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Matthew C Tresch - One of the best experts on this subject based on the ideXlab platform.
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coordination amongst quadriceps muscles suggests Neural Regulation of internal joint stresses not simplification of task performance
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Cristiano Alessandro, Filipe O Barroso, Matthew C Tresch, Adarsh Prashara, David P Tentler, Hsin Yun YehAbstract:Many studies have demonstrated covariation between muscle activations during behavior, suggesting that muscles are not controlled independently. According to one common proposal, this covariation reflects simplification of task performance by the nervous system so that muscles with similar contributions to task variables are controlled together. Alternatively, this covariation might reflect Regulation of low-level aspects of movements that are common across tasks, such as stresses within joints. We examined these issues by analyzing covariation patterns in quadriceps muscle activity during locomotion in rats. The three monoarticular quadriceps muscles (vastus medialis [VM], vastus lateralis [VL], and vastus intermedius [VI]) produce knee extension and so have identical contributions to task performance; the biarticular rectus femoris (RF) produces an additional hip flexion. Consistent with the proposal that muscle covariation is related to similarity of muscle actions on task variables, we found that the covariation between VM and VL was stronger than their covariations with RF. However, covariation between VM and VL was also stronger than their covariations with VI. Since all vastii have identical actions on task variables, this finding suggests that covariation between muscle activity is not solely driven by simplification of overt task performance. Instead, the preferentially strong covariation between VM and VL is consistent with the control of internal joint stresses: Since VM and VL produce opposing mediolateral forces on the patella, the high positive correlation between their activation minimizes the net mediolateral patellar force. These results provide important insights into the interpretation of muscle covariations and their role in movement control.
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adaptation after vastus lateralis denervation in rats demonstrates Neural Regulation of joint stresses and strains
eLife, 2018Co-Authors: Cristiano Alessandro, Benjamin A Rellinger, Filipe O Barroso, Matthew C TreschAbstract:Although most of us will never achieve the grace and dexterity of professional ballerina Misty Copeland, we each make sophisticated, complex movements every day. Even simple movements often involve coordinating many muscles throughout the body. Moreover, because we have so many muscles, there are often multiple ways that we could use them to make the same movement. So which ones do we use, and why? Many studies into muscle control focus on how the muscles activate to perform a task like kicking a soccer ball. But muscles do more than just move the limbs; they also act on joints. Contracting a muscle exerts strain on bones and the ligaments that hold joints together. If these strains become excessive, they may cause pain and injury, and over a longer time may lead to arthritis. It would therefore make sense if the nervous system factored in the need to protect joints when turning on muscles. The quadriceps are a group of muscles that stretch along the front of the thigh bone and help to straighten the knee. To investigate whether the nervous system selects muscle activations to avoid joint injuries, Alessando et al. studied rats that had one particular quadriceps muscle paralyzed. The easiest way for the rats to adapt to this paralysis would be to increase the activation of a muscle that performs the same role as the paralyzed one, but places more stress on the knee joint. Instead, Alessando et al. found that the rats increase the activation of a muscle that minimizes the stress placed on the knee, even though this made it more difficult for the rats to recover their ability to use the leg in certain tasks. The results presented by Alessando et al. may have important implications for physical therapy. Clinicians usually work to restore limb movements so that a task is performed in a way that is similar to how it was done before the injury. But sometimes repairing the damage can change the mechanical properties of the joint – for example, reconstructive surgery may replace a damaged ligament with a graft that has a different strength or stiffness. In those cases, performing movements in the same way as before the surgery could place abnormal stress on the joint. However, much more research is needed before recommendations can be made for how to rehabilitate rats after injury, let alone humans.
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adaptation after vastus lateralis denervation in rats suggests Neural Regulation of joint stresses and strains
bioRxiv, 2018Co-Authors: Cristiano Alessandro, Benjamin A Rellinger, Filipe O Barroso, Matthew C TreschAbstract: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 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.
Kenton M Sanders - One of the best experts on this subject based on the ideXlab platform.
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platelet derived growth factor receptor α positive cells and not smooth muscle cells mediate purinergic hyperpolarization in murine colonic muscles
American Journal of Physiology-cell Physiology, 2014Co-Authors: Masaaki Kurahashi, Violeta N Mutafovayambolieva, Sang Don Koh, Kenton M SandersAbstract:Enteric inhibitory neurotransmission is an important feature of the Neural Regulation of gastrointestinal motility. Purinergic neurotransmission, via P2Y1 receptors, mediates one phase of inhibitor...
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regional variation in icc distribution pacemaking activity and Neural responses in the longitudinal muscle of the murine stomach
The Journal of Physiology, 2005Co-Authors: Guizhi Song, Kenton M Sanders, G David, S Hirst, Sean M WardAbstract:Intramuscular interstitial cells of Cajal (ICC-IM) play a critical role in enteric Neural Regulation of the circular muscle layer in the stomach, but no studies have been performed on the longitudinal layer. Kit immunohistochemistry was used to examine ICC-IM in the longitudinal muscle layer of the murine corpus and antrum, and it revealed marked heterogeneity in the distribution of ICC-IM in longitudinal muscles. In the corpus, ICC-IM were found along the greater curvature near the fundus. ICC-IM decreased in density in the circumferential axis toward the lesser curvature and in the longitudinal axis toward the antrum. ICC-IM were absent from the longitudinal layer of the antrum. Double labelling with markers for specific classes of enteric motor neurones revealed that cholinergic and nitrergic motor neurones formed close contacts with ICC-IM in the corpus but not in the antrum. Enteric nerve stimulation evoked prominent cholinergic excitatory and nitrergic inhibitory responses in longitudinal muscles of the corpus, but not in the antrum of wild-type animals. Cholinergic and nitrergic nerves were also present in W/WV mice, but functional innervation of the longitudinal muscle layer by these nerves in the corpus and antrum were absent. The data show that cholinergic and nitrergic neurotransmission only occurs in the gastric longitudinal layer in regions where ICC-IM are present. In regions, such as the corpus, where ICC-IM are common, robust Neural responses are present, but the reduced density of ICC-IM near the lesser curvature and in the distal stomach leads to reduced Neural Regulation in these gastric regions.
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iv Neural Regulation of gastrointestinal smooth muscle
American Journal of Physiology-gastrointestinal and Liver Physiology, 1998Co-Authors: Kenton M SandersAbstract:G protein-coupled receptors receive many of the Neural, hormonal, and paracrine inputs to gastrointestinal (GI) smooth muscle cells. This article examines the major G protein-coupled receptors, G p...
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enteric inhibitory Neural Regulation of human colonic circular muscle role of nitric oxide
Gastroenterology, 1993Co-Authors: K D Keef, Sean M Ward, Byron Mcgregor, Kenton M SandersAbstract:Abstract Background: Nitric oxide and an apamin-sensitive transmitter may both contribute to Neural inhibition in the human colon. The present study investigated the role of NO in regulating spontaneous rhythmic contractions and examined NO-dependent and independent components of Neurally evoked hyperpolarization in the human colon. Methods: Mechanical and electrical activity were recorded from isolated circular muscle strips. Results: Rhythmic contractions were inhibited by nerve stimulation. This response was reduced by apamin, oxyhemoglobin, and l- N G -nitro arginine methyl ester (l-NAME). Electrical recording revealed two components of Neurally evoked hyperpolarization: a fast hyperpolarization resulting from a single stimulus and a sustained hyperpolarization that developed with repetitive stimulation. Fast hyperpolarization was not affected by l-NAME or oxyhemoglobin but was significantly reduced by apamin. The sustained hyperpolarization was reduced by l-NAME or apamin. Exogenous NO and the P 2y receptor agonist 2-methylthio adenosine 5′-triphosphate (2-MATP) inhibited spontaneous contractions and produced hyperpolarization. Apamin reduced the effects of 2-MATP but not those of NO. Conclusions: The results support the concept that the inhibitory neurotransmission in the human colon involves two transmitters. A single stimulus results in an apamin-sensitive response. With multiple stimuli, a NO-dependent response develops and sums with the apamin-sensitive mechanism, producing sustained hyperpolarization and inhibition of contractions.
Cristiano Alessandro - One of the best experts on this subject based on the ideXlab platform.
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coordination amongst quadriceps muscles suggests Neural Regulation of internal joint stresses not simplification of task performance
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Cristiano Alessandro, Filipe O Barroso, Matthew C Tresch, Adarsh Prashara, David P Tentler, Hsin Yun YehAbstract:Many studies have demonstrated covariation between muscle activations during behavior, suggesting that muscles are not controlled independently. According to one common proposal, this covariation reflects simplification of task performance by the nervous system so that muscles with similar contributions to task variables are controlled together. Alternatively, this covariation might reflect Regulation of low-level aspects of movements that are common across tasks, such as stresses within joints. We examined these issues by analyzing covariation patterns in quadriceps muscle activity during locomotion in rats. The three monoarticular quadriceps muscles (vastus medialis [VM], vastus lateralis [VL], and vastus intermedius [VI]) produce knee extension and so have identical contributions to task performance; the biarticular rectus femoris (RF) produces an additional hip flexion. Consistent with the proposal that muscle covariation is related to similarity of muscle actions on task variables, we found that the covariation between VM and VL was stronger than their covariations with RF. However, covariation between VM and VL was also stronger than their covariations with VI. Since all vastii have identical actions on task variables, this finding suggests that covariation between muscle activity is not solely driven by simplification of overt task performance. Instead, the preferentially strong covariation between VM and VL is consistent with the control of internal joint stresses: Since VM and VL produce opposing mediolateral forces on the patella, the high positive correlation between their activation minimizes the net mediolateral patellar force. These results provide important insights into the interpretation of muscle covariations and their role in movement control.
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adaptation after vastus lateralis denervation in rats demonstrates Neural Regulation of joint stresses and strains
eLife, 2018Co-Authors: Cristiano Alessandro, Benjamin A Rellinger, Filipe O Barroso, Matthew C TreschAbstract:Although most of us will never achieve the grace and dexterity of professional ballerina Misty Copeland, we each make sophisticated, complex movements every day. Even simple movements often involve coordinating many muscles throughout the body. Moreover, because we have so many muscles, there are often multiple ways that we could use them to make the same movement. So which ones do we use, and why? Many studies into muscle control focus on how the muscles activate to perform a task like kicking a soccer ball. But muscles do more than just move the limbs; they also act on joints. Contracting a muscle exerts strain on bones and the ligaments that hold joints together. If these strains become excessive, they may cause pain and injury, and over a longer time may lead to arthritis. It would therefore make sense if the nervous system factored in the need to protect joints when turning on muscles. The quadriceps are a group of muscles that stretch along the front of the thigh bone and help to straighten the knee. To investigate whether the nervous system selects muscle activations to avoid joint injuries, Alessando et al. studied rats that had one particular quadriceps muscle paralyzed. The easiest way for the rats to adapt to this paralysis would be to increase the activation of a muscle that performs the same role as the paralyzed one, but places more stress on the knee joint. Instead, Alessando et al. found that the rats increase the activation of a muscle that minimizes the stress placed on the knee, even though this made it more difficult for the rats to recover their ability to use the leg in certain tasks. The results presented by Alessando et al. may have important implications for physical therapy. Clinicians usually work to restore limb movements so that a task is performed in a way that is similar to how it was done before the injury. But sometimes repairing the damage can change the mechanical properties of the joint – for example, reconstructive surgery may replace a damaged ligament with a graft that has a different strength or stiffness. In those cases, performing movements in the same way as before the surgery could place abnormal stress on the joint. However, much more research is needed before recommendations can be made for how to rehabilitate rats after injury, let alone humans.
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adaptation after vastus lateralis denervation in rats suggests Neural Regulation of joint stresses and strains
bioRxiv, 2018Co-Authors: Cristiano Alessandro, Benjamin A Rellinger, Filipe O Barroso, Matthew C TreschAbstract: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 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.
Filipe O Barroso - One of the best experts on this subject based on the ideXlab platform.
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coordination amongst quadriceps muscles suggests Neural Regulation of internal joint stresses not simplification of task performance
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Cristiano Alessandro, Filipe O Barroso, Matthew C Tresch, Adarsh Prashara, David P Tentler, Hsin Yun YehAbstract:Many studies have demonstrated covariation between muscle activations during behavior, suggesting that muscles are not controlled independently. According to one common proposal, this covariation reflects simplification of task performance by the nervous system so that muscles with similar contributions to task variables are controlled together. Alternatively, this covariation might reflect Regulation of low-level aspects of movements that are common across tasks, such as stresses within joints. We examined these issues by analyzing covariation patterns in quadriceps muscle activity during locomotion in rats. The three monoarticular quadriceps muscles (vastus medialis [VM], vastus lateralis [VL], and vastus intermedius [VI]) produce knee extension and so have identical contributions to task performance; the biarticular rectus femoris (RF) produces an additional hip flexion. Consistent with the proposal that muscle covariation is related to similarity of muscle actions on task variables, we found that the covariation between VM and VL was stronger than their covariations with RF. However, covariation between VM and VL was also stronger than their covariations with VI. Since all vastii have identical actions on task variables, this finding suggests that covariation between muscle activity is not solely driven by simplification of overt task performance. Instead, the preferentially strong covariation between VM and VL is consistent with the control of internal joint stresses: Since VM and VL produce opposing mediolateral forces on the patella, the high positive correlation between their activation minimizes the net mediolateral patellar force. These results provide important insights into the interpretation of muscle covariations and their role in movement control.
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adaptation after vastus lateralis denervation in rats demonstrates Neural Regulation of joint stresses and strains
eLife, 2018Co-Authors: Cristiano Alessandro, Benjamin A Rellinger, Filipe O Barroso, Matthew C TreschAbstract:Although most of us will never achieve the grace and dexterity of professional ballerina Misty Copeland, we each make sophisticated, complex movements every day. Even simple movements often involve coordinating many muscles throughout the body. Moreover, because we have so many muscles, there are often multiple ways that we could use them to make the same movement. So which ones do we use, and why? Many studies into muscle control focus on how the muscles activate to perform a task like kicking a soccer ball. But muscles do more than just move the limbs; they also act on joints. Contracting a muscle exerts strain on bones and the ligaments that hold joints together. If these strains become excessive, they may cause pain and injury, and over a longer time may lead to arthritis. It would therefore make sense if the nervous system factored in the need to protect joints when turning on muscles. The quadriceps are a group of muscles that stretch along the front of the thigh bone and help to straighten the knee. To investigate whether the nervous system selects muscle activations to avoid joint injuries, Alessando et al. studied rats that had one particular quadriceps muscle paralyzed. The easiest way for the rats to adapt to this paralysis would be to increase the activation of a muscle that performs the same role as the paralyzed one, but places more stress on the knee joint. Instead, Alessando et al. found that the rats increase the activation of a muscle that minimizes the stress placed on the knee, even though this made it more difficult for the rats to recover their ability to use the leg in certain tasks. The results presented by Alessando et al. may have important implications for physical therapy. Clinicians usually work to restore limb movements so that a task is performed in a way that is similar to how it was done before the injury. But sometimes repairing the damage can change the mechanical properties of the joint – for example, reconstructive surgery may replace a damaged ligament with a graft that has a different strength or stiffness. In those cases, performing movements in the same way as before the surgery could place abnormal stress on the joint. However, much more research is needed before recommendations can be made for how to rehabilitate rats after injury, let alone humans.
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adaptation after vastus lateralis denervation in rats suggests Neural Regulation of joint stresses and strains
bioRxiv, 2018Co-Authors: Cristiano Alessandro, Benjamin A Rellinger, Filipe O Barroso, Matthew C TreschAbstract: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 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.
Esther M Sternberg - One of the best experts on this subject based on the ideXlab platform.
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Neural Regulation of innate immunity a coordinated nonspecific host response to pathogens
Nature Reviews Immunology, 2006Co-Authors: Esther M SternbergAbstract:The central nervous system (CNS) regulates innate immune responses through hormonal and neuronal routes. The neuroendocrine stress response and the sympathetic and parasympathetic nervous systems generally inhibit innate immune responses at systemic and regional levels, whereas the peripheral nervous system tends to amplify local innate immune responses. These systems work together to first activate and amplify local inflammatory responses that contain or eliminate invading pathogens, and subsequently to terminate inflammation and restore host homeostasis. Here, I review these regulatory mechanisms and discuss the evidence indicating that the CNS can be considered as integral to acute-phase inflammatory responses to pathogens as the innate immune system.