Perceptual responses to linear acceleration after spaceflight: human neurovestibular studies on SLS-2

1996 ◽  
Vol 81 (1) ◽  
pp. 58-68 ◽  
Author(s):  
D. M. Merfeld ◽  
K. A. Polutchko ◽  
K. Schultz
Keyword(s):  
Response Latency ◽  
Life Sciences ◽  
Linear Acceleration ◽  
Microgravity Environment ◽  
Adaptive Changes ◽  
Before And After ◽  
Self Motion ◽  
Inertial Cues

Perceptual responses of four astronauts were measured before and after a 14-day Spacelab Life Sciences-2 mission during interaural (y-axis) and rostrocaudal (z-axis) linear acceleration to measure adaptive changes in perceptual responses to inertial cues. In one test, subjects used a joystick to null a pseudorandom velocity disturbance. Postflight, two of three subjects showed a significantly enhanced ability to null linear self-motion in the y-axis and z-axis orientations. In another test, the subjects used a joystick to indicate their direction of motion during a series of low-acceleration steps. The postflight responses of three of the four subjects showed a significant increase in the response latency for both y-axis and z-axis orientations. In a third test, subjects were asked to track a stationary but unseen target with their eyes while they translated linearly in the dark. No significant changes were observed in the postflight responses. The observed changes, when present, may be due to a reinterpretation of inertial cues that are functionally adaptive for the microgravity environment but are not optimal for responses on Earth.

scholarly journals Integration of visual and inertial cues in perceived heading of self-motion

2010 ◽  
Vol 10 (12) ◽  
pp. 1-1 ◽  
Author(s):  
K. N. de Winkel ◽  
J. Weesie ◽  
P. J. Werkhoven ◽  
E. L. Groen
Keyword(s):  
Self Motion ◽  
Inertial Cues

Disruption of postural readaptation by inertial stimuli following space flight*

1999 ◽  
Vol 9 (5) ◽  
pp. 369-378 ◽  
Author(s):  
F. Owen Black ◽  
William H. Paloski ◽  
Millard F. Reschke ◽  
Makoto Igarashi ◽  
Fred Guedry ◽  
...  
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Linear Acceleration ◽  
Postural Instability ◽  
Otolith Organs ◽  
Plane Rotation ◽  
Rotation Test ◽  
Normal Limits ◽  
Before And After ◽  
Recovery Trajectory

Postural instability (relative to pre-flight) has been observed in all shuttle astronauts studied upon return from orbital missions. Postural stability was more closely examined in four shuttle astronaut subjects before and after an 8 day orbital mission. Results of the pre- and post- flight postural stability studies were compared with a larger ( n = 34) study of astronauts returning from shuttle missions of similar duration. Results from both studies indicated that inadequate vestibular feedback was the most significant sensory deficit contributing to the postural instability observed post flight. For two of the four IML-1 astronauts, post-flight postural instability and rate of recovery toward their earth-normal performance matched the performance of the larger sample. However, post-flight postural control in one returning astronaut was substantially below mean performance. This individual, who was within normal limits with respect to postural control before the mission, indicated that recovery to pre-flight postural stability was also interrupted by a post-flight pitch plane rotation test. A similar, though less extreme departure from the mean recovery trajectory was present in another astronaut following the same post-flight rotation test. The pitch plane rotation stimuli included otolith stimuli in the form of both transient tangential and constant centripetal linear acceleration components. We inferred from these findings that adaptation on orbit and re-adaptation on earth involved a change in sensorimotor integration of vestibular signals most likely from the otolith organs.

scholarly journals Multiple Sensory Cues Underlying the Perception of Translation and Path

2007 ◽  
Vol 97 (2) ◽  
pp. 1100-1113 ◽  
Author(s):  
N. Au Yong ◽  
G. D. Paige ◽  
S. H. Seidman
Keyword(s):  
Sudden Change ◽  
Sensory Information ◽  
Stimulus Frequency ◽  
Linear Acceleration ◽  
Low Frequencies ◽  
Motion Cues ◽  
High Frequencies ◽  
Shift Experiment ◽  
Self Motion ◽  
Motion Profile

The translational linear vestibuloocular reflex compensates most accurately for high frequencies of head translation, with response magnitude decreasing with declining stimulus frequency. However, studies of the perception of translation typically report robust responses even at low frequencies or during prolonged motion. This inconsistency may reflect the incorporation of nondirectional sensory information associated with the vibration and noise that typically accompany translation, into motion perception. We investigated the perception of passive translation in humans while dissociating nondirectional cues from actual head motion. In a cue-dissociation experiment, interaural (IA) motion was generated using either a linear sled, the mechanics of which generated noise and vibration cues that were correlated with the motion profile, or a multiaxis technique that dissociated these cues from actual motion. In a trajectory-shift experiment, IA motion was interrupted by a sudden change in direction (±30° diagonal) that produced a change in linear acceleration while maintaining sled speed and therefore mechanical (nondirectional) cues. During multi-axis cue-dissociation trials, subjects reported erroneous translation perceptions that strongly reflected the pattern of nondirectional cues, as opposed to nearly veridical percepts when motion and nondirectional cues coincided. During trajectory-shift trials, subjects' percepts were initially accurate, but erroneous following the direction change. Results suggest that nondirectional cues strongly influence the perception of linear motion, while the utility of cues directly related to translational acceleration is limited. One key implication is that “path integration” likely involves complex mechanisms that depend on nondirectional and contextual self-motion cues in support of limited and transient otolith-dependent acceleration input.

Influences of Vitamin A and E Supplementation on Haematological, Functional and Oxidative Balance Parameters on Handball Players

2018 ◽  
Vol 69 (2) ◽  
pp. 332-336
Author(s):  
Dana Badau ◽  
Adela Badau ◽  
Florin Paraschiv ◽  
Liliana Marcela Rogozea ◽  
Hamida Al Hussein ◽  
...  
Keyword(s):  
Vitamin A ◽  
Aerobic Exercise ◽  
Physical Training ◽  
Antioxidant Effect ◽  
Haematological Parameters ◽  
Adaptive Changes ◽  
Functional Parameters ◽  
Oxidative Balance ◽  
Before And After ◽  
Pros And Cons

The objective of this study was to evaluate the antioxidant effect of the vitamins A and E before and after intensive aerobic exercise effort and to provide pros and cons arguments on the use of both vitamins during the physical training. The research highlighted important adaptive changes of the functional parameters: PMA, VCEE, VO2max, of the oxidative balance: LPx, MDA, as well as the haematological parameters: HGB, CRT, LYM, LAK.

Developing entrepreneurial competences in students in the life sciences: the Lifetech Ad-Venture program

2014 ◽  
Vol 22 (3) ◽  
pp. 182-191 ◽  
Author(s):  
Rafael Alcaraz-Rodriguez ◽  
Mario M. Alvarez ◽  
Marcia Villasana
Keyword(s):  
Undergraduate Students ◽  
Latin American ◽  
Life Sciences ◽  
Private University ◽  
Future Research ◽  
University Campus ◽  
Content Type ◽  
American University ◽  
Entrepreneurial Characteristics ◽  
Before And After

Purpose – The purpose of this paper is to identify how an entrepreneurship program in the life-sciences impacts the development of their entrepreneurial skills and values in undergraduate students. Design/methodology/approach – A quantitative study was conducted at Tecnologico de Monterrey, a private university in Mexico. Questionnaires were administered to life-sciences students before and after the entrepreneurship course to analyze and identify the development of pre-defined entrepreneurial characteristics. Findings – Results indicate a positive and significant impact on several of the 13 entrepreneurial characteristics evaluated in the study (negotiation skills, need of achievement and initiative). Empirical insights gained in the study suggest that gender does not yield to differences in the degree of involvement in activities, and that previous entrepreneurship experience may contribute to enhanced engagement in the program. Research limitations/implications – The paper reports on students from one university campus. Future research should include students from other locations in the country. Practical implications – It is evident that university entrepreneurship programs have an impact on students' skills and values; however, the challenge still remains in the design of those programs to include more activities and draw on the students' own competences. Originality/value – This paper contributes with evidence from an entrepreneurship program implemented in a Latin American university, a region for which documentation of the degree of success of entrepreneurship education is limited in the literature.

Decision Time and Movement Time in Depression: Differential Effects of Practice before and after Clinical Improvement

1989 ◽  
Vol 68 (1) ◽  
pp. 187-192 ◽  
Author(s):  
A. Ghozlan ◽  
D. Widlöcher
Keyword(s):  
Reaction Time ◽  
Clinical Improvement ◽  
Choice Reaction Time ◽  
Response Latency ◽  
Significant Variation ◽  
Movement Time ◽  
Decision Time ◽  
Clinical Recovery ◽  
Significant Difference ◽  
Before And After

Choice reaction time involves, at least two components of response latency, decision time and movement time. Studies of choice reaction time usually provide values of these two components averaged over a given number of trials. The aim of the present study of depressed subjects was to investigate changes across practice on Decision Time (DT) and Movement Time (MT) before and after clinical improvement. 19 depressed subjects were given two sessions of 50 trials each, one before treatment (Di) and one after recovery (Df). Decision time and movement time exhibited quite different patterns. Decision time significantly decreased with clinical improvement. No significant variation across trials was found, in either session. Movement time values varied across trials but the variations observed on Di and Df were significantly different, whereas before treatment latencies recorded at the end of the session were greater than those scored at the start, the contrary was observed after clinical recovery. No significant difference was found between values of movement time scored at the start of the two sessions.

scholarly journals Simple spike dynamics of Purkinje cells in the macaque vestibulo-cerebellum during passive whole-body self-motion

2020 ◽  
Vol 117 (6) ◽  
pp. 3232-3238
Author(s):  
Jean Laurens ◽  
Dora E. Angelaki
Keyword(s):  
Linear Acceleration ◽  
Cell Types ◽  
Whole Body ◽  
Otolith Organs ◽  
Response Dynamics ◽  
Position Signal ◽  
Selective Population ◽  
Body Self ◽  
Motor Actions ◽  
Self Motion

Theories of cerebellar functions posit that the cerebellum implements internal models for online correction of motor actions and sensory estimation. As an example of such computations, an internal model resolves a sensory ambiguity where the peripheral otolith organs in the inner ear sense both head tilts and translations. Here we exploit the response dynamics of two functionally coupled Purkinje cell types in the vestibular part of the caudal vermis (lobules IX and X) to understand their role in this computation. We find that one population encodes tilt velocity, whereas the other, translation-selective, population encodes linear acceleration. We predict that an intermediate neuronal type should temporally integrate the output of tilt-selective cells into a tilt position signal.

scholarly journals Football Players' Head-Impact Exposure After Limiting of Full-Contact Practices

2016 ◽  
Vol 51 (7) ◽  
pp. 511-518 ◽  
Author(s):  
Steven P. Broglio ◽  
Richelle M. Williams ◽  
Kathryn L. O'Connor ◽  
Jason Goldstick
Keyword(s):  
High School ◽  
Linear Acceleration ◽  
Head Impact ◽  
Football Players ◽  
High School Football ◽  
Cross Sectional ◽  
Full Contact ◽  
Rule Change ◽  
Before And After

Context: Sporting organizations limit full-contact football practices to reduce concussion risk and based on speculation that repeated head impacts may result in long-term neurodegeneration. Objective: To directly compare head-impact exposure in high school football players before and after a statewide restriction on full-contact practices. Design: Cross-sectional study. Setting: High school football field. Patients or Other Participants: Participants were varsity football athletes from a single high school. Before the rule change, 26 athletes (age = 16.2 ± 0.8 years, height = 179.6 ± 6.4 cm, weight = 81.9 ± 13.1 kg) participated. After the rule change, 24 athletes (age = 15.9 ± 0.8 years, height = 178.3 ± 6.5 cm, weight = 76.2 ± 11.6 kg) participated. Nine athletes participated in both years of the investigation. Main Outcome Measure(s): Head-impact exposure was monitored using the Head Impact Telemetry System while the athletes participated in football games and practices in the seasons before and after the rule change. Head-impact frequency, location, and magnitude (ie, linear acceleration, rotational acceleration, and Head Impact Telemetry severity profile [HITsp], respectively) were measured. Results: A total of 15 398 impacts (592 impacts per player per season) were captured before the rule change and 8269 impacts (345 impacts per player per season) after the change. An average 42% decline in impact exposure occurred across all players, with practice-exposure declines occurring among linemen (46% decline); receivers, cornerbacks, and safeties (41% decline); and tight ends, running backs (including fullbacks), and linebackers (39% decline). Impact magnitudes remained largely unchanged between the years. Conclusions: A rule change limiting full-contact high school football practices appears to have been effective in reducing head-impact exposure across all players, with the largest reduction occurring among linemen. This finding is likely associated with the rule modification, particularly because the coaching staff and offensive scheme remained consistent, yet how this reduction influences concussion risk and long-term cognitive health remains unknown.

Space Sled—a Device for the Investigation of the Physiological Effects of Weightlessness

1989 ◽  
Vol 203 (1) ◽  
pp. 1-10 ◽  
Author(s):  
N A J Harry ◽  
A J Benson
Keyword(s):  
Peak Velocity ◽  
Linear Acceleration ◽  
Test Subject ◽  
Microgravity Environment ◽  
Physiological Effects ◽  
Peak Acceleration ◽  
Otolith Organ ◽  
Steel Cable ◽  
System A ◽  
Working Section

Space Sled is a device for providing controlled linear acceleration stimuli in the microgravity environment of orbital flight. The scientific objectives of the experiments which used Space Sled on the D-1 Spacelab mission were to study aspects of otolith organ (that is, that part of the inner ear which transduces linear accelerations) function and adaptation in weightlessness. Space Sled comprises electrical and mechanical sub-systems. The latter is made up of a carriage running on twin rails that are fixed to the floor of Spacelab. The assembly is 6 m long with a working section of 3.5 m. The seat accommodating the test subject can be mounted on the carriage in any of three orthogonal positions. The carriage is coupled by a flexible steel cable to a servo-controlled electric motor which is capable of producing a peak acceleration of 2 m/s2 and peak velocity of 2.4 m/s. In the event of failure of comprehensive safety circuits in the electrical sub-system, a mechanical snubber, of crushable honeycomb construction, limits the deceleration to 20 m/s2. Mechanical structures providing carriage guidance, Sled/Spacelab interfaces, carriage latching, motor mounting and cable tensioning are detailed in the paper.

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