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On the linear track, the recent firing sequences of CA1 place cells recur during sharp wave/ripple patterns (SWRs) in a reverse temporal order [Foster & Wilson (2006) Nature, 440, 680-683]. We have found similar reverse-order reactivation during SWRs in open-field exploration where the firing sequence of cells varied before each SWR. Both the onset times(More)
Hippocampal place cells that fire together within the same cycle of theta oscillations represent the sequence of positions (movement trajectory) that a rat traverses on a linear track. Furthermore, it has been suggested that the encoding of these and other types of temporal memory sequences is organized by gamma oscillations nested within theta(More)
Grid cells in the medial entorhinal cortex (MEC) generate metric spatial representations. Recent attractor-network models suggest an essential role for GABAergic interneurons in the emergence of the grid-cell firing pattern through recurrent inhibition dependent on grid-cell phase. To test this hypothesis, we studied identified parvalbumin-expressing(More)
Temporal coding is a means of representing information by the time, as opposed to the rate, at which neurons fire. Evidence of temporal coding in the hippocampus comes from place cells, whose spike times relative to theta oscillations reflect a rat's position while running along stereotyped trajectories. This arises from the backwards shift in cell firing(More)
RATIONALE The parasympathetic reduction in heart rate involves the sequential activation of m2 muscarinic cholinergic receptors (m(2)Rs), pertussis toxin-sensitive (Gi/o) heterotrimeric G proteins, and the atrial potassium channel I(KACh). Molecular mechanisms regulating this critical signal transduction pathway are not fully understood. OBJECTIVE To(More)
The hippocampus is thought to be involved in episodic memory formation by reactivating traces of waking experience during sleep. Indeed, the joint firing of spatially tuned pyramidal cells encoding nearby places recur during sleep. We found that the sleep cofiring of rat CA1 pyramidal cells encoding similar places increased relative to the sleep session(More)
Reduction of excitatory currents onto GABAergic interneurons in the forebrain results in impaired spatial working memory and altered oscillatory network patterns in the hippocampus. Whether this phenotype is caused by an alteration in hippocampal interneurons is not known because most studies employed genetic manipulations affecting several brain regions.(More)
GABAergic interneurons in the hippocampus coordinate neuronal activity that gives rise to network oscillations. In this article we present advances in our understanding of how different classes of hippocampal interneurons contribute to distinct hippocampal network oscillations. We focus on two main experimental approaches that were recently applied in awake(More)
Gap junctions containing connexin 36 electrically couple interneurons in many brain regions and synchronize their activity. We used connexin-36 knock-out mice (Cx36(-/-)) to study the importance of electrical coupling between interneurons for spatial coding in the hippocampus and for different forms of hippocampus-dependent spatial memory. Recordings in(More)
The type 5 G protein beta subunit (Gbeta5) can form complexes with members of the regulator of G protein signaling 7 (RGS7) family, but its relevance to neuronal G protein signaling is unclear. We found that mouse RGS7-Gbeta5 complexes bound to G protein-gated potassium channels and facilitated their functional coupling to GABA(B) receptors in neurons. Our(More)