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Analyzing the Size, Shape, and Directionality of Networks of Coupled Astrocytes
Published on: October 4, 2018
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Astrocytes regulate cortical state switching in vivo.
Kira E Poskanzer1, Rafael Yuste2
1Department of Biological Sciences, Columbia University, New York, NY 10027 kira.poskanzer@ucsf.edu.
Summary
Astrocytes, a type of brain cell, can trigger slow brain oscillations by releasing glutamate. This finding reveals astrocytes
Area of Science:
- Neuroscience
- Astrocyte Biology
- Cortical Circuitry
Background:
- Astrocytes' role in neuronal function is increasingly recognized but their circuit-level function remains debated.
- The slow-oscillation state, crucial for sleep and memory, is a neocortical rhythm characterized by synchronized neuronal firing.
Purpose of the Study:
- To investigate the role of astrocytes in controlling neocortical circuit states.
- To determine if astrocytes can initiate shifts to the slow-oscillation state.
Main Methods:
- In vivo two-photon calcium imaging of neocortical astrocytes.
- Simultaneous electrophysiological and optical monitoring of neuronal circuit activity.
- Optogenetic manipulation of astrocyte activity.
- Two-photon imaging of extracellular glutamate.
Main Results:
- Astrocytic calcium activity preceded spontaneous shifts to the slow-oscillation state.
- Optogenetic activation of astrocytes induced the slow-oscillation state in the local neuronal circuit.
- Astrocytic glutamate transients coincided with shifts to the synchronized state and could be induced by astrocyte activation.
Conclusions:
- Astrocytes can trigger the low-frequency synchronized state of cortical circuits.
- Astrocytes play a causal role in controlling cortical synchronizations via extracellular glutamate modulation.
