title: Rapid desynchronization of an electrically coupled interneuron network with sparse excitatory synaptic input.
abstract: Electrical synapses between interneurons contribute to synchronized firing and network oscillations in the brain. However, little is known about how such networks respond to excitatory synaptic input. To investigate this, we studied electrically coupled Golgi cells (GoC) in the cerebellar input layer. We show with immunohistochemistry, electron microscopy, and electrophysiology that Connexin-36 is necessary for functional gap junctions (GJs) between GoC dendrites. In the absence of coincident synaptic input, GoCs synchronize their firing. In contrast, sparse, coincident mossy fiber input triggered a mixture of excitation and inhibition of GoC firing and spike desynchronization. Inhibition is caused by propagation of the spike afterhyperpolarization through GJs. This triggers network desynchronization because heterogeneous coupling to surrounding cells causes spike-phase dispersion. Detailed network models predict that desynchronization is robust, local, and dependent on synaptic input properties. Our results show that GJ coupling can be inhibitory and either promote network synchronization or trigger rapid network desynchronization depending on the synaptic input.
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
authors.forename: Koen
authors.initials: K
authors.lastname: Vervaeke
authors.forename: Andrea
authors.initials: A
authors.lastname: Lorincz
authors.forename: Padraig
authors.initials: P
authors.lastname: Gleeson
authors.forename: Matteo
authors.initials: M
authors.lastname: Farinella
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Nusser
authors.forename: R Angus
authors.initials: RA
authors.lastname: Silver
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002525:Cerebellar Cortex / Q000166:cytology* / Q000502:physiology*; D003344:Cortical Synchronization; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D007395:Interneurons / Q000502:physiology*; D008297:Male; D051379:Mice; D009415:Nerve Net / Q000166:cytology* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000502:physiology*; D013997:Time Factors