Perfusion of rat brain slices with low millimole CsCl elicits slow oscillations of </=1 Hz in hippocampal CA1 pyramidal neurons. These oscillations are GABAA receptor-mediated hyperpolarizations that permit a coherent fire-pause pattern in a population of CA1 neurons. They can persist without the activation of ionotropic glutamate receptors but require adenosine-dependent inhibition of glutamat...

Transient global ischemia is a neuronal insult that induces delayed, selective death of hippocampal CA1 pyramidal neurons. A mechanism underlying ischemia-induced cell death is activation of the gene silencing transcription factor REST (repressor element-1 silencing transcription factor)/NRSF (neuron-restrictive silencing factor) and REST-dependent suppression of the AMPA receptor subunit GluR2...

Transient global ischemia induces selective delayed cell death, primarily of principal neurons in the hippocampal CA1. However, the molecular mechanisms underlying ischemia-induced cell death are as yet unclear. The present study shows that global ischemia triggers a pronounced and cell-specific reduction in GluR2 [the subunit that limits Ca(2+) permeability of alpha-amino-3-hydroxy-5-methyl-4-...

Hippocampal CA1 neurons are the most vulnerable to transient cerebral ischemia. However, the mechanism has not been fully understood. The level of mRNA for cytochrome C oxidase (COX) subunit I (COX-I), which is encoded by mitochondrial (mt) DNA, progressively decreased in the hippocampal CA1 neurons of gerbils from 3 h of reperfusion after 3.5 min of transient forebrain ischemia and completely ...

BACKGROUND The level of expression of functional α7-containing nicotinic acetylcholine receptors (nAChRs) in hippocampal CA1 pyramidal neurons is believed to be very low compared to hippocampal CA1 interneurons, and for many years this expression was largely overlooked. However, high densities of expression of functional α7-containing nAChRs in CA1 pyramidal neurons may not be necessary for tri...

Hippocampal CA1 and CA3 pyramidal neuron place cells encode the spatial location of an animal through localized firing patterns called "place fields." To explore the mechanisms that control place cell firing and their relationship to spatial memory, we studied mice with enhanced spatial memory resulting from forebrain-specific knockout of the HCN1 hyperpolarization-activated cation channel. HCN...

Transfer of neuronal patterns from the CA3 to CA1 region was studied by simultaneous recording of neuronal ensembles in the behaving rat. A nonlinear interaction among pyramidal neurons was observed during sharp wave (SPW)-related population bursts, with stronger synchrony associated with more widespread spatial coherence. SPW bursts emerged in the CA3a-b subregions and spread to CA3c before in...

The hippocampus receives two streams of information, spatial and nonspatial, via major afferent inputs from the medial (MEC) and lateral entorhinal cortexes (LEC). The MEC and LEC projections in the temporoammonic pathway are topographically organized along the transverse-axis of area CA1. The potential for functional segregation of area CA1, however, remains relatively unexplored. Here, we dem...

The hippocampus and the nearby medial temporal lobe structures are required for the formation, consolidation, and retrieval of episodic memories. Sensory information enters the hippocampus via two inputs from entorhinal cortex (EC): One input (perforant path) makes synapses on the dendrites of dentate granule cells as the first set of synapses in the trisynaptic circuit, the other (temporoammon...

Models of hippocampal function have proposed different functions for hippocampal regions CA3 and CA1, commonly proposing that CA1 performs a match-mismatch comparison of memory retrieval with sensory input. The study by I. Lee, M. R. Hunsaker, and R. P. Kesner (2005) tested these models using selective lesions of hippocampal subregions (see record 2005-01705-014). Their data suggest that CA3 an...