The effect of vestibular rehabilitation on adults with bilateral vestibular hypofunction: A systematic review
Authors: Porciuncula Franchino , Johnson Connie C. , Glickman Leslie B.
Published: December 2019

Purpose: Adults with bilateral vestibular hypofunction (BVH) experience significant disability. A systematic review assessed evidence for vestibular rehabilitation (VR). Number of studies: 14 studies. Materials/methods: Search identification of studies based on inclusion criteria: (a) population: adults with BVH of peripheral origin; (b) interventions: vestibular exercises, balance training, education, or sensory prosthetics; (c) comparison: single interventions or compared to another psychophysical intervention, placebo, or healthy population; (d) outcomes: based on International Classification of Functioning, Disability and Health (ICF) Body Functions and Structure, Activity, and Participation; (e) study designs: prospective and interventional, Levels of Evidence I to III per Centre of Evidence-based Medicine grading. Coding and appraisal based on ICF framework and strength of evidence synthesis. Results: Five Level II studies and nine Level III studies: All had outcomes on gaze and postural stability, five with outcomes on gait speed and perceptions of oscillopsia and disequilibrium. Conclusions: (a) Moderate evidence strength on improved gaze and postural stability (ICF-Body Functions) following exercise-based VR; (b) Inadequate number of studies supporting benefit of VR on ICF-Participation outcomes; (c) Sensory prosthetics in early phase of development. Clinical relevance: Moderate evidence strength in support of VR from an impairment level; clinical practice and research needed to explore interventions extending to ICF-Activity and Participation.
Symptoms elicited in persons with vestibular dysfunction while performing gaze movements in optic flow environments1
Authors: Whitney Susan L. , Sparto Patrick J. , Cook James R. , Redfern Mark S. , Furman Joseph M.
Published: December 2019

Introduction: People with vestibular disorders often experience space and motion discomfort when exposed to moving or highly textured visual scenes. The purpose of this study was to measure the type and severity of symptoms in people with vestibular dysfunction during coordinated head and eye movements in optic flow environments. Methods: Seven subjects with vestibular disorders and 25 controls viewed four different full-field optic flow environments on six different visits. The optic flow environments consisted of textures with various contrasts and spatial frequencies. Subjects performed 8 gaze movement tasks, including eye saccades, gaze saccades, and gaze stabilization tasks. Subjects reported symptoms using Subjective Units of Discomfort (SUD) and the Simulator Sickness Questionnaire (SSQ). Self-reported dizziness handicap and space and motion discomfort were also measured. Results/conclusion: Subjects with vestibular disorders had significantly greater discomfort, oculomotor and disorientation symptoms, with some amount of symptoms in 55–60% of the trials, compared with control subjects, who had symptoms in less than 20% of the trials. The magnitude of the symptoms increased during each visit, but did not depend on the optic flow condition. Subjects who reported greater dizziness handicap and space and motion discomfort had greater severity of symptoms during the experiment (Spearman rho > 0.78). Compared with controls, subjects with vestibular disorders had about 10 deg less head excursion during the gaze saccade tasks. Overall, performance of gaze pursuit and gaze stabilization tasks in moving visual environments elicited greater symptoms in subjects with vestibular disorders compared with healthy subjects.
Symptomatic treatment of vestibular deficits: Therapeutic potential of histamine H4 receptors
Authors: Wersinger Eric , Gaboyard-Niay Sophie , Travo Cécile , Soto Enrique , Baez Adriana , Vega Rosario , Brugeaud Aurore , Chabbert Christian
Published: December 2019

Vestibular disorders display high prevalence and can severely impact the daily life. However, pharmacological options that would efficiently relieve the vertigo symptoms without side effects are still lacking. In the present review we briefly review the common history of histamine receptor modulation and the pharmacological therapy of vestibular disorders. We also discuss the recent demonstration of Histamine H4 Receptor mRNAs expression in Scarpa's ganglion of mammal and the potential use of specific H4R antagonists as vestibulomodulators. Additional original data confirm the expression of H4R proteins in the rat vestibular primary neurons, the neuromodulatory properties of specific H4R antagonists in vitro (inhibition of vestibular neuron excitability) as well as their efficacy to decrease vestibular deficits induced in different in animal models.
Betahistine treatment in managing vertigo and improving vestibular compensation: Clarification
Authors: Lacour Michel
Published: December 2019

Betahistine dihydrochloride (betahistine) is currently used in the management of vertigo and vestibular pathologies with different aetiologies. The main goal of this review is to clarify the mechanisms of action of this drug, responsible for the symptomatic relief of vertigo and the improvement of vestibular compensation. The review starts with a brief summary recalling the role of histamine as a neuromodulator/neurotransmitter in the control of the vestibular functions, and the role of the histaminergic system in vestibular compensation. Then are presented data recorded in animal models demonstrating that betahistine efficacy can be explained by mechanisms targeting the histamine receptors (HRs) at three different levels: the vascular tree, with an increase of cochlear and vestibular blood flow involving the H1R; the central nervous system, with an increase of histamine turnover implicating the H3R, and the peripheral labyrinth, with a decrease of vestibular input implying the H3R/H4R. Clinical data from vestibular loss patients show the impact of betahistine treatment for the long-term control of vertigo, improvement of balance and quality of life that can be explained by these mechanisms of action. However, two conditions, at least, are required for reaching the betahistine therapeutic effect: the dose and the duration of treatment. Experimental and clinical data supporting these requirements are exposed in the last part of this review.
Effects of distance and duration on vertical dynamic visual acuity in screening healthy adults and people with vestibular disorders
Authors: Peters Brian T. , Cohen Helen S. , Sangi-Haghpeykar Haleh , Bloomberg Jacob J.
Published: December 2019

Background: Dynamic visual acuity (DVA) testing may be a useful, indirect indicator of vestibulo-ocular reflex function. Previous evidence shows that acuity for 2 m targets differs little between patients and normals using a 75 ms display duration and that healthy subjects do not differ in acuity when standing and walking while viewing a far target but they do differ when viewing a near target. Objective: Improve the protocol of a screening tool by testing the hypothesis that healthy control subjects and patients and with unilateral peripheral vestibular weakness differ on DVA when viewing far targets while seated. Methods: Controls and patients were tested while they were seated in a chair that oscillated vertically at 2 Hz. They viewed a computer screen 4 m away, while stationary and while moving, with viewing times of either 75 ms or 500 ms. Results: The amount of change between static and dynamic conditions did not differ significantly between patients and controls for the 75 ms condition but controls had lower difference scores than patients when using the 500 ms duration. The ROC value was low, 0.68. Compared to historical data using the 75 ms duration at a distance of 2 m, subjects in both diagnostic groups had better visual acuity at the 75 ms/4 m distance. Conclusions: These results suggest that using the longer duration is better for differentiating patients from healthy controls and they support previous evidence showing that near target viewing is more challenging.
Perception of verticality and cardiovascular responses during short-radius centrifugation
Authors: Clément Gilles , Delière Quentin , Migeotte Pierre-François
Published: December 2019

Background: Artificial gravity using short-radius centrifugation has been proposed as an integrative countermeasure during spaceflight. Objective: To determine the rotation parameters of a short-radius centrifuge so that subjects rotating in the dark would feel as if they were standing upright. Methods: Twelve subjects were lying supine in a nacelle on a 2.8 m-radius centrifuge with their head closer to the axis of rotation and their feet pointing radially outwards. Subjects verbally reported body orientation for 26 combinations of centrifuge rotation rate and nacelle pitch tilt. ECG and respiratory responses were also recorded. Results: Five subjects felt like they were vertical when centrifugation elicited 1 g at their center of mass along their body longitudinal axis, whereas seven subjects felt they were vertical when they experienced about 1 g at ear level, regardless of the nacelle tilt angle. Heart rate variability varied with the subjects' perception of verticality. Conclusions: These results suggest that one group of subject was relying principally on the otolith organs for the perception of verticality, whereas the other group was also relying on extravestibular somatosensory receptors. The crewmember's perception of verticality might be a factor to take into account for the prescription for artificial gravity during spaceflight.
The influence of visual vertigo and vestibulopathy on oculomotor responses
Authors: Zur Oz , Dickstein Ruth , Dannenbaum Elizabeth , Carmeli Eli , Fung Joyce
Published: December 2019

Objective: Dynamic visual inputs can cause visual vertigo (VV) in patients with vestibulopathy, leading to dizziness and falls. This study investigated the influence of VV on oculomotor responses. Methods: In this cross-sectional, single-blind study, with experimental and control groups, 8 individuals with vestibulopathy and VV, 10 with vestibulopathy and no VV, and 10 healthy controls participated. Oculomotor responses were examined with 2-dimensional video-oculography. Participants were exposed to dynamic visual inputs of vertical stripes sweeping across a screen at 20 deg/sec, while seated or in Romberg stance, with and without a fixed target. Responses were quantified by optokinetic nystagmus frequency (OKNf) and gain (OKNg). Results: Seated with no target, VV participants had higher OKNf than controls (37 ± 9 vs. 24 ± 9 peaks/sec; P< 0.05). In Romberg stance with no target, they had higher OKNf than controls (41 ± 9 vs. 28 ± 10 peaks/sec; P< 0.05). With a target, OKNf was higher in VV participants compared to controls (7 ± 7 vs. 1 μ 2 peaks/sec; P< 0.05). In Romberg with no target, OKNg was higher in the VV group (0.8 ± 0.1) compared to controls (0.6 ± 0.2; P=0.024). OKNf and OKNg did not differ according to VV status. Conclusions: VV participants had increased OKNf and OKNg compared to healthy participants. Visual dependency should be considered in vestibular rehabilitation.
Effect of Aging on Vertical Visual Tracking and Visual-Vestibular Interaction
Authors: Demer Joseph L.
Published: December 2019

We investigated the effect of aging on vertical smooth pursuit, small-field optokinetic nystagmus (OKN), the vestibulo-ocular reflex (VOR), and visual-vestibular interactions (VVI). Telescopic spectacles were used to magnify the visual effects of head movements and accentuate the demand on VVI. Eleven normally sighted young subjects (age 30 ± 6 y, mean ± SD), and 9 normally sighted elderly subjects (age 70 ± 8 y) were studied. Three types of stimulus motion were used: 1) predictable single sinusoidal frequencies from 0.8 to 3.2 Hz, 2) poorly predictable motion consisting of a sum of multiple harmonics of a 0.4 Hz fundamental, and 3) unpredictable velocity impulses. Tracking gains declined with frequency and stimulus unpredictability but were always greater for young than elderly subjects. Pursuit gain was always less than OKN gain for subjects tested under comparable conditions of frequency and velocity. In both subject groups, pursuit and OKN tracking exhibited phase lags at higher frequencies, particularly for poor predictable motion. Tracking phase lags were greater for pursuit than OKN and were consistently greater in the elderly than in young subjects. In young subjects, stimulus dimming using a 2 log neutral density filter reduced tracking gains and increased phase lags. In both young and elderly subjects, VOR gain was <1.0 at low frequencies and increased slightly with increasing frequency. Visually enhanced VOR gain during normal vision was the ideal value of 1.0 at all frequencies in both subject groups. During wearing of telescopic spectacles, the young subjects exhibited marked gain enhancement that was greatest at lower frequencies and greater during predictable than unpredictable motion. Young subjects were able to suppress the VOR by fixation of real or imaginary targets moving with the head; this suppression was better at the lowest frequencies and for predictable motion. Phase errors were substantial for significant VVI in young subjects but were minimal in the elderly. Visual enhancement of VOR gain, as well as suppression by real and imaginary head-fixed targets, were attenuated in the elderly subjects. During rotations in which young subjects wore 4 × telescopic spectacles, 2 log unit dimming of the visual environment reduced gain and increased phase lags. The deficiencies in VVI exhibited by elderly subjects are attributable both to deficits in the visual tracking component, as well as to nonvisual mechanisms, because even changes in mental set are less effective in modifying gain in older subjects. Tracking phase lags and gain reductions in the elderly can be simulated in young subjects by substantially reducing stimulus luminance, which prolongs afferent visual latency.
Dynamic Platform Sway Measurement in Menière'S Disease
Authors: Morrison Gavin , Hawken Malcolm , Kennard Christopher , Kenyon Guy
Published: December 2019

Fourteen patients in the latent phase of Menière's disease and 14 control subjects were tested on a moving platform apparatus as part of a protocol of investigations for Menière's disease. Subjects were tested under 3 different visual conditions (eyes open, eyes closed, sway feedback) and 2 proprioceptive conditions (fixed platform and ankle stabilization). There was a significant interaction between subject group and visual condition, Menière's patients bad a larger RMS sway amplitude than controls with their eyes open and closed, but this difference was abolished by sway feedback. Loss of either visual or proprioceptive sensory information increased sway amplitude, indicating that both cues influence postural control, and in different ways, but patients were able to use these cues to maintain upright posture almost as effectively as controls. More patients than controls lost balance with ankles stabilized and eyes closed, but the difference was not statistically significant (P=0.0516). There was no detectable relationship between clinical ratings of disease severity and sway scores. The dynamic platform tests described in this report are more suitable for tests involving comparisons between groups of subjects rather than for diagnostic testing of individuals.
Reorientation of Poststimulus Nystagmus in Tilted Humans1
Authors: Furman Joseph M. , Koizuka Izumi
Published: December 2019

Recent studies indicate that the direction of postrotatory nystagmus and optokinetic afternystagmus reorients toward earth-horizontal in tilted subjects. To further examine this phenomenon in humans, we studied 8 adults (4M, 4F) with no history of neurologic or otologic disease. Vestibular stimulation consisted of yaw off-vertical axis rotation (OVAR) trapezoids with eyes open in the dark at 60°/s constant velocity with a tilt angle of 30° and a deceleration at 100°/s2 to a stop in either the right-ear-down or the left-ear-down position. The optokinetic stimulus consisted of 5° wide black and white stripes projected against a cylindrical visual surround 1 m in diameter rotated at a constant velocity of 30°/s. The projector, visual surround, and subject were all tilted by 30°; subjects were placed either in the right-ear-down or left-ear-down position. Eye position was measured using the magnetic scleral search coil technique. Each trial was scrutinized for the presence of reorientation of nystagmus in the subject's roll plane by looking for vertical nystagmus in the appropriate direction. Results indicated that reorientation of postrotatory nystagmus following OVAR was variable but often present. Reorientation of optokinetic afternystagmus was neither as consistent nor as robust as that seen following OVAR. These findings confirm that humans exhibit a predilection for eye rotations in the earth-horizontal plane. The presence of reorientation of postrotatory nystagmus (and to a lesser extent of optokinetic afternystagmus) suggests that static otolith inputs, which are known to alter velocity storage dynamics, also appear to alter the relative influence of velocity storage in different directions in humans.
Quantitative Distribution of Amino Acids in the Rat Vestibular Nuclei
Authors: Li Hongyan , Godfrey Donald A. , Rubin Allan M.
Published: December 2019

The normal concentrations of 12 amino acids in the vestibular nuclei of rats were quantitatively measured using microdissection of freeze-dried brain sections combined with high performance liquid chromatography (HPLC) analysis. Doth excitatory amino acids, aspartate and glutamate, showed only small variation across the vestibular nuclei. The distribution of glutamine tended to parallel that of glutamate. The inhibitory amino acids, gamma-aminobutyrate (GABA) and glycine, were much more concentrated in some regions than in others. GABA tended to be more concentrated than glycine in dorsal and rostral nuclei, while glycine tended to be more concentrated than GABA in ventral and caudal nuclei. The distribution of taurine was comparable to that of GABA, suggesting a close relationship with GABA function. Asparagine, serine, threonine, arginine, alanine and tyrosine had relatively low concentrations without significant differences among vestibular nuclei. Our results suggest that (1) different parts of the vestibular nuclear complex may receive similar amounts of excitatory amino acid afferents, (2) there is predominance of GABA or glycine as an inhibitory transmitter in different parts of the vestibular nuclear complex, and (3) there may be a close functional relationship between taurine and GABA within the vestibular nuclear complex. These results provide data basic to further research on the details of amino acid functions in the normal and abnormal vestibular system, as well as studies of plasticity in this system.
Benign Paroxysmal Positional Vertigo of the Horizontal Canal: A Form of Canalolithiasis with Variable Clinical Features
Authors: Nuti Daniele , Vannucchi Paolo , Pagnini Paolo
Published: December 2019

Benign paroxysmal positional vertigo of the horizontal semicircular canal (HC-BPPV) is a well-defined syndrome characterized by direction-changing horizontal positional nystagmus. We report the clinical features of 5 patients who illustrate the possible variables of the syndrome. In most cases, nystagmus is geotropic and more intense when the pathological ear is lowermost; less often the syndrome presents with apogeotropic nystagmus that is more intense when the affected ear is uppermost. The nystagmus pattern may vary in time in the same patient, changing from apogeotropic to geotropic even in observations at short intervals. In some patients, the features indicate involvement of more than one canal, either simultaneously or in succession. It is sustained that the clinical findings can be explained by movement of endolymph caused by displacement of otoconia in the semicircular canals and that variants are due to different positions of the otoconia within the canals.
Psychophysical Scaling of Circular Vection (CV) Produced by Optokinetic (OKN) Motion: Individual Differences and Effects of Practice
Authors: Kennedy Robert S. , Hettinger Lawrence J. , Harm Deborah L. , Ordy J. Mark , Dunlap William P.
Published: December 2019

Vection (V) refers to the compelling visual illusion of self-motion experienced by stationary individuals when viewing moving visual surrounds. The phenomenon is of theoretical interest because of its relevance for understanding the neural basis of ordinary self-motion perception, and of practical importance because it is the experience that makes simulation, virtual reality displays, and entertainment devices more vicarious. This experiment was performed to address whether an optokinetically induced vection illusion exhibits monotonic and stable psychometric properties and whether individuals differ reliably in these (V) perceptions. Subjects were exposed to varying velocities of the circular vection (CV) display in an optokinetic (OKN) drum 2 meters in diameter in 5 one-hour daily sessions extending over a 1 week period. For grouped data, psychophysical scalings of velocity estimates showed that exponents in a Stevens' type power function were essentially linear (slope =0.95) and largely stable over sessions. Latencies were slightly longer for the slowest and fastest induction stimuli, and the trend over sessions for average latency was longer as a function of practice implying time course adaptation effects. Test-retest reliabilities for individual slope and intercept measures were moderately strong (r=0.45) and showed no evidence of superdiagonal form. This implies stability of the individual circularvection (CV) sensitivities. Because the individual CV scores were stable, reliabilities were improved by averaging 4 sessions in order to provide a stronger retest reliability (r=0.80). Individual latency responses were highly reliable (r=0.80). Mean CV latency and motion sickness symptoms were greater in males than in females. These individual differences in CV could be predictive of other outcomes, such as susceptibility to disorientation or motion sickness, and for CNS localization of visual-vestibular interactions in the experience of self-motion.
Connections Between the Vestibular Nuclei and Brain Stem Regions That Mediate Autonomic Function in the Rat
Authors: Porter Jennifer D. , Balaban Carey D.
Published: December 2019

Clinical observations have long indicated a vestibular influence on autonomic function. Neuroanatomical studies in the rabbit and in the cat have identified descending vestibulo-autonomic pathways from the caudal portion of the medial vestibular nucleus and the inferior vestibular nucleus to the dorsal motor nucleus of the vagus nerve, the nucleus of the solitary tract, and some brain stem medullary sympathetic regions. This study describes vestibulo-autonomic pathways in rats. One group of Long-Evans rats received injections of tetramethylrhodamine dextran into the caudal aspect of the vestibular nuclear complex. Anterogradely labeled descending fibers were traced bilaterally to lateral, ventrolateral, and intermediate subnuclei of the nucleus of the solitary tract and the dorsal motor nucleus of the vagus nerve. A small number of axons also projected bilaterally to the nucleus ambiguus, the ventrolateral medulla, and the nucleus raphe magnus. Finally, anterogradely labeled ascending fibers were traced from the caudal medial vestibular nucleus and the inferior vestibular nucleus to the medial, lateral, ventrolateral, and Kolliker-Fuse regions of parabrachial nucleus. A second group of rats received iontophoretic injections of Flu oro-gold into the nucleus of the solitary tract to identify the cells of origin of the vestibulo-solitary projection. Similar to findings in the rabbit (Balaban and Beryozkin, 1994), retrogradely labeled cells were observed in the caudal medial vestibular nucleus and the inferior vestibular nucleus. These findings are consistent with the hypothesis that a common pattern of vestibular nuclear projections to autonomic regions is shared by rabbits, cats, and rats.
Eye-Head Coordination toward Auditory and Visual Targets in Humans
Authors: Zambarbieri Daniela , Schmid Roberto , Versino Maurizio , Beltrami Giorgio
Published: December 2019

Eye–head coordination during gaze orientation toward auditory targets in total darkness has been examined in human subjects. The findings have been compared, for the same subjects, with those obtained by using visual targets. The use of auditory targets when investigating eye–head coordination has some advantages with respect to the more common use of visual targets: (i) more eccentric target positions can be presented to the subject; (ii) visual feedback is excluded during the execution of gaze displacement; (iii) complex patterns of saccadic responses can be elicited. This last aspect is particularly interesting for examining the coupling between the eyes and the head displacements. The experimental findings indicate that during gaze orientation toward a visual or an auditory target the central nervous system adopts the same strategy of using both the saccadic mechanism and the head motor plant. In spite of a common strategy, qualitative and quantitative parameters of the resulting eye–head coordination are slightly different, depending on the nature of the target. The findings relating to patterns of eye–head coordination seem to indicate a dissociation between the eyes and the head, which receive different motor commands independently generated from the gaze error signal. The experimental findings reported in this paper have been summarized in a model of the gaze control system that makes use of a gaze feedback hypothesis through the central reconstruction of the eye and head positions.
Sleep and Vestibular Adaptation: Implications for Function in Microgravity
Authors: Hobson J. Allan , Stickgold Robert , Pace-Schott Edward F. , Leslie Kenneth R.
Published: December 2019

Optimal human performance depends upon integrated sensorimotor and cognitive functions, both of which are known to be exquisitely sensitive to loss of sleep. Under the microgravity conditions of space flight, adaptation of both sensorimotor (especially vestibular) and cognitive functions (especially orientation) must occur quickly-and be maintained-despite any concurrent disruptions of sleep that may be caused by microgravity itself, or by the uncomfortable sleeping conditions of the spacecraft. It is the three-way interaction between sleep quality, general work efficiency, and sensorimotor integration that is the subject of this paper and the focus of new work in our laboratory. To record sleep under field conditions including microgravity, we utilize a novel system called the Nightcap that we have developed and extensively tested on normal and sleep-disordered subjects. To perturb the vestibular system in ground-based studies, we utilize a variety of experimental conditions including optokinetic stimulation and both minifying and reversing goggle paradigms that have been extensively studied in relation to plasticity of the vestibulo-ocular reflex. Using these techniques we will test the hypothesis that vestibular adaptation both provokes and is enhanced by REM sleep under both ground-based and space conditions. In this paper we describe preliminary results of some of our studies.
The Adequate Stimulus for Avian Short Latency Vestibular Responses to Linear Translation
Authors: Jones Timothy A. , Jones Sherri M. , Colbert Stephen
Published: December 2019

Transient linear acceleration stimuli have been shown to elicit eighth nerve vestibular compound action potentials in birds and mammals. The present study was undertaken to better define the nature of the adequate stimulus for neurons generating the response in the chicken (Gallus domesticus). In particular, the study evaluated the question of whether the neurons studied are most sensitive to the maximum level of linear acceleration achieved or to the rate of change in acceleration (da/dt, or jerk). To do this, vestibular response thresholds were measured as a function of stimulus onset slope. Traditional computer signal averaging was used to record responses to pulsed linear acceleration stimuli. Stimulus onset slope was systematically varied. Acceleration thresholds decreased with increasing stimulus onset slope (decreasing stimulus rise time). When stimuli were expressed in units of jerk (g/ms), thresholds were virtually constant for all stimulus rise times. Moreover, stimuli having identical jerk magnitudes but widely varying peak acceleration levels produced virtually identical responses. Vestibular response thresholds, latencies and amplitudes appear to be determined strictly by stimulus jerk magnitudes. Stimulus attributes such as peak acceleration or rise time alone do not provide sufficient information to predict response parameter quantities. Indeed, the major response parameters were shown to be virtually independent of peak acceleration levels or rise time when these stimulus features were isolated and considered separately. It is concluded that the neurons generating short latency vestibular evoked potentials do so as “jerk encoders” in the chicken. Primary afferents classified as “irregular”, and which traditionally fall into the broad category of “dynamic” or “phasic” neurons, would seem to be the most likely candidates for the neural generators of short latency vestibular compound action potentials.
The EMG Development of the Longissimus and Multifidus Muscles After Plugging the Horizontal Semicircular Canals
Authors: Geisler Hildegard C. , Gramsbergen Albert
Published: December 2019

The effects of plugging both horizontal semicircular canals at the 5th postnatal day (P5) on the development of the EMG of two back muscles (the M. longissimus lateralis and the M. multifidus) were studied in rats between P5 and P46. The EMG was related to locomotion, grooming, and rearing of these rats. Special attention was paid to locomotor behavior. After this vestibular deprivation, the development of a consistent temporal relation between burst activity in the EMG of both Mm. longissimii laterales and the swing phase of one hind paw was retarded by about 3 days. The development of coupling of maximal activity in the M. longissimus lateralis to the swing phase of one of the hind paws was even more retarded. No differences were observed between normal and vestibularly deprived rats during the development of activity in the Mm. multifidi. Our results indicate that information from the horizontal semicircular canals is essential for dynamic postural development and probably, therefore, for motor development in general. Furthermore, lack of such information has effects on the fine tuning of back muscle activity during locomotion at least until P40.
Principles Underlying Real-Time Nystagmus Analysis of Horizontal and Vertical Eye Movements Recorded With Electro-, Infra-Red-, or Video-Oculographic Techniques
Authors: Allum J.H.J. , Honegger F. , Troescher M.
Published: December 2019

New methods for separating fast and slow phases of human nystagmus in real time are presented that are adaptive to the time-dependent noise properties of the input eye movement signal and therefore applicable to different recording techniques and directions. The methods employ a statistical filter technique to track slow-phase eye movements, uninfluenced by fast phases and blink artifacts, and fuzzy-logic techniques to identify fast-phase eye movements. Because these two techniques are decoupled from one another, highly accurate phase separation and slow-phase velocity profiles are achieved. In addition, the tracking of the variance of slow-phase and fast-phase eye movement recording permits a quality control of the analysis for different recording techniques and a variety of ocular nystagmus responses. Because blinks impose different eye velocity profiles on the recordings, depending on the type of recording technique and direction (horizontal, vertical), blink detection and its effect on fast-phase amplitude must be individually adjusted to each recording technique. Results are illustrated in the context of simultaneously recorded video-oculographic, infra-red, and electro-oculographic recordings of vestibulo-ocular reflex and optokinetic reflex responses causing horizontal or vertical eye movements.
Behavior of toads, Bufo bufo, in a dynamic environment
Authors: Lychakov D.V.
Published: December 2019

Susceptibility to motion sickness was tested by exposing free moving toads to rotation of a stimulator modeled after an amusement park Ferris Wheel. The stimulator provided a gentle stimulation of frequency 0.25 Hz and centrifugal acceleration 0.143 g during 120 min or more without external visual cues. No emetic or prodromal behavioral response was elicited during or after rotation. During rotation the amount of motor activity in most toads increased evidently. The most active toads attempted to climb out of the test chamber. It was inferred that experimental rotation was rather a stressful stimulus which initiated an escape response. In addition, during rotation the number of eye retractions and urination incidences increased, but appetite after rotation was inhibited. During rotation the motionless toads performed small regular head movements with period equal to rotation period of stimulator. These oscillations were probably vestibular (otolith) reaction to oscillating acceleration. The proposed resonance hypothesis gives a general idea of why lower vertebrates are immune to motion sickness.
Proteomic analysis of the rat cerebellar flocculus during vestibular compensation
Authors: Fukasawa Masahiko , Okamoto Kazuki , Nakamura Manabu , Mikami Koshi , Shimada Sonoko , Tanaka Yasuhiko , Nagai Kouhei , Arito Mitsumi , Kurokawa Manae S. , Masuko Kayo , Suematsu Naoya , Koizuka Izumi , Kato Tomohiro
Published: December 2019

Unilateral labyrinthectomy (UL) in rats is used as a human vertigo model. In this model, spontaneous nystagmus and dysequilibrium caused by UL are ameliorated within 48–72 hours. The amelioration, termed vestibular compensation (VC), is long lasting. Although cerebellar flocculi have been reported to be involved in VC, the molecular mechanisms behind VC are unknown. In this study, we used 2D-DIGE to detect protein changes in flocculi during acute (48 hours) and chronic (1 week) stages of VC. We found 99 out of 967 protein spots that showed significant changes in their intensities. Of the 99 spots, 45 spots (ipsilateral side, 15; contralateral side, 30) changed unilaterally during the acute stage, whereas 46 spots (ipsilateral side, 21; contralateral side, 25) changed unilaterally during the chronic stage. Thus, the acute compensation mechanism is more complicated in the contralateral flocculus than in the ipsilateral flocculus. Using MALDI-TOF MS, we identified 10 proteins out of the 12 protein spots. Of these, 3 proteins involved in synaptic transmission, neuronal filament formation and vesicular transport, respectively, demonstrated altered expression only in the acute stage. Our results enhance the understanding of the role of the cerebellar flocculi in VC generation.
Differentiating ascending vestibular pathways to the cortex involved in spatial cognition
Authors: Shinder Michael E. , Taube Jeffrey S.
Published: December 2019

Vestibular information is an important factor in maintaining accurate spatial awareness. Yet, each of the cortical areas involved in processing vestibular information has unique functionality. Further, the anatomical pathways that provide vestibular input for cognitive processes are also distinct. This review outlines some of the current understanding of vestibular pathways contributing to the perception of self-motion in the cortex. The vestibulo-thalamic pathway is associated with self-motion cues for updating motor behaviors, spatial representations, and self versus object motion distinctions. The mammillo-tegmental pathway supplies vestibular input to create a cognitive representation of head direction. Self-motion and head direction information then converge to define self-location. By outlining the functional anatomy of the vestibular cortical pathways, a multi-sensory and multi-faceted view of vestibular related spatial awareness emerges.