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A network of fast-spiking cells in the neocortex connected by electrical synapses

Abstract

Encoding of information in the cortex is thought to depend on synchronous firing of cortical neurons1,2. Inhibitory neurons are known to be critical in the coordination of cortical activity3,4,5, but how interaction among inhibitory cells promotes synchrony is not well understood4,6,7,8,9,10,11,12. To address this issue directly, we have recorded simultaneously from pairs of fast-spiking (FS) cells, a type of γ-aminobutyric acid (GABA)-containing neocortical interneuron13. Here we report a high occurrence of electrical coupling among FS cells. Electrical synapses were not found among pyramidal neurons or between FS cells and other cortical cells. Some FS cells were interconnected by both electrical and GABAergic synapses. We show that communication through electrical synapses allows excitatory signalling among inhibitory cells and promotes their synchronous spiking. These results indicate that electrical synapses establish a network of fast-spiking cells in the neocortex which may play a key role in coordinating cortical activity.

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Figure 1: Specific electrical coupling among fast-spiking cells.
Figure 2: GABA-mediated synaptic transmission and electrical coupling among FS cells.
Figure 3: Electrical coupling behaving as a low-pass filter.
Figure 4: Electrical coupling promoting simultaneous spiking.

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Acknowledgements

We thank M. Chang for technical assistance. S.H. was supported by an NIH grant.

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Correspondence to Shaul Hestrin.

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Galarreta, M., Hestrin, S. A network of fast-spiking cells in the neocortex connected by electrical synapses. Nature 402, 72–75 (1999). https://doi.org/10.1038/47029

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