A network of electrically coupled interneurons drives synchronized inhibition
in neocortex
Michael Beierlein1, 2, Jay R. Gibson1, 2
& Barry W. Connors1
1
Department of Neuroscience, Division of Biology &
Medicine, Box 1953, Brown University, Providence, Rhode
Island 02912, USA
2
The first two authors contributed equally to this work
Correspondence should be addressed to Barry W. Connors bwc@brown.edu
The neocortex has at least two different networks of electrically coupled
inhibitory interneurons: fast-spiking (FS) and low-threshold-spiking (LTS)
cells. Agonists of metabotropic glutamate or acetylcholine receptors induced
synchronized spiking and membrane fluctuations, with irregular or rhythmic
patterns, in networks of LTS cells. LTS activity was closely correlated with
inhibitory postsynaptic potentials in neighboring FS interneurons and excitatory
neurons. Synchronized LTS activity required electrical synapses, but not fast
chemical synapses. Tetanic stimulation of local circuitry induced effects
similar to those of metabotropic agonists. We conclude that an electrically
coupled network of LTS interneurons can mediate synchronized inhibition when
activated by modulatory neurotransmitters.
