Sensorimotor aspects of high-speed artificial gravity: I. Sensory conflict in vestibular adaptation

2003 ◽  
Vol 12 (5-6) ◽  
pp. 271-282 ◽  
Author(s):  
Erika L. Brown ◽  
Heiko Hecht ◽  
Laurence R. Young
Keyword(s):  
High Speed ◽  
Motor Coordination ◽  
Head Movements ◽  
Body Tilt ◽  
Sensory Conflict ◽  
Rotation Rates ◽  
Coriolis Effects ◽  
Gain Adaptation ◽  
Intersensory Conflict ◽  
Vertical Nystagmus

Short-radius centrifugation offers a promising and affordable countermeasure to the adverse effects of prolonged weightlessness. However, head movements made in a fast rotating environment elicit Coriolis effects, which seriously compromise sensory and motor processes. We found that participants can adapt to these Coriolis effects when exposed intermittently to high rotation rates and, at the same time, can maintain their perceptual-motor coordination in stationary environments. In this paper, we explore the role of inter-sensory conflict in this adaptation process. Different measures (vertical nystagmus, illusory body tilt, motion sickness) react differently to visual-vestibular conflict and adapt differently. In particular, proprioceptive-vestibular conflict sufficed to adapt subjective parameters and the time constant of nystagmus decay, while retinal slip was required for VOR gain adaptation. A simple correlation between the strength of intersensory conflict and the efficacy of adaptation fails to explain the data. Implications of these findings, which differ from existing data for low rotation rates, are discussed.

Sensorimotor aspects of high-speed artificial gravity: III. Sensorimotor adaptation

2003 ◽  
Vol 12 (5-6) ◽  
pp. 291-299
Author(s):  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Side Effects ◽  
Coriolis Force ◽  
High Speed ◽  
Motor Adaptation ◽  
Vestibular Stimulation ◽  
Head Movements ◽  
Artificial Gravity ◽  
Slow Rotation ◽  
Movement Trajectory ◽  
Rotation Rates

As a countermeasure to the debilitating physiological effects of weightlessness, astronauts could live continuously in an artificial gravity environment created by slow rotation of an entire spacecraft or be exposed to brief daily "doses" in a short radius centrifuge housed within a non-rotating spacecraft. A potential drawback to both approaches is that head movements made during rotation may be disorienting and nauseogenic. These side effects are more severe at higher rotation rates, especially upon first exposure. Head movements during rotation generate aberrant vestibular stimulation and Coriolis force perturbations of the head-neck motor system. This article reviews our progress toward distinguishing vestibular and motor factors in side effects of rotation, and presents new data concerning the rates of rotation up to which adaptation is possible. We have studied subjects pointing to targets during constant velocity rotation, because these movements generate Coriolis motor perturbations of the arm but do not involve unusual vestibular stimulation. Initially, reaching paths and endpoints are deviated in the direction of the transient lateral Coriolis forces generated. With practice, subjects soon move in straighter paths and land on target once more. If sight of the arm is permitted, adaptation is more rapid than in darkness. Initial arm movement trajectory and endpoint deviations are proportional to Coriolis force magnitude over a range of rotation speeds from 5 to 20 rpm, and there is rapid, complete motor adaptation at all speeds. These new results indicate that motor adaptation to high rotation rates is possible. Coriolis force perturbations of head movements also occur in a rotating environment but adaptation gradually develops over the course of many head movements.

Threshold-based vestibular adaptation to cross-coupled canal stimulation

2008 ◽  
Vol 17 (4) ◽  
pp. 171-181
Author(s):  
Carol C. Cheung ◽  
Heiko Hecht ◽  
Thomas Jarchow ◽  
Laurence R. Young
Keyword(s):  
Eye Movements ◽  
Side Effects ◽  
Angular Velocity ◽  
Motion Sickness ◽  
Head Movements ◽  
Body Tilt ◽  
Rotation Rates ◽  
Vestibular Adaptation ◽  
Carry Over

Prior experiments have demonstrated that people are able to adapt to cross-coupled accelerations associated with head movements while spinning at high rotation rates (e.g., 23 rpm or 138°/s). However, while adapting, subjects commonly experience serious side effects, such as motion sickness, non-compensatory eye movements, and strong and potentially disorienting illusory body tilt or tumbling sensations. In the present study, we investigated the feasibility of adaptation using a threshold-based method, which ensured that the illusory tilt sensations remained imperceptible or just barely noticeable. This was achieved by incrementally increasing the angular velocity of the horizontal centrifuge while supine subjects made repeated consistent yaw head turns. Incremental adaptation phases started at centrifugation speeds of 3 rpm. Centrifuge speed was slowly increased in steps of 1.5 rpm until a light illusory tilt was experienced. At the end of the incremental procedure, subjects were able to make head turns while rotating 14 rpm without experiencing illusory tilt. Moreover, motion sickness symptoms could be avoided and a limited carry over of the adaptive state to stronger stimulation at 23 rpm was found. The results are compared to prior studies which adapted subjects to super-threshold stimuli.

Kinematics of Tongue Projection in Chamaeleo Oustaleti

1991 ◽  
Vol 159 (1) ◽  
pp. 109-133 ◽  
Author(s):  
PETER C. WAINWRIGHT ◽  
DAVID M. KRAKLAU ◽  
ALBERT F. BENNETT
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Maximum Velocity ◽  
Head Movements ◽  
Florida State University ◽  
State University ◽  
Maximum Acceleration ◽  
Related Family ◽  
High Speed Cinematography ◽  
Tongue Movements

The kinematics of prey capture by the chamaeleonid lizard Chamaeleo oustaleti were studied using high-speed cinematography. Three feeding sequences from each of two individuals were analyzed for strike distances of 20 and 35 cm, at 30°C. Ten distances and angles were measured from sequential frames beginning approximately 0.5 s prior to tongue projection and continuing for about 1.0 s. Sixteen additional variables, documenting maximum excursions and the timing of events, were calculated from the kinematic profiles. Quantified descriptions of head, hyoid and tongue movements are presented. Previously unrecognized rapid protraction of the hyobranchial skeleton simultaneously with the onset of tongue projection was documented and it is proposed that this assists the accelerator muscle in powering tongue projection. Acceleration of the tongue occurred in about 20ms, reaching a maximum acceleration of 486 m s−2 and maximum velocity of 5.8m s−1 in 35 cm strikes. Deceleration of the tongue usually began within 5 ms before prey contract and the direction of tongue movement was reversed within 10 ms of prey contact. Retraction of the tongue, caused by shortening of the retractor muscles, reached a maximum velocity of 2.99 ms−1 and was complete 330 ms after prey contact. Projection distance influences many aspects of prey capture kinematics, particularly projection time, tongue retraction time and the extent of gape and head movements during tongue retraction, all of which are smaller in shorter feedings. Though several features of the chameleon strike have apparently been retained from lizards not capable of ballistic tongue projection, key differences are documented. Unlike members of a related family, the Agamidae, C. oustaleti uses no body lunge during prey capture, exhibits gape reduction during tongue projection and strongly depresses the head and jaws during tongue retraction. Note: Present address: Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.

scholarly journals Psychomotor impairments and therapeutic implications revealed by a mutation associated with infantile Parkinsonism-Dystonia

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Jenny I Aguilar ◽  
Mary Hongying Cheng ◽  
Josep Font ◽  
Alexandra C Schwartz ◽  
Kaitlyn Ledwitch ◽  
...  
Keyword(s):  
High Speed ◽  
Molecular Mechanisms ◽  
Motor Coordination ◽  
Neurodegenerative Disorder ◽  
Expression System ◽  
Distinct Type ◽  
Underlying Disease ◽  
Deficiency Syndrome ◽  
Motor Deficits ◽  
Therapeutic Implications

Parkinson disease (PD) is a progressive, neurodegenerative disorder affecting over 6.1 million people worldwide. Although the cause of PD remains unclear, studies of highly penetrant mutations identified in early-onset familial parkinsonism have contributed to our understanding of the molecular mechanisms underlying disease pathology. Dopamine (DA) transporter (DAT) deficiency syndrome (DTDS) is a distinct type of infantile parkinsonism-dystonia that shares key clinical features with PD, including motor deficits (progressive bradykinesia, tremor, hypomimia) and altered DA neurotransmission. Here, we define structural, functional, and behavioral consequences of a Cys substitution at R445 in human DAT (hDAT R445C), identified in a patient with DTDS. We found that this R445 substitution disrupts a phylogenetically conserved intracellular (IC) network of interactions that compromise the hDAT IC gate. This is demonstrated by both Rosetta molecular modeling and fine-grained simulations using hDAT R445C, as well as EPR analysis and X-ray crystallography of the bacterial homolog leucine transporter. Notably, the disruption of this IC network of interactions supported a channel-like intermediate of hDAT and compromised hDAT function. We demonstrate that Drosophila melanogaster expressing hDAT R445C show impaired hDAT activity, which is associated with DA dysfunction in isolated brains and with abnormal behaviors monitored at high-speed time resolution. We show that hDAT R445C Drosophila exhibit motor deficits, lack of motor coordination (i.e. flight coordination) and phenotypic heterogeneity in these behaviors that is typically associated with DTDS and PD. These behaviors are linked with altered dopaminergic signaling stemming from loss of DA neurons and decreased DA availability. We rescued flight coordination with chloroquine, a lysosomal inhibitor that enhanced DAT expression in a heterologous expression system. Together, these studies shed some light on how a DTDS-linked DAT mutation underlies DA dysfunction and, possibly, clinical phenotypes shared by DTDS and PD.

scholarly journals Central nervous system integration of sensorimotor signals in oral and pharyngeal structures: oropharyngeal kinematics response to recurrent laryngeal nerve lesion

2016 ◽  
Vol 120 (5) ◽  
pp. 495-502 ◽  
Author(s):  
Francois D. H. Gould ◽  
Jocelyn Ohlemacher ◽  
Andrew R. Lammers ◽  
Andrew Gross ◽  
Ashley Ballester ◽  
...  
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
High Speed ◽  
Motor Coordination ◽  
Cranial Nerves ◽  
Laryngeal Nerve ◽  
Nerve Lesion ◽  
Airway Protection ◽  
Liquid Feeding ◽  
Laryngeal Sensation ◽  
Central Coordination

Safe, efficient liquid feeding in infant mammals requires the central coordination of oropharyngeal structures innervated by multiple cranial and spinal nerves. The importance of laryngeal sensation and central sensorimotor integration in this system is poorly understood. Recurrent laryngeal nerve lesion (RLN) results in increased aspiration, though the mechanism for this is unclear. This study aimed to determine the effect of unilateral RLN lesion on the motor coordination of infant liquid feeding. We hypothesized that 1) RLN lesion results in modified swallow kinematics, 2) postlesion oropharyngeal kinematics of unsafe swallows differ from those of safe swallows, and 3) nonswallowing phases of the feeding cycle show changed kinematics postlesion. We implanted radio opaque markers in infant pigs and filmed them pre- and postlesion with high-speed videofluoroscopy. Markers locations were digitized, and swallows were assessed for airway protection. RLN lesion resulted in modified kinematics of the tongue relative to the epiglottis in safe swallows. In lesioned animals, safe swallow kinematics differed from unsafe swallows. Unsafe swallow postlesion kinematics resembled prelesion safe swallows. The movement of the tongue was reduced in oral transport postlesion. Between different regions of the tongue, response to lesion was similar, and relative timing within the tongue was unchanged. RLN lesion has a pervasive effect on infant feeding kinematics, related to the efficiency of airway protection. The timing of tongue and hyolaryngeal kinematics in swallows is a crucial locus for swallow disruption. Laryngeal sensation is essential for the central coordination in feeding of oropharyngeal structures receiving motor inputs from different cranial nerves.

scholarly journals Automated video tracking and flight analysis show how bumblebees solve a pattern discrimination task using active vision

2021 ◽  
Author(s):  
HaDi MaBouDi ◽  
Mark Roper ◽  
Marie Guiraud ◽  
James A.R. Marshall ◽  
Lars Chittka
Keyword(s):  
High Speed ◽  
Discrimination Task ◽  
Active Vision ◽  
Pattern Discrimination ◽  
Relevant Information ◽  
Small Region ◽  
Video Tracking ◽  
Head Movements ◽  
Flight Behaviour ◽  
Automated Video Tracking

AbstractActive vision, the ability of the visual system to actively sample and select relevant information out of a visual scene through eye and head movements, has been explored in a variety of animal species. Small-brained animals such as insects might rely even more on sequential acquisition of pattern features since there might be less parallel processing capacity in their brains than in vertebrates. To investigate how active vision strategies enable bees to solve visual tasks, here, we employed a simple visual discrimination task in which individual bees were presented with a multiplication symbol and a 45° rotated version of the same pattern (“plus sign”). High-speed videography of unrewarded tests and analysis of the bees’ flight paths shows that only a small region of the pattern is inspected before successfully accepting a target or rejecting a distractor. The bees’ scanning behaviour of the stimuli differed for plus signs and multiplication signs, but for each of these, the flight behaviour was consistent irrespective of whether the pattern was rewarding or unrewarding. Bees typically oriented themselves at ~±30° to the patterns such that only one eye had an unobscured view of stimuli. There was a significant preference for initially scanning the left side of the stimuli. Our results suggest that the bees’ movement may be an integral part of a strategy to efficiently analyse and encode their environment.Summary statementAutomated video tracking and flight analysis is proposed as the next milestone in understanding mechanisms underpinning active vision and cognitive visual abilities of bees.

scholarly journals On Torque and Tumbling in Swimming Escherichia coli

2006 ◽  
Vol 189 (5) ◽  
pp. 1756-1764 ◽  
Author(s):  
Nicholas C. Darnton ◽  
Linda Turner ◽  
Svetlana Rojevsky ◽  
Howard C. Berg
Keyword(s):  
Escherichia Coli ◽  
High Speed ◽  
Polymorphic Transformations ◽  
Charge Coupled Device ◽  
Motor Torque ◽  
Rotation Rates ◽  
Applied Torque ◽  
Resistive Force Theory ◽  
Rotary Motor ◽  
Single Flagellum

ABSTRACT Bacteria swim by rotating long thin helical filaments, each driven at its base by a reversible rotary motor. When the motors of peritrichous cells turn counterclockwise (CCW), their filaments form bundles that drive the cells forward. We imaged fluorescently labeled cells of Escherichia coli with a high-speed charge-coupled-device camera (500 frames/s) and measured swimming speeds, rotation rates of cell bodies, and rotation rates of flagellar bundles. Using cells stuck to glass, we studied individual filaments, stopping their rotation by exposing the cells to high-intensity light. From these measurements we calculated approximate values for bundle torque and thrust and body torque and drag, and we estimated the filament stiffness. For both immobilized and swimming cells, the motor torque, as estimated using resistive force theory, was significantly lower than the motor torque reported previously. Also, a bundle of several flagella produced little more torque than a single flagellum produced. Motors driving individual filaments frequently changed directions of rotation. Usually, but not always, this led to a change in the handedness of the filament, which went through a sequence of polymorphic transformations, from normal to semicoiled to curly 1 and then, when the motor again spun CCW, back to normal. Motor reversals were necessary, although not always sufficient, to cause changes in filament chirality. Polymorphic transformations among helices having the same handedness occurred without changes in the sign of the applied torque.

Tracking Whisker and Head Movements in Unrestrained Behaving Rodents

2005 ◽  
Vol 93 (4) ◽  
pp. 2294-2301 ◽  
Author(s):  
Per Magne Knutsen ◽  
Dori Derdikman ◽  
Ehud Ahissar
Keyword(s):  
Real Time ◽  
Efficient Method ◽  
Exploratory Behavior ◽  
High Speed ◽  
Head Movements ◽  
Behavioral Data ◽  
High Speed Video ◽  
Electrophysiological Recordings ◽  
Freely Moving ◽  
Mystacial Vibrissae

Due to recent advances that enable real-time electrophysiological recordings in brains of awake behaving rodents, effective methods for analyzing the large amount of behavioral data thus generated, at millisecond resolution, are required. We describe a semiautomated, efficient method for accurate tracking of head and mystacial vibrissae (whisker) movements in freely moving rodents using high-speed video. By tracking the entire length of individual whiskers, we show how both location and shape of whiskers are relevant when describing the kinematics of whisker movements and whisker interactions with objects during a whisker-dependent task and exploratory behavior.

scholarly journals Durophagy in sharks: feeding mechanics of the hammerhead Sphyrna tiburo

2000 ◽  
Vol 203 (18) ◽  
pp. 2781-2796 ◽  
Author(s):  
C.D. Wilga ◽  
P.J. Motta
Keyword(s):  
Motor Activity ◽  
High Speed ◽  
Motor Pattern ◽  
Adductor Muscle ◽  
Head Movements ◽  
Motor Patterns ◽  
Apparent Lack ◽  
Sphyrna Tiburo ◽  
Adductor Muscles ◽  
Feeding Mechanics

This study investigates the motor pattern and head movements during feeding of a durophagus shark, the bonnethead Sphyrna tiburo, using electromyography and simultaneous high-speed video. Sphyrna tiburo feeds almost exclusively on hard-shelled crabs, with shrimp and fish taken occasionally. It captures crabs by ram feeding, then processes or reduces the prey by crushing it between molariform teeth, finally transporting the prey by suction for swallowing. The prey-crushing mechanism is distinct from that of ram or bite capture and suction transport. This crushing mechanism is accomplished by altering the duration of jaw adductor muscle activity and modifying jaw kinematics by the addition of a second jaw-closing phase. In crushing events, motor activity of the jaw adductor muscles continues (biting of the prey occurs as the jaws close and continues after the jaws have closed) throughout a second jaw-closing phase, unlike capture and transport events during which motor activity (biting) ceases at jaw closure. Sphyrna tiburo is able to take advantage of a resource (hard prey) that is not readily available to most sharks by utilizing a suite of durophagous characteristics: molariform teeth, a modified jaw protrusor muscle, altered jaw adductor activity and modified jaw kinematics. Sphyrna tiburo is a specialist feeder on crab prey as demonstrated by the lack of differences in kinematic or motor patterns when offered prey of differing hardness and its apparent lack of ability to modulate its behavior when feeding on other prey. Functional patterns are altered and coupled with modifications in dental and jaw morphology to produce diverse crushing behaviors in elasmobranchs.

Orientation illusions and heart-rate changes during short-radius centrifugation

2001 ◽  
Vol 11 (2) ◽  
pp. 115-127
Author(s):  
Heiko Hecht ◽  
Jessica Kavelaars ◽  
Carol C. Cheung ◽  
Laurence R. Young
Keyword(s):  
Heart Rate ◽  
Angular Acceleration ◽  
Constant Angular Velocity ◽  
Head Movements ◽  
Body Tilt ◽  
Main Body ◽  
Earth Gravity ◽  
Sensory Effects ◽  
Transient Elevation

Intermittent short-radius centrifugation is a promising countermeasure against the adverse effects of prolonged weightlessness. To assess the feasibility of this countermeasure, we need to understand the disturbing sensory effects that accompany some movements carried out during rotation. We tested 20 subjects who executed yaw and pitch head movements while rotating at constant angular velocity. They were supine with their main body axis perpendicular to earth gravity. The head was placed at the centrifuge's axis of rotation. Head movements produced a transient elevation of heart-rate. All observers reported head-contingent sensations of body tilt although their bodies remained supine. Mostly, the subjective sensations conform to a model based on semicircular canal responses to angular acceleration. However, some surprising deviations from the model were found. Also, large inter-individual differences in direction, magnitude, and quality of the illusory body tilt were observed. The results have implications for subject screening and prediction of subjective tolerance for centrifugation.

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