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Extracellular GABA assisting in organizing dynamic cell assemblies to shorten reaction time to sensory stimulation

  • Ryuta Sakamoto
  • Rikiya Kameno
  • Taira Kobayashi
  • Asahi Ishiyama
  • Kazuo Watanabe
  • Osamu HoshinoEmail author
Original Article

Abstract

Until recently, glia, which exceeds the number of neurons, was considered to only have supportive roles in the central nervous system, providing homeostatic controls and metabolic supports. However, recent studies suggest that glia interacts with neurons and plays active roles in information processing within neuronal circuits. To elucidate how glia contributes to neuronal information processing, we simulated a sensory neuron–glia (neuron–astrocyte) network model. It was investigated in association with ambient (extracellular) GABA level, because the astrocyte has a major role in removing extracellular GABA molecules. In the network model, transporters, embedded in plasma membranes of astrocytes, modulated local ambient GABA levels by actively removing extracellular GABA molecules which persistently acted on receptors in membranes outside synapses and provided pyramidal cells with inhibitory currents. Gap-junction coupling between astrocytes mediated a concordant decrease in local ambient GABA levels, which solicited a prompt population response of pyramidal cells (i.e., activation of an ensemble of pyramidal cells) to a sensory stimulus. As a consequence, the reaction time of a motor network, to which axons of pyramidal cells of the sensory network project, to the sensory stimulus was shortened. We suggest that the astrocytic gap-junction coupling may assist in organizing dynamic cell assemblies by coordinating a reduction in local ambient GABA levels, thereby shortening reaction time to sensory stimulation.

Keywords

Astrocytic gap junction GABA transport Ambient GABA Sensory information processing Reaction time 

Notes

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Ryuta Sakamoto
    • 1
  • Rikiya Kameno
    • 2
  • Taira Kobayashi
    • 1
  • Asahi Ishiyama
    • 3
  • Kazuo Watanabe
    • 2
  • Osamu Hoshino
    • 1
    • 2
    Email author
  1. 1.Department of Intelligent Systems EngineeringIbaraki UniversityHitachiJapan
  2. 2.Southern Tohoku Research Institute for NeuroscienceSouthern Tohoku General HospitalKoriyamaJapan
  3. 3.Production Engineering HQTDK CorporationNikaho-shiJapan

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