The Impact of Oral Promethazine on Human Whole-Body Motion Perceptual Thresholds

Diaz‐Artiles, Ana; Priesol, Adrian J.; Clark, Torin K.; Sherwood, David P.; Oman, Charles M.; Young, Laurence R.; Karmali, Faisal

doi:10.1007/s10162-017-0622-z

Cited by 31 publications

(9 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of stimulus-dependent imprecision could be clinically important because it implies that motion velocity is an additional dimension that can be characterized in addition to frequency (Grabherr et al, 2008) and other variables. Perceptual recognition thresholds collected using threshold-level stimuli are sensitive to disease (Lewis et al, 2011, Valko et al, 2012), medication (Diaz-Artiles et al, 2017), age (Bermudez Rey et al, 2016) and balance performance (Karmali et al, 2017), and JNDs were substantially elevated for a subject with bilateral hypofunction (Mallery et al, 2010), but further investigation will determine how other characteristics vary for suprathreshold stimuli corresponding to motion during daily activities.…”

Section: Discussionmentioning

confidence: 99%

Variability in the Vestibulo-Ocular Reflex and Vestibular Perception

Nouri

Karmali

2018

Neuroscience

Self Cite

View full text Add to dashboard Cite

The vestibular system enables humans to estimate self-motion, stabilize gaze and maintain posture, but these behaviors are impacted by neural noise at all levels of processing (e.g., sensory, central, motor). Despite its essential importance, the behavioral impact of noise in human vestibular pathways is not completely understood. Here, we characterize the vestibular imprecision that results from neural noise by measuring trial-to-trial vestibulo-ocular reflex (VOR) variability and perceptual just-noticeable differences (JNDs) in the same human subjects as a function of stimulus intensity. We used head-centered yaw rotations about an Earth-vertical axis over a broad range of motion velocities (0-65°/s for VOR variability and 3-90°/s peak velocity for JNDs). We found that VOR variability increased from approximately 0.6°/s at a chair velocity of 1°/s to approximately 3°/s at 65°/s; it exhibited a stimulus-independent range below roughly 1°/s. Perceptual imprecision ("sigma") increased from 0.76°/s at 3°/s to 4.7°/s at 90°/s. Using stimuli that manipulated the relationship between velocity, displacement and acceleration, we found that velocity was the salient cue for VOR variability for our motion stimuli. VOR and perceptual imprecision both increased with stimulus intensity and were broadly similar over a range of stimulus velocities, consistent with a common noise source that affects motor and perceptual pathways. This contrasts with differing perceptual and motor stimulus-dependent imprecision in visual studies. Either stimulus-dependent noise or non-linear signal processing could explain our results, but we argue that afferent non-linearities alone are unlikely to be the source of the observed behavioral stimulus-dependent imprecision.

show abstract

Section: Discussionmentioning

confidence: 99%

Variability in the Vestibulo-Ocular Reflex and Vestibular Perception

Nouri

Karmali

2018

Neuroscience

Self Cite

View full text Add to dashboard Cite

show abstract

“…3, and Table 5, from which we conclude that the observed differences of response variability are more likely related to body stability than to participants' internal representation of the motor vertical. Note that this conclusion is not challenged by the fact that response variability is affected by the intake of anti-motion sickness drugs: 42,43 our participants did not take those drugs in either of the two compared conditions, E and E′.…”

Section: Discussionmentioning

confidence: 82%

The motor vertical in the absence of gravicentric cues

Bock

Bury

2020

npj Microgravity

View full text Add to dashboard Cite

When participants are asked to flip an omnidirectional switch "down", the direction of their responses depends mainly on gravicentric, less so on egocentric and least on visual cues about the vertical (Lackner and DiZio, Exp. Brain Res. 130:2−26, 2000). Here we evaluate response direction when gravicentric cues are not available. Participants flipped an omnidirectional switch "down" when gravito-inertial force acted orthogonally to the response plane on earth (session E), and when it was near zero during parabolic flights (session P). We found that the relative weight of visual cues was similar in both sessions, and it was similar to that in an earlier study where participants stood upright. Across all three data sets, the weight of visual cues averaged 0.09. The relative weight of egocentric cues was also similar in both sessions, averaging 0.87; however, it was significantly lower in the earlier study with upright participants, where it averaged 0.43. We further found that informative and noninformative tactile stimulation had no substantial effects on response direction, which suggests that the earlier reported anchoring effect of tactile signals for the perceived vertical may not extend to the motor vertical. We conclude that the absence of gravicentric cues is compensated by a higher weight of egocentric cues, but not by a higher weight of visual cues. As a consequence, astronauts, divers and persons who work on ground in a horizontal body posture may mishandle equipment because of their strong reliance on egocentric cues.

show abstract

“…Another limitation of this study is that postflight vestibular examinations were performed in some subjects who took meclizine or promethazine. These vestibular suppressants can impair vestibular perception and cause drowsiness, 20 affecting the results of the vestibular examination and limiting the applicability of assessing symptoms that might impede an astronaut’s ability to exit the vehicle unassisted after landing.…”

Section: Discussionmentioning

confidence: 99%

Neurovestibular Symptoms in Astronauts Immediately after Space Shuttle and International Space Station Missions

2017

View full text Add to dashboard Cite

Objectives(1) To assess vestibular changes and related sensorimotor difficulties, especially instability of posture and gait, among astronauts immediately after they return from space and to compare the effects experienced after short- and long-duration space missions. (2) To determine whether any difficulties experienced were severe enough to impair the astronauts’ ability to leave the spacecraft in the event of an emergency.Study DesignProspective cohort study.SettingNational Aeronautics and Space Administration’s Kennedy Space Center and Johnson Space Center.Subjects and MethodsFourteen crewmembers of 3 Space Shuttle missions that lasted about 1 week and 18 crewmembers of 8 International Space Station missions that lasted about 6 months were given brief vestibular examinations 1 to 5 hours after landing. These examinations focused on the presence of vestibular and motor coordination difficulties, as well as motion sickness and motion sensations. Standardized tests included the observation of abnormal eye movements, finger-to-nose pointing, standing up from a seated position, postural stability, and tandem gait.ResultsUnsteady walking and postural instabilities were observed after short- and long-duration missions. Motion sickness symptoms were observed after long-duration missions but not after short-duration missions. The symptom most frequently reported by the astronauts was an exaggerated perceived motion associated with sudden head movements during reentry and after landing.ConclusionThe severity of the observed abnormalities would limit the ability of crewmembers during the first 5 hours after landing and increase the time required to leave the spacecraft during this period.

show abstract

The Impact of Oral Promethazine on Human Whole-Body Motion Perceptual Thresholds

Cited by 31 publications

References 53 publications

Variability in the Vestibulo-Ocular Reflex and Vestibular Perception

Variability in the Vestibulo-Ocular Reflex and Vestibular Perception

The motor vertical in the absence of gravicentric cues

Neurovestibular Symptoms in Astronauts Immediately after Space Shuttle and International Space Station Missions

Contact Info

Product

Resources

About