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Rapid Astrocyte Calcium Signals Correlate with Neuronal Activity and Onset of the Hemodynamic Response In Vivo

2007; Society for Neuroscience; Volume: 27; Issue: 23 Linguagem: Inglês

10.1523/jneurosci.4801-06.2007

1529-2401

Ian R. Winship, Nathan Plaa, Timothy H. Murphy,

Neural dynamics and brain function

Elevation of intracellular Ca 2+ in astrocytes can influence cerebral microcirculation and modulate synaptic transmission. Recently, in vivo imaging studies identified delayed, sensory-driven Ca 2+ oscillations in cortical astrocytes; however, the long latencies of these Ca 2+ signals raises questions in regards to their suitability for a role in short-latency modulation of cerebral microcirculation or rapid astrocyte-to-neuron communication. Here, using in vivo two-photon Ca 2+ imaging, we demonstrate that ∼5% of sulforhodamine 101-labeled astrocytes in the hindlimb area of the mouse primary somatosensory cortex exhibit short-latency (peak amplitude ∼0.5 s after stimulus onset), contralateral hindlimb-selective sensory-evoked Ca 2+ signals that operate on a time scale similar to neuronal activity and correlate with the onset of the hemodynamic response as measured by intrinsic signal imaging. The kinetics of astrocyte Ca 2+ transients were similar in rise and decay times to postsynaptic neuronal transients, but decayed more slowly than neuropil Ca 2+ transients that presumably reflect presynaptic transients. These in vivo findings suggest that astrocytes can respond to sensory activity in a selective manner and process information on a subsecond time scale, enabling them to potentially form an active partnership with neurons for rapid regulation of microvascular tone and neuron–astrocyte network properties.