The Experts below are selected from a list of 13716 Experts worldwide ranked by ideXlab platform
Karl Deisseroth - One of the best experts on this subject based on the ideXlab platform.
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Modular Organization of the brainstem noradrenaline system coordinates opposing learning states
Nature Neuroscience, 2017Co-Authors: Akira Uematsu, Edga A Ycu, Jessica Sulkes Cuevas, Jenny Koivumaa, Feli Junye, Eric J Kreme, Ilana Witte, Karl DeisserothAbstract:A small population of brainstem noradrenaline neurons powerfully modulates global brain function, but how they regulate diverse—and at times opposing—functions is not clear. The authors report that a Modular Organization in this neuromodulatory system, coupled with context-dependent activation modes, controls the balance between opposing emotional and flexible learning states.
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Modular Organization of the brainstem noradrenaline system coordinates opposing learning states
Nature Neuroscience, 2017Co-Authors: Akira Uematsu, Edga A Ycu, Jessica Sulkes Cuevas, Jenny Koivumaa, Bao Zhen Tan, Felix Junyent, Eric J Kremer, Ilana B Witten, Karl DeisserothAbstract:Noradrenaline modulates global brain states and diverse behaviors through what is traditionally believed to be a homogeneous cell population in the brainstem locus coeruleus (LC). However, it is unclear how LC coordinates disparate behavioral functions. We report a Modular LC Organization in rats, endowed with distinct neural projection patterns and coding properties for flexible specification of opposing behavioral learning states. LC projection mapping revealed functionally distinct cell modules with specific anatomical connectivity. An amygdala-projecting ensemble promoted aversive learning, while an independent medial prefrontal cortex-projecting ensemble extinguished aversive responses to enable flexible behavior. LC neurons displayed context-dependent inter-relationships, with moderate, discrete activation of distinct cell populations by fear or safety cues and robust, global recruitment of most cells by strong aversive stimuli. These results demonstrate a Modular Organization in LC in which combinatorial activation modes are coordinated with projection- and behavior-specific cell populations, enabling adaptive tuning of emotional responding and behavioral flexibility.
Nazar Mashtalir - One of the best experts on this subject based on the ideXlab platform.
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Modular Organization and assembly of swi snf family chromatin remodeling complexes
Cell, 2018Co-Authors: Nazar Mashtalir, Brittany C. Michel, Jie Luo, Joshua Pan, Andrew R Davino, Jordan OttoAbstract:Mammalian SWI/SNF (mSWI/SNF) ATP-dependent chromatin remodeling complexes are multi-subunit molecular machines that play vital roles in regulating genomic architecture and are frequently disrupted in human cancer and developmental disorders. To date, the Modular Organization and pathways of assembly of these chromatin regulators remain unknown, presenting a major barrier to structural and functional determination. Here, we elucidate the architecture and assembly pathway across three classes of mSWI/SNF complexes—canonical BRG1/BRM-associated factor (BAF), polybromo-associated BAF (PBAF), and newly defined ncBAF complexes—and define the requirement of each subunit for complex formation and stability. Using affinity purification of endogenous complexes from mammalian and Drosophila cells coupled with cross-linking mass spectrometry (CX-MS) and mutagenesis, we uncover three distinct and evolutionarily conserved modules, their Organization, and the temporal incorporation of these modules into each complete mSWI/SNF complex class. Finally, we map human disease-associated mutations within subunits and modules, defining specific topological regions that are affected upon subunit perturbation.
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Modular Organization and Assembly of SWI/SNF Family Chromatin Remodeling Complexes
Cell, 2018Co-Authors: Nazar Mashtalir, Andrew R. D’avino, Brittany C. Michel, Jie Luo, Joshua Pan, Jordan E. Otto, Hayley J. Zullow, Zachary M. Mckenzie, Rachel L. Kubiak, Roodolph St. PierreAbstract:Mammalian SWI/SNF (mSWI/SNF) ATP-dependent chromatin remodeling complexes are multi-subunit molecular machines that play vital roles in regulating genomic architecture and are frequently disrupted in human cancer and developmental disorders. To date, the Modular Organization and pathways of assembly of these chromatin regulators remain unknown, presenting a major barrier to structural and functional determination. Here, we elucidate the architecture and assembly pathway across three classes of mSWI/SNF complexes—canonical BRG1/BRM-associated factor (BAF), polybromo-associated BAF (PBAF), and newly defined ncBAF complexes—and define the requirement of each subunit for complex formation and stability. Using affinity purification of endogenous complexes from mammalian and Drosophila cells coupled with cross-linking mass spectrometry (CX-MS) and mutagenesis, we uncover three distinct and evolutionarily conserved modules, their Organization, and the temporal incorporation of these modules into each complete mSWI/SNF complex class. Finally, we map human disease-associated mutations within subunits and modules, defining specific topological regions that are affected upon subunit perturbation.
Jessica Sulkes Cuevas - One of the best experts on this subject based on the ideXlab platform.
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Modular Organization of the brainstem noradrenaline system coordinates opposing learning states
Nature Neuroscience, 2017Co-Authors: Akira Uematsu, Edga A Ycu, Jessica Sulkes Cuevas, Jenny Koivumaa, Feli Junye, Eric J Kreme, Ilana Witte, Karl DeisserothAbstract:A small population of brainstem noradrenaline neurons powerfully modulates global brain function, but how they regulate diverse—and at times opposing—functions is not clear. The authors report that a Modular Organization in this neuromodulatory system, coupled with context-dependent activation modes, controls the balance between opposing emotional and flexible learning states.
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Modular Organization of the brainstem noradrenaline system coordinates opposing learning states
Nature Neuroscience, 2017Co-Authors: Akira Uematsu, Edga A Ycu, Jessica Sulkes Cuevas, Jenny Koivumaa, Bao Zhen Tan, Felix Junyent, Eric J Kremer, Ilana B Witten, Karl DeisserothAbstract:Noradrenaline modulates global brain states and diverse behaviors through what is traditionally believed to be a homogeneous cell population in the brainstem locus coeruleus (LC). However, it is unclear how LC coordinates disparate behavioral functions. We report a Modular LC Organization in rats, endowed with distinct neural projection patterns and coding properties for flexible specification of opposing behavioral learning states. LC projection mapping revealed functionally distinct cell modules with specific anatomical connectivity. An amygdala-projecting ensemble promoted aversive learning, while an independent medial prefrontal cortex-projecting ensemble extinguished aversive responses to enable flexible behavior. LC neurons displayed context-dependent inter-relationships, with moderate, discrete activation of distinct cell populations by fear or safety cues and robust, global recruitment of most cells by strong aversive stimuli. These results demonstrate a Modular Organization in LC in which combinatorial activation modes are coordinated with projection- and behavior-specific cell populations, enabling adaptive tuning of emotional responding and behavioral flexibility.
Linyuan Lu - One of the best experts on this subject based on the ideXlab platform.
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individual t1 weighted t2 weighted ratio brain networks small worldness hubs and Modular Organization
International Journal of Modern Physics C, 2018Co-Authors: Huijun Wu, Hao Wang, Linyuan LuAbstract:Applying network science to investigate the complex systems has become a hot topic. In neuroscience, understanding the architectures of complex brain networks was a vital issue. An enormous amount of evidence had supported the brain was cost/efficiency trade-off with small-worldness, hubness and Modular Organization through the functional MRI and structural MRI investigations. However, the T1-weighted/T2-weighted (T1w/T2w) ratio brain networks were mostly unexplored. Here, we utilized a KL divergence-based method to construct large-scale individual T1w/T2w ratio brain networks and investigated the underlying topological attributes of these networks. Our results supported that the T1w/T2w ratio brain networks were comprised of small-worldness, an exponentially truncated power–law degree distribution, frontal-parietal hubs and Modular Organization. Besides, there were significant positive correlations between the network metrics and fluid intelligence. Thus, the T1w/T2w ratio brain networks open a new avenue to understand the human brain and are a necessary supplement for future MRI studies.
Adamantios Arampatzis - One of the best experts on this subject based on the ideXlab platform.
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Modular Organization of murine locomotor pattern in the presence and absence of sensory feedback from muscle spindles.
The Journal of physiology, 2019Co-Authors: Alessandro Santuz, Turgay Akay, William Paganini Mayer, Tyler L. Wells, Arno Schroll, Adamantios ArampatzisAbstract:KEY POINTS Locomotion on land and in water requires the coordination of a great number of muscle activations and joint movements. Constant feedback about the position of own body parts in relation to the surrounding environment and the body itself (proprioception) is required to maintain stability and avoid failure. The central nervous system may follow a Modular type of Organization by controlling muscles in orchestrated groups (muscle synergies) rather than individually. We used this concept on genetically modified mice lacking muscle spindles, one of the two main classes of proprioceptors. We provide evidence that proprioceptive feedback is required by the central nervous system to accurately tune the Modular Organization of locomotion. ABSTRACT For exploiting terrestrial and aquatic locomotion, vertebrates must build their locomotor patterns based on an enormous amount of variables. The great number of muscles and joints, together with the constant need for sensory feedback information (e.g. proprioception), make the task of controlling movement a problem with overabundant degrees of freedom. It is widely accepted that the central nervous system may simplify the creation and control of movement by generating activation patterns common to muscle groups, rather than specific to individual muscles. These activation patterns, called muscle synergies, describe the Modular Organization of movement. We extracted synergies through electromyography from the hind limb muscle activities of wild-type and genetically modified mice lacking sensory feedback from muscle spindles. Muscle spindle-deficient mice underwent a modification of the temporal structure (motor primitives) of muscle synergies that resulted in diminished functionality during walking. In addition, both the temporal and spatial (motor modules) components of synergies were severely affected when external perturbations were introduced or when animals were immersed in water. These findings show that sensory feedback from group Ia/II muscle spindles regulates motor function in normal and perturbed walking. Moreover, when group Ib Golgi tendon organ feedback is lacking due to enhanced buoyancy, the Modular Organization of swimming is almost completely compromised.
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Modular Organization of the murine locomotor pattern in presence and absence of sensory feedback from muscle spindles
2018Co-Authors: Alessandro Santuz, Turgay Akay, William Paganini Mayer, Tyler L. Wells, Arno Schroll, Adamantios ArampatzisAbstract:For exploiting terrestrial and aquatic locomotion, vertebrates must build their locomotor patterns based on an enormous amount of variables. The great number of muscles and joints, together with the constant need for sensory feedback information (e.g. proprioception), make the task of creating and controlling movement a problem with overabundant degrees of freedom. It is widely accepted that the central nervous system might simplify the creation and control of movement. This could happen through the generation of activation patterns, which are common to many different muscles, rather than specific to individual muscles. These activation patterns, called muscle synergies, can be extracted from electromyographic data and describe the Modular Organization of movement. We extracted muscle synergies from the hindlimb muscle activities of wild type and genetically modified mice, in which sensory feedback from muscle spindles is eliminated. Muscle spindle-deficient mice underwent a modification of the temporal structure (motor primitives) of muscle synergies that resulted in diminished functionality during walking. In addition, both the temporal and spatial components (motor modules) of muscle synergies were severely affected when external perturbations were introduced of when animals were immersed in water. These findings show that group Ia/II sensory feedback from muscle spindles regulates motor function in normal and perturbed walking. Moreover, when group Ib Golgi tendon organ feedback is lacking due to the reduction of gravitational load in conditions of enhanced buoyancy, the Modular Organization of swimming is almost completely compromised.
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The Influence of Footwear on the Modular Organization of Running
Frontiers in physiology, 2017Co-Authors: Alessandro Santuz, Antonis Ekizos, Lars Janshen, Vasilios Baltzopoulos, Adamantios ArampatzisAbstract:For most of our history, we predominantly ran barefoot or in minimalist shoes. The advent of modern footwear, however, might have introduced alterations in the motor control of running. The present study investigated shod and barefoot running under the perspective of the Modular Organization of muscle activation, in order to help addressing the neurophysiological factors underlying human locomotion. On a treadmill, 20 young and healthy inexperienced barefoot runners ran shod and barefoot at preferred speed (2.8 ± 0.4 m/s). Fundamental synergies, containing the time-dependent activation coefficients (motor primitives) and the time-invariant muscle weightings (motor modules), were extracted from 24 ipsilateral electromyographic activities using non-negative matrix factorization. In shod running, the average foot strike pattern was a rearfoot strike, while in barefoot running it was a mid-forefoot strike. In both conditions, five fundamental synergies were enough to describe as many gait cycle phases: weight acceptance, propulsion, arm swing, early swing and late swing. We found the motor primitives to be generally shifted earlier in time during the stance-related phases and later in the swing-related ones in barefoot running. The motor primitive describing the propulsion phase was significantly of shorter duration (peculiarity confirmed by the analysis of the spinal motor output). The arm swing primitive, instead, was significantly wider in the barefoot condition. The motor modules demonstrated analogous Organization with some significant differences in the propulsion, arm swing and late swing synergies. Other than to the trivial absence of shoes, the differences might be deputed to the lower ankle gear ratio (and the consequent increased system instability) and to the higher recoil capabilities of the longitudinal foot arch during barefoot compared to shod running. © 2017 Santuz, Ekizos, Janshen, Baltzopoulos and Arampatzis.