Effects of Simulated Microgravity and Hypergravity Conditions on Arm Movements in Normogravity

The human sensorimotor control has evolved in the Earth’s environment where all movement is influenced by the gravitational force. Changes in this environmental force can severely impact the performance of arm movements which can be detrimental in completing certain tasks such as piloting or controlling complex vehicles. For this reason, subjects that are required to perform such tasks undergo extensive training procedures in order to minimize the chances of failure. We investigated whether local gravity simulation of altered gravitational conditions on the arm would lead to changes in kinematic parameters comparable to the full-body experience of microgravity and hypergravity onboard a parabolic flight. To see if this would be a feasible approach for on-ground training of arm reaching movements in altered gravity conditions we developed a robotic device that was able to apply forces at the wrist in order to simulate micro- or hypergravity conditions for the arm while subjects performed pointing movements on a touch screen. We analyzed and compared the results of several kinematic parameters along with muscle activity using this system with data of the same subjects being fully exposed to microgravity and hypergravity conditions on a parabolic flight. Both in our simulation and in-flight, we observed a significant increase in movement durations in microgravity conditions and increased velocities in hypergravity for upward movements. Additionally, we noted a reduced accuracy of pointing both in-flight and in our simulation. These promising results suggest, that locally simulated altered gravity can elicit similar changes in some movement characteristics for arm reaching movements. This could potentially be exploited as a means of developing devices such as exoskeletons to aid in training individuals prior to undertaking tasks in changed gravitational conditions.

Download Full-text

Two functionally different synergies during arm reaching movements involving the trunk

Journal of Neurophysiology ◽

10.1152/jn.1995.73.5.2120 ◽

1995 ◽

Vol 73 (5) ◽

pp. 2120-2122 ◽

Cited By ~ 80

Author(s):

S. Ma ◽

A. G. Feldman

Keyword(s):

Motor Control ◽

Degrees Of Freedom ◽

Arm Movements ◽

The Other ◽

Reaching Movements ◽

Positional Error ◽

Trunk Motion ◽

Arm Reaching ◽

Trunk Movements ◽

The Right

1. To address the problem of the coordination of a redundant number of degrees of freedom in motor control, we analyzed the influence of voluntary trunk movements on the arm endpoint trajectory during reaching. 2. Subjects made fast noncorrected planar movements of the right arm from a near to a far target located in the ipsilateral work space at a 45 degrees angle to the sagittal midline of the trunk. These reaching movements were combined with a forward or a backward sagittal motion of the trunk. 3. The direction, positional error, curvature, and velocity profile of the endpoint trajectory remained invariant regardless of trunk movements. Trunk motion preceded endpoint motion by approximately 175 ms, continued during endpoint movement to the target, and outlasted it by 200 ms. This sequence of trunk and arm movements was observed regardless of the direction of the endpoint trajectory (to or from the far target) or trunk movements (forward or backward). 4. Our data imply that reaching movements result from two control synergies: one coordinates trunk and arm movements leaving the position of the endpoint unchanged, and the other produces interjoint coordination shifting the arm endpoint to the target. The use of functionally different synergies may underlie a solution of the redundancy problem.

Download Full-text

Distinct adaptation patterns between grip dynamics and arm kinematics when the body is upside-down

Journal of Neurophysiology ◽

10.1152/jn.00357.2020 ◽

2021 ◽

Vol 125 (3) ◽

pp. 862-874

Author(s):

L. Opsomer ◽

F. Crevecoeur ◽

J-L. Thonnard ◽

J. McIntyre ◽

P. Lefèvre

Keyword(s):

Reference Frames ◽

Parabolic Flight ◽

Arm Movements ◽

The Body ◽

Common Mechanism ◽

Altered Gravity ◽

Movement Kinematics ◽

Body Postures ◽

Arm Kinematics

During rhythmic arm movements performed in an upside-down posture, grip control adapted very quickly, but kinematics adaptation was more progressive. Our results suggest that grip control and movement kinematics planning might operate in different reference frames. Moreover, by comparing our results with previous results from parabolic flight studies, we propose that a common mechanism underlies adaptation to unfamiliar body postures and adaptation to altered gravity.

Download Full-text

Role of Non-Lesioned Hemisphere in Affected Arm Reaching Movements After Severe Stroke: A Pilot Study

Archives of Physical Medicine and Rehabilitation ◽

10.1016/j.apmr.2014.07.064 ◽

2014 ◽

Vol 95 (10) ◽

pp. e26

Author(s):

Sambit Mohapatra ◽

Evan Chan ◽

Rachael Harrington ◽

Alexander Dromerick ◽

Peter Turkeltaub ◽

...

Keyword(s):

Pilot Study ◽

Reaching Movements ◽

Severe Stroke ◽

Arm Reaching

Download Full-text

Feedback Control of Functional Electrical Stimulation for 2-D Arm Reaching Movements

IEEE Transactions on Neural Systems and Rehabilitation Engineering ◽

10.1109/tnsre.2018.2853573 ◽

2018 ◽

Vol 26 (10) ◽

pp. 2033-2043 ◽

Cited By ~ 7

Author(s):

Reza Sharif Razavian ◽

Borna Ghannadi ◽

Naser Mehrabi ◽

Mark Charlet ◽

John McPhee

Keyword(s):

Electrical Stimulation ◽

Feedback Control ◽

Functional Electrical Stimulation ◽

Reaching Movements ◽

Arm Reaching

Download Full-text

Transcriptional Homeostasis of Oxidative Stress-Related Pathways in Altered Gravity

International Journal of Molecular Sciences ◽

10.3390/ijms19092814 ◽

2018 ◽

Vol 19 (9) ◽

pp. 2814 ◽

Cited By ~ 6

Author(s):

Svantje Tauber ◽

Swantje Christoffel ◽

Cora Thiel ◽

Oliver Ullrich

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Immune System ◽

Cellular Response ◽

Cultured Cells ◽

Parabolic Flight ◽

Reactive Oxygen ◽

Oxygen Species ◽

Altered Gravity ◽

Human Immune System

Whereby several types of cultured cells are sensitive to gravity, the immune system belongs to the most affected systems during spaceflight. Since reactive oxygen species/reactive nitrogen species (ROS/RNS) are serving as signals of cellular homeostasis, particularly in the cells of the immune system, we investigated the immediate effect of altered gravity on the transcription of 86 genes involved in reactive oxygen species metabolism, antioxidative systems, and cellular response to oxidative stress, using parabolic flight and suborbital ballistic rocket experiments and microarray analysis. In human myelomonocytic U937 cells, we detected a rapid response of 19.8% of all of the investigated oxidative stress-related transcripts to 1.8 g of hypergravity and 1.1% to microgravity as early as after 20 s. Nearly all (97.2%) of the initially altered transcripts adapted after 75 s of hypergravity (max. 13.5 g), and 100% adapted after 5 min of microgravity. After the almost complete adaptation of initially altered transcripts, a significant second pool of differentially expressed transcripts appeared. In contrast, we detected nearly no response of oxidative stress-related transcripts in human Jurkat T cells to altered gravity. In conclusion, we assume a very well-regulated homeostasis and transcriptional stability of oxidative stress-related pathways in altered gravity in cells of the human immune system.

Download Full-text

Nanopore sequencing at Mars, Europa, and microgravity conditions

npj Microgravity ◽

10.1038/s41526-020-00113-9 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Christopher E. Carr ◽

Noelle C. Bryan ◽

Kendall N. Saboda ◽

Srinivasa A. Bhattaru ◽

Gary Ruvkun ◽

...

Keyword(s):

Parabolic Flight ◽

Space Station ◽

Space Vehicles ◽

Nanopore Sequencing ◽

Icy Moons ◽

Microbial Monitoring ◽

Oxford Nanopore ◽

Microgravity Conditions ◽

Low Mass ◽

Consistent Performance

Abstract Nanopore sequencing, as represented by Oxford Nanopore Technologies’ MinION, is a promising technology for in situ life detection and for microbial monitoring including in support of human space exploration, due to its small size, low mass (~100 g) and low power (~1 W). Now ubiquitous on Earth and previously demonstrated on the International Space Station (ISS), nanopore sequencing involves translocation of DNA through a biological nanopore on timescales of milliseconds per base. Nanopore sequencing is now being done in both controlled lab settings as well as in diverse environments that include ground, air, and space vehicles. Future space missions may also utilize nanopore sequencing in reduced gravity environments, such as in the search for life on Mars (Earth-relative gravito-inertial acceleration (GIA) g = 0.378), or at icy moons such as Europa (g = 0.134) or Enceladus (g = 0.012). We confirm the ability to sequence at Mars as well as near Europa or Lunar (g = 0.166) and lower g levels, demonstrate the functionality of updated chemistry and sequencing protocols under parabolic flight, and reveal consistent performance across g level, during dynamic accelerations, and despite vibrations with significant power at translocation-relevant frequencies. Our work strengthens the use case for nanopore sequencing in dynamic environments on Earth and in space, including as part of the search for nucleic-acid based life beyond Earth.

Download Full-text

Motor Cortex Neural Correlates of Output Kinematics and Kinetics During Isometric-Force and Arm-Reaching Tasks

Journal of Neurophysiology ◽

10.1152/jn.00989.2004 ◽

2005 ◽

Vol 94 (4) ◽

pp. 2353-2378 ◽

Cited By ~ 148

Author(s):

Lauren E. Sergio ◽

Catherine Hamel-Pâquet ◽

John F. Kalaska

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Isometric Force ◽

Arm Movements ◽

Population Level ◽

Emg Activity ◽

Hand Motion ◽

Arm Reaching ◽

Direction Of Movement ◽

Isometric Forces

We recorded the activity of 132 proximal-arm-related neurons in caudal primary motor cortex (M1) of two monkeys while they generated either isometric forces against a rigid handle or arm movements with a heavy movable handle, in the same eight directions in a horizontal plane. The isometric forces increased in monotonic fashion in the direction of the force target. The forces exerted against the handle in the movement task were more complex, including an initial accelerating force in the direction of movement followed by a transient decelerating force opposite to the direction of movement as the hand approached the target. EMG activity of proximal-arm muscles reflected the difference in task dynamics, showing directional ramplike activity changes in the isometric task and reciprocally tuned “triphasic” patterns in the movement task. The apparent instantaneous directionality of muscle activity, when expressed in hand-centered spatial coordinates, remained relatively stable during the isometric ramps but often showed a large transient shift during deceleration of the arm movements. Single-neuron and population-level activity in M1 showed similar task-dependent changes in temporal pattern and instantaneous directionality. The momentary dissociation of the directionality of neuronal discharge and movement kinematics during deceleration indicated that the activity of many arm-related M1 neurons is not coupled only to the direction and speed of hand motion. These results also demonstrate that population-level signals reflecting the dynamics of motor tasks and of interactions with objects in the environment are available in caudal M1. This task-dynamics signal could greatly enhance the performance capabilities of neuroprosthetic controllers.

Download Full-text

Reaching During Virtual Rotation: Context Specific Compensations for Expected Coriolis Forces

Journal of Neurophysiology ◽

10.1152/jn.2000.83.6.3230 ◽

2000 ◽

Vol 83 (6) ◽

pp. 3230-3240 ◽

Cited By ~ 44

Author(s):

Joseph V. Cohn ◽

Paul DiZio ◽

James R. Lackner

Keyword(s):

Target Location ◽

Arm Movements ◽

Open Loop ◽

Tactile Feedback ◽

Body Motion ◽

Reaching Movements ◽

Coriolis Forces ◽

Enclosed Chamber ◽

Path Curvature ◽

Context Specific

Subjects who are in an enclosed chamber rotating at constant velocity feel physically stationary but make errors when pointing to targets. Reaching paths and endpoints are deviated in the direction of the transient inertial Coriolis forces generated by their arm movements. By contrast, reaching movements made during natural, voluntary torso rotation seem to be accurate, and subjects are unaware of the Coriolis forces generated by their movements. This pattern suggests that the motor plan for reaching movements uses a representation of body motion to prepare compensations for impending self-generated accelerative loads on the arm. If so, stationary subjects who are experiencing illusory self-rotation should make reaching errors when pointing to a target. These errors should be in the direction opposite the Coriolis accelerations their arm movements would generate if they were actually rotating. To determine whether such compensations exist, we had subjects in four experiments make visually open-loop reaches to targets while they were experiencing compelling illusory self-rotation and displacement induced by rotation of a complex, natural visual scene. The paths and endpoints of their initial reaching movements were significantly displaced leftward during counterclockwise illusory rotary displacement and rightward during clockwise illusory self-displacement. Subjects reached in a curvilinear path to the wrong place. These reaching errors were opposite in direction to the Coriolis forces that would have been generated by their arm movements during actual torso rotation. The magnitude of path curvature and endpoint errors increased as the speed of illusory self-rotation increased. In successive reaches, movement paths became straighter and endpoints more accurate despite the absence of visual error feedback or tactile feedback about target location. When subjects were again presented a stationary scene, their initial reaches were indistinguishable from pre-exposure baseline, indicating a total absence of aftereffects. These experiments demonstrate that the nervous system automatically compensates in a context-specific fashion for the Coriolis forces associated with reaching movements.

Download Full-text

Contrasting Neuronal Activity in the Dorsal and Ventral Premotor Areas During Preparation to Reach

Journal of Neurophysiology ◽

10.1152/jn.00496.2001 ◽

2002 ◽

Vol 87 (2) ◽

pp. 1123-1128 ◽

Cited By ~ 57

Author(s):

Eiji Hoshi ◽

Jun Tanji

Keyword(s):

Neuronal Activity ◽

Target Location ◽

Delay Period ◽

Reaching Movements ◽

Target Acquisition ◽

Trigger Signal ◽

Arm Reaching ◽

Motor Set ◽

Premotor Areas

We compared neuronal activity in the dorsal and ventral premotor areas (PMd and PMv, respectively) when monkeys were preparing to perform arm-reaching movements in a motor-set period before their actual execution. They were required to select one of four possible movements (reaching to a target on the left or right, using either the left or right arm) in accordance with two sets of instruction cues, followed by a delay period, and a subsequent motor-set period. During the motor-set period, the monkeys were required to get ready for a movement-trigger signal to start the arm-reach promptly. We analyzed the activity of 211 PMd and 109 PMv neurons that showed selectivity for the combination of the two instruction cues during the motor-set period. A majority (53%) of PMd neurons exhibited activity significantly tuned to both target location and arm use, and an approximately equal number of PMd neurons showed selectivity to either forthcoming arm use or target location. In contrast, 60% of PMv neurons showed selectivity for target location only and not for arm use. These findings point to preference in the use of neuronal activity in the two areas: preparation for action in the PMd and preparation for target acquisition in the PMv.

Download Full-text