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Structure and function of axo-axonic inhibition
Casey M Schneider-Mizell1, Agnes L Bodor1, Forrest Collman1
1Allen Institute for Brain Sciences, Seattle, United States.
Elife
|December 1, 2021
Summary
Chandelier cells in the visual cortex show variable synaptic connections to pyramidal neurons, influencing circuit function. Their correlated activity suggests a role in arousal and circuit-wide signaling.
Area of Science:
- Neuroscience
- Cortical circuits
- Cellular connectivity
Background:
- Mammalian cortical inhibitory neurons display diverse characteristics.
- Understanding inhibitory cell connectivity at synaptic resolution is limited.
- Chandelier cells' precise role in cortical circuits remains unclear.
Purpose of the Study:
- Investigate chandelier cell connectivity with pyramidal neurons in mouse visual cortex.
- Relate synaptic input to target neuron properties and circuit function.
- Examine chandelier cell activity and its correlation with arousal.
Main Methods:
- Large-scale electron microscopy for dense synaptic reconstruction.
- Functional imaging and biophysical simulations.
- In vivo cell-type-specific calcium imaging in awake mice.
Main Results:
- Mapped complete chandelier cell input onto 153 pyramidal neurons.
- Synapse number variability was high and correlated with target neuron structure.
- Chandelier cell activity was highly correlated and linked to pupil dilation (arousal).
Conclusions:
- Chandelier cell connectivity is highly variable and neuron-specific.
- Axo-axonic inhibition effectively controls excitatory output during co-activity.
- Chandelier cells provide a circuit-wide signal modulated by target neuron properties and arousal.
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