scholarly journals Adaptation after vastus lateralis denervation in rats suggests neural regulation of joint stresses and strains

2018 ◽  
Author(s):  
Cristiano Alessando ◽  
Benjamin A. Rellinger ◽  
Filipe O. Barroso ◽  
Matthew C. Tresch
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Task Performance ◽  
Neural Control ◽  
Muscle Force ◽  
Vastus Lateralis ◽  
Adaptation Strategies ◽  
Internal Joint ◽  
The Central Nervous System ◽  
Muscle Activations

AbstractIn order to produce movements, muscles must act through joints. The translation from muscle force to limb movement is mediated by internal joint structures that permit movement in some directions but constrain it in others. Although muscle forces acting against constrained directions will not affect limb movements, such forces can cause excess stresses and strains in joint structures, leading to pain or injury. In this study, we hypothesized that the central nervous system (CNS) chooses muscle activations to avoid excess joint stresses and strains. We evaluated this hypothesis by examining adaptation strategies after selective paralysis of a muscle acting at the rat knee. We show that the CNS compromises between restoration of task performance and regulation of joint stresses and strains. These results have significant implications to our understanding of the neural control of movements, suggesting that common theories emphasizing task performance are insufficient to explain muscle activations during behaviors.

scholarly journals Adaptation after vastus lateralis denervation in rats demonstrates neural regulation of joint stresses and strains

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Cristiano Alessandro ◽  
Benjamin A Rellinger ◽  
Filipe Oliveira Barroso ◽  
Matthew C Tresch
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Task Performance ◽  
Neural Control ◽  
Muscle Force ◽  
Vastus Lateralis ◽  
Adaptation Strategies ◽  
Internal Joint ◽  
The Central Nervous System ◽  
Muscle Activations

In order to produce movements, muscles must act through joints. The translation from muscle force to limb movement is mediated by internal joint structures that permit movement in some directions but constrain it in others. Although muscle forces acting against constrained directions will not affect limb movements, such forces can cause excess stresses and strains in joint structures, leading to pain or injury. In this study, we hypothesized that the central nervous system (CNS) chooses muscle activations to avoid excessive joint stresses and strains. We evaluated this hypothesis by examining adaptation strategies after selective paralysis of a muscle acting at the rat’s knee. We show that the CNS compromises between restoration of task performance and regulation of joint stresses and strains. These results have significant implications to our understanding of the neural control of movements, suggesting that common theories emphasizing task performance are insufficient to explain muscle activations during behaviors.

scholarly journals Adaptation of muscle activation after patellar loading demonstrates neural control of joint variables

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Filipe O. Barroso ◽  
Cristiano Alessandro ◽  
Matthew C. Tresch
Keyword(s):  
Neural Control ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Lateral Force ◽  
Vastus Medialis ◽  
Internal Joint ◽  
Before And After ◽  
The Central Nervous System ◽  
Muscle Activations

AbstractWe evaluated whether the central nervous system (CNS) chooses muscle activations not only to achieve behavioral goals but also to minimize stresses and strains within joints. We analyzed the coordination between quadriceps muscles during locomotion in rats before and after imposing a lateral force on the patella. Vastus lateralis (VL) and vastus medialis (VM) in the rat produce identical knee torques but opposing mediolateral patellar forces. If the CNS regulates internal joint stresses, we predicted that after imposing a lateral patellar load by attaching a spring between the patella and lateral femur, the CNS would reduce the ratio between VL and VM activation to minimize net mediolateral patellar forces. Our results confirmed this prediction, showing that VL activation was reduced after attaching the spring whereas VM and rectus femoris (RF) activations were not significantly changed. This adaptation was reversed after the spring was detached. These changes were not observed immediately after attaching the spring but only developed after 3–5 days, suggesting that they reflected gradual processes rather than immediate compensatory reflexes. Overall, these results support the hypothesis that the CNS chooses muscle activations to regulate internal joint variables.

scholarly journals On The Hormonal and Neural Control of the Release of Gametes in Ascidians

1951 ◽  
Vol 28 (4) ◽  
pp. 463-472
Author(s):  
D. B. CARLISLE
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Control ◽  
Sense Organ ◽  
Chorionic Gonadotrophin ◽  
Gamete Release ◽  
The Central Nervous System ◽  
Neural Region

1. It is argued that the neural gland (+ciliated pit) of ascidians is homologous with the entire pituitary of vertebrates, adenohypophysis as well as neurohypophysis. 2. Ciona and Phallusia are shown to respond to an injection of chorionic gonadotrophin by the release of gametes. 3. They respond in the same way to feeding with eggs and sperm of their own species but not to those of other species. 4. This response is prevented in both cases by section of the nerves from the ganglion to the region of the gonads. 5. Destruction of the heart and removal of the blood does not prevent the response to feeding with gametes, nor to injection of gonadotrophin into the neural region; this operation does prevent the reaction if the site of injection is elsewhere. 6. Destruction of the neural gland, leaving the ganglion intact, prevents the response to feeding with gametes, but does not prevent its following an injection of chorionic gonadotrophin. 7. The hypothesis is advanced that the neural gland (+ciliated pit) is the sense organ involved in this response to feeding, and that it produces gonadotrophin and passes it to the ganglion by a non-vascular route; the ganglion then stimulates by nervous pathways the gonads to release gametes. 8. It is suggested that gonadotrophin is here fulfilling a sensory role in passing information from sense organ to the central nervous system. It may be contrasted with adrenalin which passes instructions from the central nervous system to effectors. 9. Phallusia is shown to respond with gamete release to an injection of an extract of the neural complex of Ciona.

scholarly journals Manifold reaching paradigm: how do we handle target redundancy?

2011 ◽  
Vol 106 (4) ◽  
pp. 2086-2102 ◽  
Author(s):  
Bastien Berret ◽  
Enrico Chiovetto ◽  
Francesco Nori ◽  
Thierry Pozzo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Degrees Of Freedom ◽  
A Priori ◽  
Movement Planning ◽  
Optimal Feedback Control ◽  
Target Redundancy ◽  
The Central Nervous System ◽  
Point To Point ◽  
Muscle Activations

How the central nervous system coordinates the many intrinsic degrees of freedom of the musculoskeletal system is a recurrent question in motor control. Numerous studies addressed it by considering redundant reaching tasks such as point-to-point arm movements, for which many joint trajectories and muscle activations are usually compatible with a single goal. There exists, however, a different, extrinsic kind of redundancy that is target redundancy. Many times, indeed, the final point to reach is neither specified nor unique. In this study, we aim to understand how the central nervous system tackles such an extrinsic redundancy by considering a reaching-to-a-manifold paradigm, more specifically an arm pointing to a long vertical bar. In this case, the endpoint is not defined a priori and, therefore, subjects are free to choose any point on the bar to successfully achieve the task. We investigated the strategies used by subjects to handle this presented choice. Our results indicate both intersubject and intertrial consistency with respect to the freedom provided by the task. However, the subjects' behavior is found to be more variable than during classical point-to-point reaches. Interestingly, the average arm trajectories to the bar and the structure of intertrial endpoint variations could be explained via stochastic optimal control with an energy/smoothness expected cost and signal-dependent motor noise. We conclude that target redundancy is first overcome during movement planning and then exploited during movement execution, in agreement with stochastic optimal feedback control principles, which illustrates how the complementary problems of goal and movement selection may be resolved at once.

scholarly journals Accuracy of Force Repeatability in Relation to its Value and the Subjects’ Sex

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
Ryszard Błacha ◽  
Agnieszka D. Jastrzębska
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sex Differences ◽  
Muscle Force ◽  
Force Generation ◽  
Male Students ◽  
Minor Influence ◽  
The Central Nervous System ◽  
A Minor ◽  
Voluntary Contractions

AbstractThe purpose of the study was to determine the influence of force value and sex on force generation repeatability.The total of 17 female and 24 male students performed 3 maximal voluntary contractions for maximal force (FThe force generation repeatability rose with the increase of triggered force in both sexes; between force target 49 N vs. 98 N and 147 N (The influence of force value and a minor influence of sex on accuracy in generated forces might suggest that the control of muscle force by the central nervous system is similar in both sexes and the sex differences in muscle force generations are rather of muscle mass and structure.

Neural Control of the Male Photuris Versicolor Firefly Flash

1981 ◽  
Vol 92 (1) ◽  
pp. 165-172
Author(s):  
ALBERT D. CARLSON
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Control ◽  
Ventral Nerve Cord ◽  
Temperature Coefficients ◽  
Wide Range ◽  
The Central Nervous System ◽  
Oscillatory Character ◽  
Lower Temperature ◽  
Stimulation Of

1. Continuous electrical stimulation of the ventral nerve cord or the lantern of the decapitated male Photuris versicolor firefly over a wide range of stimulus frequencies can produce a flash that is multi-peaked, like the courtship flash of this species. The central nervous system does not shape these stimulated compound flashes because they can be induced in deganglionated posterior lantern segments. 2. The stimulated compound flashes show a fixed oscillatory character with peak frequencies independent of stimulation frequency. They can be generated by individual lantern areas. Compared with the peaks of courtship flashes the peaks of stimulated flashes show higher frequency, significantly lower temperature coefficients (Q)10, and incomplete extinction. 3. P. lucicrescens males produce a courtship flash that has a single peak and their lanterns respond to continuous stimulation with an unstructured glow.

scholarly journals Central nervous system modulates the neuromechanical delay in a broad range for the control of muscle force

2018 ◽  
Vol 125 (5) ◽  
pp. 1404-1410 ◽  
Author(s):  
A. Del Vecchio ◽  
A. Úbeda ◽  
M. Sartori ◽  
J. M. Azorín ◽  
F. Felici ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Motor Unit ◽  
Neural Coding ◽  
Neural Control ◽  
Motor Units ◽  
Force Generation ◽  
Neural Drive ◽  
Wide Range ◽  
The Central Nervous System

Force is generated by muscle units according to the neural activation sent by motor neurons. The motor unit is therefore the interface between the neural coding of movement and the musculotendinous system. Here we propose a method to accurately measure the latency between an estimate of the neural drive to muscle and force. Furthermore, we systematically investigate this latency, which we refer to as the neuromechanical delay (NMD), as a function of the rate of force generation. In two experimental sessions, eight men performed isometric finger abduction and ankle dorsiflexion sinusoidal contractions at three frequencies and peak-to-peak amplitudes {0.5, 1, and 1.5 Hz; 1, 5, and 10 of maximal force [%maximal voluntary contraction (MVC)]}, with a mean force of 10% MVC. The discharge timings of motor units of the first dorsal interosseous (FDI) and tibialis anterior (TA) muscle were identified by high-density surface EMG decomposition. The neural drive was estimated as the cumulative discharge timings of the identified motor units. The neural drive predicted 80 ± 0.4% of the force fluctuations and consistently anticipated force by 194.6 ± 55 ms (average across conditions and muscles). The NMD decreased nonlinearly with the rate of force generation ( R2 = 0.82 ± 0.07; exponential fitting) with a broad range of values (from 70 to 385 ms) and was 66 ± 0.01 ms shorter for the FDI than TA ( P < 0.001). In conclusion, we provided a method to estimate the delay between the neural control and force generation, and we showed that this delay is muscle-dependent and is modulated within a wide range by the central nervous system. NEW & NOTEWORTHY The motor unit is a neuromechanical interface that converts neural signals into mechanical force with a delay determined by neural and peripheral properties. Classically, this delay has been assessed from the muscle resting level or during electrically elicited contractions. In the present study, we introduce the neuromechanical delay as the latency between the neural drive to muscle and force during variable-force contractions, and we show that it is broadly modulated by the central nervous system.

Vagovagal reflex control of digestion: afferent modulation by neural and "endoneurocrine" factors

1995 ◽  
Vol 268 (1) ◽  
pp. G1-G10 ◽  
Author(s):  
R. C. Rogers ◽  
D. M. McTigue ◽  
G. E. Hermann
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Brain Stem ◽  
Neural Control ◽  
Dorsal Vagal Complex ◽  
The Central Nervous System ◽  
Small Intestinal ◽  
Reflex Control ◽  
Control Circuits ◽  
The Brain

Vagovagal reflex control circuits in the dorsal vagal complex of the brain stem provide overall coordination of gastric, small intestinal, and pancreatic digestive functions. The neural components forming these reflex circuits are under substantial descending neural control. By adjusting the excitability of the differing components of the reflex, significant alterations in digestion control can be produced by the central nervous system. Additionally, the dorsal vagal complex is situated within a circumventricular region without a "blood-brain barrier." As a result, vagovagal reflex circuitry is also exposed to humoral influences, which can profoundly alter digestive functions by acting directly on brain stem neurons.

scholarly journals Flexible recruitments of fundamental muscle synergies in the trunk and lower limbs for highly variable movements and postures

2021 ◽  
Author(s):  
Hiroki Saito ◽  
Hikaru Yokoyama ◽  
Atsushi Sasaki ◽  
Tatsuya Kato ◽  
Kimitaka Nakazawa
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Control ◽  
Static Stability ◽  
Neural Representation ◽  
Lower Limbs ◽  
Muscle Synergies ◽  
Lower Limb Muscles ◽  
The Central Nervous System ◽  
Almost All

The extent to which muscle synergies represent the neural control of human behavior remains unknown. Here, we tested whether certain sets of muscle synergies that are fundamentally necessary across behaviors exist. We measured the electromyographic activities of 26 muscles including bilateral trunk and lower limb muscles during 24 locomotion, dynamic and static stability tasks, and extracted the muscle synergies using non-negative matrix factorization. Our results showed that 13 muscle synergies that may have unique functional roles accounted for almost all 24 tasks by combinations of single and/or merging of synergies. Therefore, our results may support the notion of the low dimensionality in motor outputs, in which the central nervous system flexibly recruits fundamental muscle synergies to execute diverse human behaviors. Further studies using manipulations of the central nervous system and/or neural recording are required the neural representation with such fundamental components of muscle synergies.

Insights into the neural control of eccentric contractions

2014 ◽  
Vol 116 (11) ◽  
pp. 1418-1425 ◽  
Author(s):  
Jacques Duchateau ◽  
Stéphane Baudry
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Control ◽  
Current Knowledge ◽  
Discharge Rate ◽  
Voluntary Activation ◽  
Eccentric Contractions ◽  
Future Research ◽  
Neural Activation ◽  
The Central Nervous System

The purpose of this brief review is to examine our current knowledge of the neural control of eccentric contractions. The review focuses on three main issues. The first issue considers the ability of individuals to activate muscles maximally during eccentric contractions. Most studies indicate that, regardless of the experimental approach (surface EMG amplitude, twitch superimposition, and motor unit recordings), it is usually more difficult to achieve full activation of a muscle by voluntary command during eccentric contractions than during concentric and isometric contractions. The second issue is related to the specificity of the control strategy used by the central nervous system during submaximal eccentric contractions. This part underscores that although the central nervous system appears to employ a single size-related strategy to activate motoneurons during the different types of contractions, the discharge rate of motor units is less during eccentric contractions across different loading conditions. The last issue addresses the mechanisms that produce this specific neural activation. This section indicates that neural adjustments at both supraspinal and spinal levels contribute to the specific modulation of voluntary activation during eccentric contractions. Although the available information on the control of eccentric contractions has increased during the last two decades, this review indicates that the exact mechanisms underlying the unique neural modulation observed in this type of contraction at spinal and supraspinal levels remains unknown and their understanding represents, therefore, a major challenge for future research on this topic.

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