During active exploration, hippocampal neurons exhibit nested rhythmic activity at theta ( approximately 8 Hz) and gamma ( approximately 40 Hz) frequencies. Gamma rhythms may be generated locally by interactions within a class of interneurons mediating fast GABA(A) (GABA(A,fast)) inhibitory postsynaptic currents (IPSCs), whereas theta rhythms traditionally are thought to be imposed extrinsicall...

Hippocampal theta (5-10 Hz) and gamma (35-85 Hz) oscillations depend on an inhibitory network of GABAergic interneurons. However, the lack of methods for direct and cell-type-specific interference with inhibition has prevented better insights that help link synaptic and cellular properties with network function. Here, we generated genetically modified mice (PV-Deltagamma(2)) in which synaptic i...

Theta oscillations (4-12 Hz) are thought to provide a common temporal reference for the exchange of information among distant brain networks. On the other hand, faster gamma-frequency oscillations (30-160 Hz) nested within theta cycles are believed to underlie local information processing. Whether oscillatory coupling between global and local oscillations, as showcased by theta-gamma coupling, ...

Brain region coordination in learning Gamma-frequency oscillations have been hypothesized as a physiological mechanism of interregional communication the brain. However, until now, all supporting data correlational and thus indirect. Fernández-Ruiz et al. examined gamma-frequency activity spike coupling between entorhinal cortex hippocampal dentate gyrus during after selective perturbation timi...

Local circuits in the medial entorhinal cortex (mEC) and hippocampus generate gamma frequency population rhythms independently. Temporal interaction between these areas at gamma frequencies is implicated in memory-a phenomenon linked to activity of NMDA-subtype glutamate receptors. While blockade of NMDA receptors does not affect frequency of gamma rhythms in hippocampus, it exposes a second, l...

Hippocampal theta and gamma rhythms often occur together. While gamma activity is supposed to be generated intrahippocampally, the source of theta oscillations is still debated. Here, a network model of hippocampal inhibitory interneurons was capable of generating the gamma rhythm when responding to constant excitation. Adding a periodic term to this stimulation resulted in complex pattern gene...