The Experts below are selected from a list of 32085 Experts worldwide ranked by ideXlab platform
Réjean Dubuc - One of the best experts on this subject based on the ideXlab platform.
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A Brainstem Neural Substrate for Stopping Locomotion.
The Journal of Neuroscience, 2018Co-Authors: Swantje Grätsch, François Auclair, Olivier Demers, Emmanuella Auguste, Amer Hanna, Ansgar Büschges, Réjean DubucAbstract:Locomotion occurs sporadically and needs to be started, maintained, and stopped. The Neural Substrate underlying the activation of locomotion is partly known, but little is known about mechanisms involved in termination of locomotion. Recently, reticulospinal neurons (stop cells) were found to play a crucial role in stopping locomotion in the lamprey: their activation halts ongoing locomotion and their inactivation slows down the termination process. Intracellular recordings of these cells revealed a distinct activity pattern, with a burst of action potentials at the beginning of a locomotor bout and one at the end (termination burst). The termination burst was shown to be time linked to the end of locomotion, but the mechanisms by which it is triggered have remained unknown. We studied this in larval sea lampreys (Petromyzon marinus; the sex of the animals was not taken into account). We found that the mesencephalic locomotor region (MLR), which is known to initiate and control locomotion, stops ongoing locomotion by providing synaptic inputs that trigger the termination burst in stop cells. When locomotion is elicited by MLR stimulation, a second MLR stimulation stops the locomotor bout if it is of lower intensity than the initial stimulation. This occurs for MLR-induced, sensory-evoked, and spontaneous locomotion. Furthermore, we show that glutamatergic and, most likely, monosynaptic projections from the MLR activate stop cells during locomotion. Therefore, activation of the MLR not only initiates locomotion, but can also control the end of a locomotor bout. These results provide new insights onto the Neural mechanisms responsible for stopping locomotion. SIGNIFICANCE STATEMENT The mesencephalic locomotor region (MLR) is a brainstem region well known to initiate and control locomotion. Since its discovery in cats in the 1960s, the MLR has been identified in all vertebrate species tested from lampreys to humans. We now demonstrate that stimulation of the MLR not only activates locomotion, but can also stop it. This is achieved through a descending glutamatergic signal, most likely monosynaptic, from the MLR to the reticular formation that activates reticulospinal stop cells. Together, our findings have uncovered a Neural mechanism for stopping locomotion and bring new insights into the function of the MLR.
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A Brainstem Neural Substrate for Stopping Locomotion.
The Journal of Neuroscience, 2018Co-Authors: Swantje Grätsch, François Auclair, Olivier Demers, Emmanuella Auguste, Amer Hanna, Ansgar Büschges, Réjean DubucAbstract:Locomotion occurs sporadically and needs to be started, maintained, and stopped. The Neural Substrate underlying the activation of locomotion is partly known, but little is known about mechanisms involved in termination of locomotion. Recently, reticulospinal neurons (stop cells) were found to play a crucial role in stopping locomotion in the lamprey: their activation halts ongoing locomotion and their inactivation slows down the termination process. Intracellular recordings of these cells revealed a distinct activity pattern, with a burst of action potentials at the beginning of a locomotor bout and one at the end (termination burst). The termination burst was shown to be time linked to the end of locomotion, but the mechanisms by which it is triggered have remained unknown. We studied this in larval sea lampreys (Petromyzon marinus; the sex of the animals was not taken into account). We found that the mesencephalic locomotor region (MLR), which is known to initiate and control locomotion, stops ongoing locomotion by providing synaptic inputs that trigger the termination burst in stop cells. When locomotion is elicited by MLR stimulation, a second MLR stimulation stops the locomotor bout if it is of lower intensity than the initial stimulation. This occurs for MLR-induced, sensory-evoked, and spontaneous locomotion. Furthermore, we show that glutamatergic and, most likely, monosynaptic projections from the MLR activate stop cells during locomotion. Therefore, activation of the MLR not only initiates locomotion, but can also control the end of a locomotor bout. These results provide new insights onto the Neural mechanisms responsible for stopping locomotion. SIGNIFICANCE STATEMENT The mesencephalic locomotor region (MLR) is a brainstem region well known to initiate and control locomotion. Since its discovery in cats in the 1960s, the MLR has been identified in all vertebrate species tested from lampreys to humans. We now demonstrate that stimulation of the MLR not only activates locomotion, but can also stop it. This is achieved through a descending glutamatergic signal, most likely monosynaptic, from the MLR to the reticular formation that activates reticulospinal stop cells. Together, our findings have uncovered a Neural mechanism for stopping locomotion and bring new insights into the function of the MLR.
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Specific Neural Substrate linking respiration to locomotion
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Jean-françois Gariépy, François Auclair, Kianoush Missaghi, Stéphanie Chevallier, Shannon Chartré, Maxime Robert, James P. Lund, Réjean DubucAbstract:When animals move, respiration increases to adapt for increased energy demands; the underlying mechanisms are still not understood. We investigated the Neural Substrates underlying the respiratory changes in relation to movement in lampreys. We showed that respiration increases following stimulation of the mesencephalic locomotor region (MLR) in an in vitro isolated preparation, an effect that persists in the absence of the spinal cord and caudal brainstem. By using electrophysiological and anatomical techniques, including whole-cell patch recordings, we identified a subset of neurons located in the dorsal MLR that send direct inputs to neurons in the respiratory generator. In semi-intact preparations, blockade of this region with 6-cyano-7-nitroquinoxaline-2,3-dione and (2R)-amino-5-phosphonovaleric acid greatly reduced the respiratory increases without affecting the locomotor movements. These results show that neurons in the respiratory generator receive direct glutamatergic connections from the MLR and that a subpopulation of MLR neurons plays a key role in the respiratory changes linked to movement.
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a novel Neural Substrate for the transformation of olfactory inputs into motor output
PLOS Biology, 2010Co-Authors: François Auclair, Dominique Derjean, Aimen Moussaddy, Elias Atallah, Melissa Stpierre, Steven Chang, Xiang Ren, Barbara S Zielinski, Réjean DubucAbstract:It is widely recognized that animals respond to odors by generating or modulating specific motor behaviors. These reactions are important for daily activities, reproduction, and survival. In the sea lamprey, mating occurs after ovulated females are attracted to spawning sites by male sex pheromones. The ubiquity and reliability of olfactory-motor behavioral responses in vertebrates suggest tight coupling between the olfactory system and brain areas controlling movements. However, the circuitry and the underlying cellular Neural mechanisms remain largely unknown. Using lamprey brain preparations, and electrophysiology, calcium imaging, and tract tracing experiments, we describe the Neural Substrate responsible for transforming an olfactory input into a locomotor output. We found that olfactory stimulation with naturally occurring odors and pheromones induced large excitatory responses in reticulospinal cells, the command neurons for locomotion. We have also identified the anatomy and physiology of this circuit. The olfactory input was relayed in the medial part of the olfactory bulb, in the posterior tuberculum, in the mesencephalic locomotor region, to finally reach reticulospinal cells in the hindbrain. Activation of this olfactory-motor pathway generated rhythmic ventral root discharges and swimming movements. Our study bridges the gap between behavior and cellular Neural mechanisms in vertebrates, identifying a specific subsystem within the CNS, dedicated to producing motor responses to olfactory inputs.
Christophe Lançon - One of the best experts on this subject based on the ideXlab platform.
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Corrigendum: Neural Substrate of quality of life in patients with schizophrenia: a magnetisation transfer imaging study
Scientific reports, 2016Co-Authors: Catherine Faget-agius, Laurent Boyer, Jonathan Wirsich, Jean-philippe Ranjeva, Raphaëlle Richieri, Elisabeth Soulier, Sylviane Confort-gouny, Pascal Auquier, Maxime Guye, Christophe LançonAbstract:Corrigendum: Neural Substrate of quality of life in patients with schizophrenia: a magnetisation transfer imaging study
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Neural Substrate of quality of life in patients with schizophrenia: a magnetisation transfer imaging study
Scientific Reports, 2015Co-Authors: Catherine Faget-agius, Laurent Boyer, Jonathan Wirsich, Raphaëlle Richieri, Elisabeth Soulier, Sylviane Confort-gouny, Pascal Auquier, Maxime Guye, Ranjeva Jean-philippe, Christophe LançonAbstract:The aim of this study was to investigate the Neural Substrate underlying quality of life (QoL) and to demonstrate the microstructural abnormalities associated with impaired QoL in a large sample of patients with schizophrenia, using magnetisation transfer imaging. A total of 81 right-handed men with a diagnosis of schizophrenia and 25 age- and sex-similar healthy controls were included and underwent a 3T MRI with magnetization transfer ratio (MTR) to detect microstructural abnormalities. Compared with healthy controls, patients with schizophrenia had grey matter (GM) decreased MTR values in the temporal lobe (BA21, BA37 and BA38), the bilateral insula, the occipital lobe (BA17, BA18 and BA19) and the cerebellum. Patients with impaired QoL had lower GM MTR values relative to patients with preserved QoL in the bilateral temporal pole (BA38), the bilateral insula, the secondary visual cortex (BA18), the vermis and the cerebellum. Significant correlations between MTR values and QoL scores (p \textless 0.005) were observed in the GM of patients in the right temporal pole (BA38), the bilateral insula, the vermis and the right cerebellum. Our study shows that QoL impairment in patients with schizophrenia is related to the microstructural changes in an extensive network, suggesting that QoL is a bio-psychosocial marker.
Rainer Goebel - One of the best experts on this subject based on the ideXlab platform.
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The Neural Substrate for working memory of tactile surface texture
Human brain mapping, 2012Co-Authors: Amanda L. Kaas, Hanneke I. Van Mier, Maya Visser, Rainer GoebelAbstract:Fine surface texture is best discriminated by touch, in contrast to macro geometric features like shape. We used functional magnetic resonance imaging and a delayed match-to-sample task to investigate the Neural Substrate for working memory of tactile surface texture. Blindfolded right-handed males encoded the texture or location of up to four sandpaper stimuli using the dominant or non-dominant hand. They maintained the information for 10-12 s and then answered whether a probe stimulus matched the memory array. Analyses of variance with the factors Hand, Task, and Load were performed on the estimated percent signal change for the encoding and delay phase. During encoding, contralateral effects of Hand were found in sensorimotor regions, whereas Load effects were observed in bilateral postcentral sulcus (BA2), secondary somatosensory cortex (S2), pre-SMA, dorsolateral prefrontal cortex (dlPFC), and superior parietal lobule (SPL). During encoding and delay, Task effects (texture > location) were found in central sulcus, S2, pre-SMA, dlPFC, and SPL. The Task and Load effects found in hand- and modality-specific regions BA2 and S2 indicate involvement of these regions in the tactile encoding and maintenance of fine surface textures. Similar effects in hand- and modality-unspecific areas dlPFC, pre-SMA and SPL suggest that these regions contribute to the cognitive monitoring required to encode and maintain multiple items. Our findings stress both the particular importance of S2 for the encoding and maintenance of tactile surface texture, as well as the supramodal nature of parieto-frontal networks involved in cognitive control. Hum Brain Mapp, 2012. (c) 2012 Wiley Periodicals, Inc.
Catherine Faget-agius - One of the best experts on this subject based on the ideXlab platform.
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Corrigendum: Neural Substrate of quality of life in patients with schizophrenia: a magnetisation transfer imaging study
Scientific reports, 2016Co-Authors: Catherine Faget-agius, Laurent Boyer, Jonathan Wirsich, Jean-philippe Ranjeva, Raphaëlle Richieri, Elisabeth Soulier, Sylviane Confort-gouny, Pascal Auquier, Maxime Guye, Christophe LançonAbstract:Corrigendum: Neural Substrate of quality of life in patients with schizophrenia: a magnetisation transfer imaging study
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Neural Substrate of quality of life in patients with schizophrenia: a magnetisation transfer imaging study
Scientific Reports, 2015Co-Authors: Catherine Faget-agius, Laurent Boyer, Jonathan Wirsich, Raphaëlle Richieri, Elisabeth Soulier, Sylviane Confort-gouny, Pascal Auquier, Maxime Guye, Ranjeva Jean-philippe, Christophe LançonAbstract:The aim of this study was to investigate the Neural Substrate underlying quality of life (QoL) and to demonstrate the microstructural abnormalities associated with impaired QoL in a large sample of patients with schizophrenia, using magnetisation transfer imaging. A total of 81 right-handed men with a diagnosis of schizophrenia and 25 age- and sex-similar healthy controls were included and underwent a 3T MRI with magnetization transfer ratio (MTR) to detect microstructural abnormalities. Compared with healthy controls, patients with schizophrenia had grey matter (GM) decreased MTR values in the temporal lobe (BA21, BA37 and BA38), the bilateral insula, the occipital lobe (BA17, BA18 and BA19) and the cerebellum. Patients with impaired QoL had lower GM MTR values relative to patients with preserved QoL in the bilateral temporal pole (BA38), the bilateral insula, the secondary visual cortex (BA18), the vermis and the cerebellum. Significant correlations between MTR values and QoL scores (p \textless 0.005) were observed in the GM of patients in the right temporal pole (BA38), the bilateral insula, the vermis and the right cerebellum. Our study shows that QoL impairment in patients with schizophrenia is related to the microstructural changes in an extensive network, suggesting that QoL is a bio-psychosocial marker.
Amanda L. Kaas - One of the best experts on this subject based on the ideXlab platform.
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The Neural Substrate for working memory of tactile surface texture
Human brain mapping, 2012Co-Authors: Amanda L. Kaas, Hanneke I. Van Mier, Maya Visser, Rainer GoebelAbstract:Fine surface texture is best discriminated by touch, in contrast to macro geometric features like shape. We used functional magnetic resonance imaging and a delayed match-to-sample task to investigate the Neural Substrate for working memory of tactile surface texture. Blindfolded right-handed males encoded the texture or location of up to four sandpaper stimuli using the dominant or non-dominant hand. They maintained the information for 10-12 s and then answered whether a probe stimulus matched the memory array. Analyses of variance with the factors Hand, Task, and Load were performed on the estimated percent signal change for the encoding and delay phase. During encoding, contralateral effects of Hand were found in sensorimotor regions, whereas Load effects were observed in bilateral postcentral sulcus (BA2), secondary somatosensory cortex (S2), pre-SMA, dorsolateral prefrontal cortex (dlPFC), and superior parietal lobule (SPL). During encoding and delay, Task effects (texture > location) were found in central sulcus, S2, pre-SMA, dlPFC, and SPL. The Task and Load effects found in hand- and modality-specific regions BA2 and S2 indicate involvement of these regions in the tactile encoding and maintenance of fine surface textures. Similar effects in hand- and modality-unspecific areas dlPFC, pre-SMA and SPL suggest that these regions contribute to the cognitive monitoring required to encode and maintain multiple items. Our findings stress both the particular importance of S2 for the encoding and maintenance of tactile surface texture, as well as the supramodal nature of parieto-frontal networks involved in cognitive control. Hum Brain Mapp, 2012. (c) 2012 Wiley Periodicals, Inc.