(V.B. Kazantsev, A.V. Semyanov, A.A. Lebedinsky, I. Bugrov) The project is devoted to the investigation of possible mechanisms of signal transmission control in neuronal network by the astrocytes. Calcium transients in astrocytes are associated with the release of neuroactive molecules (for example, glutamate, ATP or GABA) to extracellular space. Such release results in changing of neuron cell membrane excitability and the efficiency of synaptic transmission. Spatially inhomogeneous astrocyte activity patterns can potentially form corresponding profile of diffuse neurotransmitter that can influence signal propagation pathways in neuronal networks (A.V. Semyanov, 2007). The project has the following tasks:

  • Investigate formation of astrocytic activity patterns due to neuronal spiking (neglecting the influence of astrocytes to neurons);
  • Investigate influence of quasi-stationary astrocytic activity patterns on signal propagation in neuronal network (neglecting the feedback from neurons to astrocytes);
  • Investigate bidirectional neuron-astrocyte interaction.

Such tasks separation is possible due to drastically different time scales of neuronal and astrocyte signaling (1-40 msec – excitation propagation in neuronal network, >103 msec – astrocyte calcium transient duration).

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Fig. 1. Two-layer architecture of neuron-astrocyte network model. The lower layer describes astrocytes coupled via gap junctions, the upper layer shows synaptically coupled neuronal cells.

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Fig. 2. Signal pulse propagation in neuronal network guided by astrocyte activity pattern.