title: Signal transfer within a cultured asymmetric cortical neuron circuit.
abstract: OBJECTIVE
  Simplified neuronal circuits are required for investigating information representation in nervous systems and for validating theoretical neural network models. Here, we developed patterned neuronal circuits using micro fabricated devices, comprising a micro-well array bonded to a microelectrode-array substrate.
  
  
  METHODS
  The micro-well array consisted of micrometre-scale wells connected by tunnels, all contained within a silicone slab called a micro-chamber. The design of the micro-chamber confined somata to the wells and allowed axons to grow through the tunnels bidirectionally but with a designed, unidirectional bias. We guided axons into the point of the arrow structure where one of the two tunnel entrances is located, making that the preferred direction.
  
  
  RESULTS
  When rat cortical neurons were cultured in the wells, their axons grew through the tunnels and connected to neurons in adjoining wells. Unidirectional burst transfers and other asymmetric signal-propagation phenomena were observed via the substrate-embedded electrodes. Seventy-nine percent of burst transfers were in the forward direction. We also observed rapid propagation of activity from sites of local electrical stimulation, and significant effects of inhibitory synapse blockade on bursting activity.
  
  
  CONCLUSIONS
  These results suggest that this simple, substrate-controlled neuronal circuit can be applied to develop in vitro models of the function of cortical microcircuits or deep neural networks, better to elucidate the laws governing the dynamics of neuronal networks.
authors.affiliation: Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Room 1122, Faculty of Engineering Bldg. 14, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. Japan Society for the Promotion of Science (JSPS), Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Isomura
authors.forename: Kenta
authors.initials: K
authors.lastname: Shimba
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Takayama
authors.forename: Akimasa
authors.initials: A
authors.lastname: Takeuchi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kotani
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Jimbo
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001369:Axons / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D009415:Nerve Net / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D051381:Rats