title: [Visualization of multineuronal spike activity].
abstract: The neuronal network is a computing system that transforms input to output. This computation involves complex nonlinear processes that are carried out with polysynaptic feedforward and feedback microcircuitry. Thus it cannot be assessed by isolating responses of single neurons or by averaging multineuronal responses. To solve this problem, functional multineuron calcium imaging (fMCI) is a promising option. This is a large-scale recording technique that simultaneously monitors the spatiotemporal patterns of spikes emitted by hundreds of neurons with single-cell resolution. Here, we review the availability and actual applications of fMCI. Using fMCI, we attempt to understand the manner in which information is processed in the hippocampal networks. The hippocampus receives information from the cortex; relays it through the dentate gyrus (DG), Cornu Ammonis (CA) 3, and then CA1; and sends it back to the cortex. We placed 2 stimulation electrodes (Stim A and Stim B) in the DG granule cell layer of cultured hippocampal networks and monitored the firing activity of a population of CA1 pyramidal neurons. In this experimental design, the hippocampal polysynaptic network is regarded as a huge arithmetic operator that converts DG inputs to CA1 outputs. We found that the hippocampal polysynaptic network functions as a complex parallel and distributed processing system.
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Kimura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ikegaya
mesh_terms: D000200:Action Potentials; D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D018891:Dentate Gyrus / Q000502:physiology; D003952:Diagnostic Imaging / Q000379:methods*; D006624:Hippocampus / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology; D009435:Synaptic Transmission