Astrocytes discriminate and selectively respond to the activity of a subpopulation of neurons within the barrel cortex


  • C.G. Schipke
  • B. Haas
  • H. Kettenmann


  • Cerebral Cortex


  • Cereb Cortex 18 (10): 2450-2459


  • Sensory information from single whiskers in rodents projects to defined morphological units in the cortex, the barrels. We found that astrocytes selectively respond with an increase in the cytosolic Ca(2+) concentration to activation of layer 4 neurons, the input cells of the barrel columns. The neuronal Ca(2+) signal also spread across barrel column borders mainly in layer 2/3, but the glutamate-mediated astrocyte response stayed restricted to the barrel column. In contrast, when interfering with inhibitory pathways by blocking either purinergic, adenosine or gamma-aminobutyric acid(A) receptors, the stimulation activated a Ca(2+) response in a much larger astrocyte population no longer restricted to the borders of the barrel column. We also observed spontaneous and evoked Ca(2+) activity in the synaptic target cells of layer 4 neurons, the layer 2/3 pyramidal cells, but again, we never recorded Ca(2+) responses in astrocytes following activity in this neuronal population. Our data show that astrocytes can discriminate and selectively respond to the activity of a subpopulation of excitatory neurons within a given brain region. This selectivity in the astrocyte response describes a new level of complexity and integration in the reaction of astrocytes to neuronal activity.