title: Synchronization through nonreciprocal connections in a hybrid hippocampus microcircuit.
abstract: Synchronization among neurons is thought to arise from the interplay between excitation and inhibition; however, the connectivity rules that contribute to synchronization are still unknown. We studied these issues in hippocampal CA1 microcircuits using paired patch clamp recordings and real time computing. By virtually connecting a model interneuron with two pyramidal cells (PCs), we were able to test the importance of connectivity in synchronizing pyramidal cell activity. Our results show that a circuit with a nonreciprocal connection between pyramidal cells and no feedback from PCs to the virtual interneuron produced the greatest level of synchronization and mutual information between PC spiking activity. Moreover, we investigated the role of intrinsic membrane properties contributing to synchronization where the application of a specific ion channel blocker, ZD7288 dramatically impaired PC synchronization. Additionally, background synaptic activity, in particular arising from NMDA receptors, has a large impact on the synchrony observed in the aforementioned circuit. Our results give new insights to the basic connection paradigms of microcircuits that lead to coordination and the formation of assemblies.
authors.affiliation: Neurodynamics Lab, Department of Neuroscience, Uppsala University Uppsala, Sweden ; Brain Institute, Federal University of Rio Grande do Norte Natal, Brazil.
authors.forename: Markus M
authors.initials: MM
authors.lastname: Hilscher
authors.forename: Katarina E
authors.initials: KE
authors.lastname: Leão
authors.forename: Richardson N
authors.initials: RN
authors.lastname: Leão
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D006624:Hippocampus / Q000166:cytology* / Q000502:physiology*; D053444:Inhibitory Postsynaptic Potentials / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009415:Nerve Net / Q000166:cytology* / Q000502:physiology*; D009924:Organ Culture Techniques; D017966:Pyramidal Cells / Q000502:physiology
keywords: AMPA; Ih; NMDA; dynamic clamp; hippocampus; synchronization