Pathophysiology of motor functions in prolonged manned space flights

Kozlovskaya, I. B.; Kreidich, Yu. V.; Оганов, В. С.; Koserenko, O.P.

doi:10.1016/0094-5765(81)90079-5

Cited by 99 publications

(49 citation statements)

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“…When compared to preflight values, they found that on the 6th day after flight, less force was required to perturb posture, and both the time to recover from the perturbation and overall muscle activity following the perturbation increased. Similar changes were also reported in larger groups of subjects following other long duration missions, short duration missions, and microgravity simulation experiments [6,15,26,29]. On the basis of these studies, the authors concluded that support unloading played an important role in the genesis of postural ataxia in short duration (up to 30 days) exposure to real and simulated microgravity.…”

supporting

confidence: 63%

“…Recovery appeared to be related to mission length. Similar results were obtained early in the Russian program, where investigators used stabilogram recordings of (1) quiet standing with eyes open and eyes closed, (2) standing in the sharpened Romberg posture, and (3) standing with the head tilted either forward or backward [24][25][26]. Subsequent studies of postural stability during quiet stance before and after flight have employed more complex paradigms.…”

supporting

confidence: 51%

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Recovery of Postural Equilibrium Control following Spaceflight^a

Paloski¹,

Reschke

Black

et al. 1992

Annals of the New York Academy of Sciences

102

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Human sensory-motor systems have evolved to optimize coordinated body movements and posture control in the terrestrial gravitational field. The central nervous system (CNS) has developed neurosensory systems that monitor and process sensory inputs to assess the biomechanical state of the body (spatial orientation), and neuromotor systems that create, select, and issue motor commands to correct biomechanical state errors [1][2][3]. Neurosensory systems respond to the sudden loss of graviceptor (otolith) stimulation during spaceflight by remodeling the sensory information integration processes used to assess spatial orientation [4,5]. Also, neuromotor systems respond to the sudden loss of the static gravitational biomechanical load by modifying the repertoire of motor command strategies and synergies used for movement control [6]. These in-flight sensory-motor adaptations optimize neural control of movement in microgravity but, unfortunately, are maladaptive for the terrestrial gravitational field. Among the operationally relevant consequences of this maladaptation is a disruption in postural equilibrium control immediately after return to Earth [7].Terrestrial posture control systems develop to maintain biomechanical stability during normal lifetime activities. Early in life the CNS learns to maintain stable control of the body center of mass during quiet stance, as well as in anticipation of, or in response to, postural disturbances created by voluntary movements or external disturbances. To accomplish this, the CNS uses inputs from visual, vestibular, proprioceptive, and somatosensory receptors to assess the current biomechanical state of the body [1]. This state feedback is used in conjunction with internal models of body kinematics and dynamics [2] to determine the spatial orientation and relative stability of the body. Also, based on these determinations, the CNS selects and commands the most appropriate motor control strategies and synergies to return the body to the desired equilibrium state [3, 8].Sensory feedback is critical to posture control. Normally, the CNS continuously, and subconsciously, assesses the differences between the actual biomechanical state observed by the available sensory feedback systems and the desired biomechanical state generated by higher level brain centers. When the differences (errors) are small, closed loop control neuronal circuits may adjust the motor outputs to compensate. However, when the errors are large, an open loop control mode may be triggered. Based on previous experience as well as the magnitude, direction, and rate of change of the error state vector, the CNS selects a stereotyped response from its memorized repertoire. It then issues the set of motor commands encoded in this response memory, triggering predetermined muscles at predetermined latencies without regard for the concomitant sensory feedback. Following this open loop command volley, the CNS immediately resumes continuous assessment of the current biomechanical state.Motor performance and biomechanics a...

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supporting

confidence: 63%

supporting

confidence: 51%

Recovery of Postural Equilibrium Control following Spaceflight^a

Paloski¹,

Reschke

Black

et al. 1992

Annals of the New York Academy of Sciences

102

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“…Similar phenomena were seen after a 18-d Soyuz-9 mission [109,110]. Such effects were marked immediately after flight but were normalized after approximately 10 d. After 140 and 185 d of spaceflight, Kozlovskaya et al [105] found that the ratio of EMG amplitude to the perturbation force during standing posture was more than double compared to the pre-flight level. They also reported that the time taken for balance recovery after external disturbances increased, the thresholds of corrective EMG responses decreased, and the EMG amplitudes and duration were longer than before flight.…”

Section: Postural Stability and Locomotionmentioning

confidence: 62%

“…Microgravity results in significant changes to the physiological and biomechanical characteristics of an organism [105]. Perhaps the most pervasive change is the loss of sensory activities from the otolith organs and sensory receptors responding to loading produced by body weight under normal gravitational conditions.…”

Section: Postural Stability and Locomotionmentioning

confidence: 99%

Neuromuscular Adaptation to Microgravity Environment.

Ohira

2000

JJP

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The pattern of muscle activity influences the morphological, metabolic, and contractile properties of skeletal muscles. For example, the metabolic capacity of muscles is affected specifically by the type of exercise training [1][2][3]. Increased activity or over-loading by removing the synergists causes a compensatory hypertrophy [4][5][6][7][8][9][10][11]. Hypertrophy is also induced by the stretching of matured muscles in vivo [12,13] and cultured myotubes and fibroblasts [14][15][16][17]. Exercise-induced metabolic adaptation of muscles is lost when exercise training is stopped [18]. Further, muscle atrophy is induced by denervation [10,19], spinal cord transection [20], joint immobilization [21][22][23], tenotomy [24,25], spaceflight [26][27][28][29], and/or hindlimb suspension [29][30][31][32]. Most of these models are generally presumed to be models of reduced neuromuscular activity. But the level of use may not be the only factor involved in the atrophic process.There is a close association in the physiological, biochemical, and morphological properties between a motoneuron and the muscle fibers it innervates [1]. Studies to support this view are those in which chronic electrical stimulation at low frequency (1-10 Hz) changes the properties of fast-twitch muscles toward those of slow-twitch muscles [33][34][35][36][37][38].Some of the characteristics of muscle fibers are also altered following cross-innervation [39][40][41][42]. Buller et al. [40] suggested that the neural influence on muscle could be due to neurotrophic effect as well as via nerve impulses. Muscular Responses to Gravitational Unloading Morphological propertiesGravitational unloading by exposure to weightlessness [26][27][28][29][43][44][45][46][47] and/or its simulation model, hindlimb suspension [29][30][31][32][48][49][50][51][52][53][54][55][56], causes rapid atrophy in muscles, such as soleus and adductor longus, that are composed predominantly of slow fibers. The cross-sectional areas (CSAs) of both slow-and fasttwitch fibers of rats were less after 14 d of spaceflight and hindlimb suspension than those in the agematched controls [29]. But the degree of atrophy was greater in slow-than fast-twitch fibers [28,29]. Therefore, muscles composed of predominantly slow fibers are more susceptible to atrophy [26,28, 47]. The weights of fast-twitch ankle dorsi-flexors, such as the tibialis anterior (TA) and extensor digitorum longus (EDL), are also generally less after unloading than those of age-matched controls [31, 57]. But these were Japanese Journal of Physiology, 50, 303-314, 2000 Key words: atrophy, fiber-type transformation, contractile properties, neural responses, microgravity.Abstract: Morphological and/or functional characteristics of skeletal muscles have a greater adaptability in response to changes in environmental stimuli. For example, an atrophy associated with a shift of fiber characteristics toward fast-twitch type is a common adaptation of antigravity muscle to a microgravity environment. Neuromuscular responses and ...

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“…This re-adaptation process is often accompanied by varying degrees of gait ataxia [16][17][18][19][20]. We are exploring the use of gait adaptability training as a countermeasure to mitigate the effects of microgravity exposure on locomotion.…”

Section: Discussionmentioning

confidence: 99%

Strategies of healthy adults walking on a laterally oscillating treadmill

2009

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Abstract:We mounted a treadmill on top of a six degree-of-freedom motion base platform to investigate locomotor responses produced by healthy adults introduced to a dynamic walking surface. The experiment examined self-selected strategies employed by participants when exposed to continuous, sinusoidal lateral motion of the support surface while walking. Torso translation and step width were used to classify responses used to stabilize gait in a novel, dynamic environment. Two response categories emerged. Participants tended to either fix themselves in space (FIS), allowing the treadbelt to move laterally beneath them, or they fixed themselves to the base (FTB), moving laterally as the motion base oscillated. The degree of fixation in both extremes varied across participants. This finding suggests that normal adults have innate and varied preferences for reacquiring gait stability, some depending more heavily on vision (FIS group) and others on proprioception (FTB group).

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Pathophysiology of motor functions in prolonged manned space flights

Cited by 99 publications

References 0 publications

Recovery of Postural Equilibrium Control following Spaceflight^a

Recovery of Postural Equilibrium Control following Spaceflight^a

Neuromuscular Adaptation to Microgravity Environment.

Strategies of healthy adults walking on a laterally oscillating treadmill

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Pathophysiology of motor functions in prolonged manned space flights

Cited by 99 publications

References 0 publications

Recovery of Postural Equilibrium Control following Spaceflighta

Recovery of Postural Equilibrium Control following Spaceflighta

Neuromuscular Adaptation to Microgravity Environment.

Strategies of healthy adults walking on a laterally oscillating treadmill

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Recovery of Postural Equilibrium Control following Spaceflight^a

Recovery of Postural Equilibrium Control following Spaceflight^a