Electrically coupled inhibitory neurons

Gibson, JR. Beierlein, M. Connors, BW. (1999) Two networks of electrically coupled inhibitory neurons in neocortex. Nature 402: 75-79.


This is a fantastic paper showing how there are two electrically connected inhibitory circuits in the brain. One of the networks is made up of the FS cells, which are thought to be responsible for gamma. These cells are acting like a clock, and keep the pyramidal cells synchronized. The pryamidal cells will mainly only fire during the troughs of the inhibition.

Here you can see an experiment showing two cells coupled together. What's amazing is how precise the action potentials align. In the cross-correlogram the neurons have a 2ms synchrony. So the spikes align very well - especially with regard to a 25ms oscillation. 

This table shows the synaptic connectivity of a bunch of different cell types. For the FS cells 24/39 pairs have electrical synapses, so the whole network has strong coupling. These cells have chemical connections to RS (pyramidal) cells.