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Katsushige Sato - One of the best experts on this subject based on the ideXlab platform.
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developmental roles of the spontaneous Depolarization Wave in synaptic network formation in the embryonic brainstem
Neuroscience, 2017Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:Abstract One of the earliest activities expressed within the developing central nervous system is a widely propagating Wave-like activity, which we referred to as the Depolarization Wave. Despite considerable consensus concerning the global features of the activity, its physiological role is yet to be clarified. The Depolarization Wave is expressed during a specific period of functional synaptogenesis, and this developmental profile has led to the hypothesis that the Wave plays some roles in synaptic network organization. In the present study, we tested this hypothesis by inhibiting the Depolarization Wave in ovo and examining its effects on the development of functional synapses in vagus nerve-related brainstem nuclei of the chick embryo. Chronic inhibition of the Depolarization Wave had no significant effect on the developmental time course, amplitude, and spatial distribution of monosynaptic excitatory postsynaptic potentials in the first-order nuclei of the vagal sensory pathway (the nucleus of the tractus solitarius (NTS) and the contralateral non-NTS region), but reduced polysynaptic responses in the higher-order nucleus (the parabrachial nucleus). These results suggest that the Depolarization Wave plays an important role in the initial process of functional synaptic expression in the brainstem, especially in the higher-order nucleus of the cranial sensory pathway.
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maintenance of the large scale Depolarization Wave in the embryonic chick brain against deprivation of the rhythm generator
Neuroscience, 2014Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:Abstract Widely correlated spontaneous activity in the developing nervous system is transiently expressed and is considered to play a fundamental role in neural circuit formation. The Depolarization Wave, which spreads over a long distance along the neuraxis, maximally extending to the lumbosacral cord and forebrain, is an example of this spontaneous activity. Although the Depolarization Wave is typically initiated in the spinal cord in intact preparations, spontaneous discharges have also been detected in the isolated brainstem. Although this suggests that the brainstem has the ability to generate spontaneous activity, but is paced by a caudal rhythm generator of higher excitability, a number of questions remains. Does brainstem activity simply appear as a passive consequence, or does any active change occur in the brainstem network to compensate for this activity? If the latter is the case, does this compensation occur equally at different developmental stages? Where is the new rhythm generator in the isolated brainstem? To answer these questions, we optically analyzed spatio-temporal patterns of activity detected from the chick brainstem before and after transection at the obex. The results revealed that the Depolarization Wave was homeostatically maintained, which was characterized by an increase in excitability and/or the number of neurons recruited to the Wave. The Wave was more easily maintained in younger embryos. Furthermore, we demonstrated that the ability of brainstem neurons to perform such an active compensation was not lost even at the stage when the Depolarization Wave was no longer observed in the intact brainstem.
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optical imaging of the spontaneous Depolarization Wave in the mouse embryo origins and pharmacological nature
Annals of the New York Academy of Sciences, 2013Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we revealed previously in the chick and rat embryos that this correlated activity is a widely propagating Wave of neural Depolarization, which we termed the Depolarization Wave. One important consideration is whether a Depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the Depolarization Wave in the mouse embryo by summarizing spatiotemporal characteristics and pharmacological natures of the widely propagating Wave activity. The findings show that a synchronized Wave with common characteristics is expressed in different species, suggesting its fundamental roles in neural development.
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pharmacological mechanisms underlying switching from the large scale Depolarization Wave to segregated activity in the mouse central nervous system
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: During the early development of the nervous system, synchronized activity is observed in a variety of structures, and is considered to play a fundamental role in neural development. One of the most striking examples of such activity is the Depolarization Wave reported in chick and rat embryos. In the accompanying paper (Momose-Sato et al., 2012), we have demonstrated that a Depolarization Wave is also present in the mouse embryo by showing large-scale optical Waves, which spread remarkably over the central nervous system, including the spinal cord, hindbrain, cerebellum, midbrain, and forebrain. In the present study, we examined the pharmacological nature of the mouse Depolarization Wave and its developmental changes. We show here that two types of switching in pharmacological characteristics occur during development. One is that the Depolarization Wave is strongly dependent on nicotinic acetylcholine receptors during the early developmental stage [embryonic day (E)11-12], but is dominated by glutamate at the later stage (E13 onwards). The second is that γ-aminobutyric acid (GABA), which acts as an excitatory mediator of the Depolarization Wave during the early phase, becomes an inhibitory modulator by E14. These changes seemed to occur earlier in the hindbrain than in the spinal cord. Furthermore, we show that the second switch causes the loss of synchronization over the network, resulting in the disappearance of the Depolarization Wave and segregation of the activity into discrete regions of the medulla and spinal cord. We suggest that pharmacological switching is a possible mechanism underlying replacement of the primordial correlated network by a mature neuronal circuit.
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spontaneous Depolarization Wave in the mouse embryo origin and large scale propagation over the cns identified with voltage sensitive dye imaging
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we have revealed previously that this correlated activity is a widely propagating Wave of neural Depolarization, which we termed the Depolarization Wave. We have observed in the chick and rat embryos that the activity spread over an extensive region of the CNS, including the spinal cord, hindbrain, cerebellum, midbrain and forebrain. One important consideration is whether a Depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the Depolarization Wave in the mouse embryo by showing that the widely propagating Wave appeared independently of the localized spontaneous activity detected previously with Ca(2+) imaging. Furthermore, we mapped the origin of the Depolarization Wave and revealed that the Wave generator moved from the rostral spinal cord to the caudal cord as development proceeded, and was later replaced with mature rhythmogenerators. The present study, together with an accompanying paper that describes pharmacological properties of the mouse Depolarization Wave, shows that a synchronized Wave with common characteristics is expressed in different species, suggesting fundamental roles in neural development.
Yoko Momosesato - One of the best experts on this subject based on the ideXlab platform.
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developmental roles of the spontaneous Depolarization Wave in synaptic network formation in the embryonic brainstem
Neuroscience, 2017Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:Abstract One of the earliest activities expressed within the developing central nervous system is a widely propagating Wave-like activity, which we referred to as the Depolarization Wave. Despite considerable consensus concerning the global features of the activity, its physiological role is yet to be clarified. The Depolarization Wave is expressed during a specific period of functional synaptogenesis, and this developmental profile has led to the hypothesis that the Wave plays some roles in synaptic network organization. In the present study, we tested this hypothesis by inhibiting the Depolarization Wave in ovo and examining its effects on the development of functional synapses in vagus nerve-related brainstem nuclei of the chick embryo. Chronic inhibition of the Depolarization Wave had no significant effect on the developmental time course, amplitude, and spatial distribution of monosynaptic excitatory postsynaptic potentials in the first-order nuclei of the vagal sensory pathway (the nucleus of the tractus solitarius (NTS) and the contralateral non-NTS region), but reduced polysynaptic responses in the higher-order nucleus (the parabrachial nucleus). These results suggest that the Depolarization Wave plays an important role in the initial process of functional synaptic expression in the brainstem, especially in the higher-order nucleus of the cranial sensory pathway.
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maintenance of the large scale Depolarization Wave in the embryonic chick brain against deprivation of the rhythm generator
Neuroscience, 2014Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:Abstract Widely correlated spontaneous activity in the developing nervous system is transiently expressed and is considered to play a fundamental role in neural circuit formation. The Depolarization Wave, which spreads over a long distance along the neuraxis, maximally extending to the lumbosacral cord and forebrain, is an example of this spontaneous activity. Although the Depolarization Wave is typically initiated in the spinal cord in intact preparations, spontaneous discharges have also been detected in the isolated brainstem. Although this suggests that the brainstem has the ability to generate spontaneous activity, but is paced by a caudal rhythm generator of higher excitability, a number of questions remains. Does brainstem activity simply appear as a passive consequence, or does any active change occur in the brainstem network to compensate for this activity? If the latter is the case, does this compensation occur equally at different developmental stages? Where is the new rhythm generator in the isolated brainstem? To answer these questions, we optically analyzed spatio-temporal patterns of activity detected from the chick brainstem before and after transection at the obex. The results revealed that the Depolarization Wave was homeostatically maintained, which was characterized by an increase in excitability and/or the number of neurons recruited to the Wave. The Wave was more easily maintained in younger embryos. Furthermore, we demonstrated that the ability of brainstem neurons to perform such an active compensation was not lost even at the stage when the Depolarization Wave was no longer observed in the intact brainstem.
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optical imaging of the spontaneous Depolarization Wave in the mouse embryo origins and pharmacological nature
Annals of the New York Academy of Sciences, 2013Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we revealed previously in the chick and rat embryos that this correlated activity is a widely propagating Wave of neural Depolarization, which we termed the Depolarization Wave. One important consideration is whether a Depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the Depolarization Wave in the mouse embryo by summarizing spatiotemporal characteristics and pharmacological natures of the widely propagating Wave activity. The findings show that a synchronized Wave with common characteristics is expressed in different species, suggesting its fundamental roles in neural development.
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pharmacological mechanisms underlying switching from the large scale Depolarization Wave to segregated activity in the mouse central nervous system
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: During the early development of the nervous system, synchronized activity is observed in a variety of structures, and is considered to play a fundamental role in neural development. One of the most striking examples of such activity is the Depolarization Wave reported in chick and rat embryos. In the accompanying paper (Momose-Sato et al., 2012), we have demonstrated that a Depolarization Wave is also present in the mouse embryo by showing large-scale optical Waves, which spread remarkably over the central nervous system, including the spinal cord, hindbrain, cerebellum, midbrain, and forebrain. In the present study, we examined the pharmacological nature of the mouse Depolarization Wave and its developmental changes. We show here that two types of switching in pharmacological characteristics occur during development. One is that the Depolarization Wave is strongly dependent on nicotinic acetylcholine receptors during the early developmental stage [embryonic day (E)11-12], but is dominated by glutamate at the later stage (E13 onwards). The second is that γ-aminobutyric acid (GABA), which acts as an excitatory mediator of the Depolarization Wave during the early phase, becomes an inhibitory modulator by E14. These changes seemed to occur earlier in the hindbrain than in the spinal cord. Furthermore, we show that the second switch causes the loss of synchronization over the network, resulting in the disappearance of the Depolarization Wave and segregation of the activity into discrete regions of the medulla and spinal cord. We suggest that pharmacological switching is a possible mechanism underlying replacement of the primordial correlated network by a mature neuronal circuit.
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spontaneous Depolarization Wave in the mouse embryo origin and large scale propagation over the cns identified with voltage sensitive dye imaging
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we have revealed previously that this correlated activity is a widely propagating Wave of neural Depolarization, which we termed the Depolarization Wave. We have observed in the chick and rat embryos that the activity spread over an extensive region of the CNS, including the spinal cord, hindbrain, cerebellum, midbrain and forebrain. One important consideration is whether a Depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the Depolarization Wave in the mouse embryo by showing that the widely propagating Wave appeared independently of the localized spontaneous activity detected previously with Ca(2+) imaging. Furthermore, we mapped the origin of the Depolarization Wave and revealed that the Wave generator moved from the rostral spinal cord to the caudal cord as development proceeded, and was later replaced with mature rhythmogenerators. The present study, together with an accompanying paper that describes pharmacological properties of the mouse Depolarization Wave, shows that a synchronized Wave with common characteristics is expressed in different species, suggesting fundamental roles in neural development.
Tomoharu Nakamori - One of the best experts on this subject based on the ideXlab platform.
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pharmacological mechanisms underlying switching from the large scale Depolarization Wave to segregated activity in the mouse central nervous system
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: During the early development of the nervous system, synchronized activity is observed in a variety of structures, and is considered to play a fundamental role in neural development. One of the most striking examples of such activity is the Depolarization Wave reported in chick and rat embryos. In the accompanying paper (Momose-Sato et al., 2012), we have demonstrated that a Depolarization Wave is also present in the mouse embryo by showing large-scale optical Waves, which spread remarkably over the central nervous system, including the spinal cord, hindbrain, cerebellum, midbrain, and forebrain. In the present study, we examined the pharmacological nature of the mouse Depolarization Wave and its developmental changes. We show here that two types of switching in pharmacological characteristics occur during development. One is that the Depolarization Wave is strongly dependent on nicotinic acetylcholine receptors during the early developmental stage [embryonic day (E)11-12], but is dominated by glutamate at the later stage (E13 onwards). The second is that γ-aminobutyric acid (GABA), which acts as an excitatory mediator of the Depolarization Wave during the early phase, becomes an inhibitory modulator by E14. These changes seemed to occur earlier in the hindbrain than in the spinal cord. Furthermore, we show that the second switch causes the loss of synchronization over the network, resulting in the disappearance of the Depolarization Wave and segregation of the activity into discrete regions of the medulla and spinal cord. We suggest that pharmacological switching is a possible mechanism underlying replacement of the primordial correlated network by a mature neuronal circuit.
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spontaneous Depolarization Wave in the mouse embryo origin and large scale propagation over the cns identified with voltage sensitive dye imaging
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we have revealed previously that this correlated activity is a widely propagating Wave of neural Depolarization, which we termed the Depolarization Wave. We have observed in the chick and rat embryos that the activity spread over an extensive region of the CNS, including the spinal cord, hindbrain, cerebellum, midbrain and forebrain. One important consideration is whether a Depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the Depolarization Wave in the mouse embryo by showing that the widely propagating Wave appeared independently of the localized spontaneous activity detected previously with Ca(2+) imaging. Furthermore, we mapped the origin of the Depolarization Wave and revealed that the Wave generator moved from the rostral spinal cord to the caudal cord as development proceeded, and was later replaced with mature rhythmogenerators. The present study, together with an accompanying paper that describes pharmacological properties of the mouse Depolarization Wave, shows that a synchronized Wave with common characteristics is expressed in different species, suggesting fundamental roles in neural development.
Andrew E. Pollard - One of the best experts on this subject based on the ideXlab platform.
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A Model Study of Intramural Dispersion of Action Potential Duration in the Canine Pulmonary Conus
Annals of Biomedical Engineering, 1998Co-Authors: Adam W. Cates, Andrew E. PollardAbstract:Regional gradients of action potential duration (APD) due to electrophysiological differences between endocardial, midmyocardial, and epicardial myocytes may exist across the ventricular wall. In addition, activation sequence-induced gradients of APD may occur if intramural fiber rotation accelerates or decelerates the Depolarization Wave front. To investigate relative contributions of regional and activation sequence-induced gradients to intramural APD dispersion, we simulated action potential propagation in two-dimensional models with idealized geometries representing the canine pulmonary conus. Ionic currents for endocardial myocytes were described using the Luo–Rudy membrane equations. Modifications to I_Ks approximated action potentials of epicardial and midmyocardial cells. Spatial coupling was modeled with a bidomain representation of tissue structure that included unequal anisotropic conductivity ratios. Activation sequence-induced gradients reached 69 ms cm−1 during a nonuniform activation sequence where the change in orientation between endocardial and epicardial fibers accelerated the Depolarization Wave front. Regional gradients reached 133 ms cm^−1 at the boundary between endocardial and midmyocardial cells. When regional and activation sequence-induced gradients were oriented in opposite directions, overall APD dispersion decreased. When the gradients were oriented in the same direction, overall dispersion measured as high as 202 ms cm^−1. This gradient exceeded values previously estimated as sufficient to induce cardiac arrhythmia during premature stimulation and suggests that regional and activation sequence-induced gradients increase arrhythmia vulnerability in the presence of other arrhythmogenic conditions. © 1998 Biomedical Engineering Society. PAC98: 8710+e, 8722Fy
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A model study of intramural dispersion of action potential duration in the canine pulmonary conus.
Annals of Biomedical Engineering, 1998Co-Authors: Adam W. Cates, Andrew E. PollardAbstract:Regional gradients of action potential duration (APD) due to electrophysiological differences between endocardial, midmyocardial, and epicardial myocytes may exist across the ventricular wall. In addition, activation sequence-induced gradients of APD may occur if intramural fiber rotation accelerates or decelerates the Depolarization Wave front. To investigate relative contributions of regional and activation sequence-induced gradients to intramural APD dispersion, we simulated action potential propagation in two-dimensional models with idealized geometries representing the canine pulmonary conus. Ionic currents for endocardial myocytes were described using the Luo–Rudy membrane equations. Modifications to IKs approximated action potentials of epicardial and midmyocardial cells. Spatial coupling was modeled with a bidomain representation of tissue structure that included unequal anisotropic conductivity ratios. Activation sequence-induced gradients reached 69 ms cm−1 during a nonuniform activation sequence where the change in orientation between endocardial and epicardial fibers accelerated the Depolarization Wave front. Regional gradients reached 133 ms cm−1 at the boundary between endocardial and midmyocardial cells. When regional and activation sequence-induced gradients were oriented in opposite directions, overall APD dispersion decreased. When the gradients were oriented in the same direction, overall dispersion measured as high as 202 ms cm−1. This gradient exceeded values previously estimated as sufficient to induce cardiac arrhythmia during premature stimulation and suggests that regional and activation sequence-induced gradients increase arrhythmia vulnerability in the presence of other arrhythmogenic conditions. © 1998 Biomedical Engineering Society.
Yoko Momose-sato - One of the best experts on this subject based on the ideXlab platform.
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Origin of the earliest correlated neuronal activity in the chick embryo revealed by optical imaging with voltage-sensitive dyes
European Journal of Neuroscience, 2008Co-Authors: Yoko Momose-sato, Hiraku Mochida, Masae KinoshitaAbstract:Spontaneous correlated neuronal activity during early development spreads like a Wave by recruiting a large number of neurons, and is considered to play a fundamental role in neural development. One important and as yet unresolved question is where the activity originates, especially at the earliest stage of Wave expression. In other words, which part of the brain differentiates first as a source of the correlated activity, and how does it change as development proceeds? We assessed this issue by examining the spatiotemporal patterns of the Depolarization Wave, the optically identified primordial correlated activity, using the optical imaging technique with voltage-sensitive dyes. We surveyed the region responsible for the induction of the evoked and spontaneous Depolarization Waves in chick embryos, and traced its developmental changes. The results showed that the Wave initially originated in a restricted area near the obex and was generated by multiple regions at later stages. We suggest that the upper cervical cord/lower medulla near the obex is the kernel that differentiates first as the source of the correlated activity, and that regional and temporal differences in neuronal excitability might underlie the developmental profile of Wave generation in early chick embryos.
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Spontaneous Depolarization Waves of multiple origins in the embryonic rat CNS
European Journal of Neuroscience, 2007Co-Authors: Yoko Momose-sato, Katsushige Sato, Masae KinoshitaAbstract:During development, correlated neuronal activity plays an important role in the establishment of the central nervous system (CNS). We have previously reported that a widely propagating correlated neuronal activity, termed the Depolarization Wave, is evoked by various sensory inputs. A remarkable feature of the Depolarization Wave is that it spreads broadly through the brain and spinal cord. In the present study, we examined whether the Depolarization Wave occurs spontaneously in the embryonic rat CNS and, if so, where it originates. In E15-16 rat embryos, spontaneous optically-revealed signals appeared in association with the rhythmic discharges of cranial motoneurons and propagated widely with similar characteristics to the evoked Depolarization Wave. At E15, the spontaneous Wave mostly originated in the cervical to upper lumbar cords. At E16, the Wave was predominantly generated in the lumbosacral cord although a Wave associated with the second oscillatory burst was initiated in the rostral cord. At E16, a few Waves also originated in the rostral ventrolateral medulla and the dorsomedial pons. When the influence of the caudal cord was removed by transecting the spinal cord, the contribution of the medulla and pons became more significant. These results show that the Depolarization Wave can be triggered by the spontaneous activity of multiple neuronal populations which are distributed widely from the pons to the lumbosacral cord, although the spinal cord usually plays a predominant role. This network possibly works as a self-distributing system that maintains the incidence and complicated patterns of the correlated activity in the developing CNS.
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Depolarization Waves in the embryonic CNS triggered by multiple sensory inputs and spontaneous activity: optical imaging with a voltage-sensitive dye.
Neuroscience, 2003Co-Authors: Yoko Momose-sato, Hiraku Mochida, Shinichi Sasaki, Katsushige SatoAbstract:Abstract Previously, we discovered a novel type of Depolarization Wave in the embryonic chick brain by using a multiple-site optical recording technique with a fast voltage-sensitive dye. This Depolarization Wave traveled widely over almost all the region of the CNS. This profile has raised the possibility that the Depolarization Wave plays some global roles in development of the CNS, rather than contributing to a specific neuronal circuit formation. To obtain more information concerning this issue, in the present study, we examined whether the Depolarization Wave was triggered by various types of peripheral nerve inputs. Stimulation applied to the vagus, glossopharyngeal, cochlear and trigeminal nerves evoked widely spreading Depolarization Waves with similar spatiotemporal distribution patterns. The developmental sequence of Wave expression was parallel to the development of the excitatory postsynaptic potentials in each sensory nucleus. The Depolarization Wave was accompanied by a Ca 2+ -Wave, suggesting that not only electrical synchrony, but also large-scale Ca 2+ -transients may affect developmental processes in the embryonic brain. Furthermore, we found that the Depolarization Wave also occurred spontaneously. The Waveform and distribution patterns of the spontaneous optical signals were similar to those of the cranial nerve-evoked Depolarization Wave. These results demonstrated that the Depolarization Wave in the embryonic chick brain is triggered by multiple sources of external and endogenous activity. This profile supports the idea that this Depolarization Wave may not serve as a simple regulator of specific neuronal circuit formation, but might play more global roles in CNS development.
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Optical imaging of spreading Depolarization Waves triggered by spinal nerve stimulation in the chick embryo: possible mechanisms for large-scale coactivation of the central nervous system.
European Journal of Neuroscience, 2001Co-Authors: Hiraku Mochida, Katsushige Sato, Shinichi Sasaki, Kohtaro Kamino, Yoshiyasu Arai, Yoko Momose-satoAbstract:: Using a multiple-site optical recording technique with a voltage-sensitive dye, we found that widely spreading Depolarization Waves were evoked by dorsal root stimulation in embryonic chick spinal cords. Spatiotemporal maps of the Depolarization Waves showed that the signals were mainly distributed in the ventral half of the slice, with the highest activity in the ventrolateral area. The propagation velocity of the Waves was estimated to be in the order of mm/s. Depolarization Waves were evoked in the ventral root-cut preparation, but not in the dorsal root-cut preparation, suggesting that the Wave was triggered by synaptic inputs from the primary afferents, and that activation of the motoneurons was not essential for Wave generation. In intact spinal cord-brain preparations, the Depolarization Wave propagated rostrally and caudally for a distance of several spinal segments in normal Ringer's solution. In a Mg(2+)-free solution, the amplitude and extent of the signals were markedly enhanced, and the Depolarization Wave triggered in the cervical spinal cord propagated to the brainstem and the cerebellum. The Depolarization Wave demonstrated here had many similarities with the vagus nerve-evoked Depolarization Wave reported previously. The results suggest that functional cell-to-cell communication systems mediated by the Depolarization Wave are widely generated in the embryonic central nervous system, and could play a role in large-scale coactivation of the neurons in the spinal cord and brain.
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Spreading Depolarization Waves triggered by vagal stimulation in the embryonic chick brain: optical evidence for intercellular communication in the developing central nervous system.
Neuroscience, 2001Co-Authors: Yoko Momose-sato, Katsushige Sato, Hiraku Mochida, Shinichi Sasaki, Itaru Yazawa, Kohtaro KaminoAbstract:Abstract Throughout experiments on multiple-site voltage-sensitive dye recordings of neural activity in embryonic chick brain preparations, we have found a novel type of Depolarization Waves which spread widely from the brainstem to the whole brain region at a rapid rate (mm/s). This Depolarization Wave was triggered by glutamate-mediated postsynaptic potentials and was especially correlated to N -methyl- d -aspartate receptor function. Evidence that the spreading Depolarization Wave is eliminated by octanol or 18β-glycyrrhetinic acid suggests that the Depolarization Wave depends on functions of gap junctions. The profile obtained with Ca 2+ -imaging experiments also suggests that the propagation of the Depolarization Wave is accompanied by a calcium Wave. These results provide new evidence for intercellular functional communication between neural cells in the vertebrate central nervous system during embryonic development.