Neurons in the dentate hilus or area CA3c of rat hippocampal slices were recorded intracellularly with electrodes containing the fluorescent dye Lucifer yellow. Stimulation of perforant path fibers in the molecular layer of the fascia dentata strongly excited most hilar neurons, with a much lower threshold for action potential generation than granule cells and area CA3c pyramidal cells that wer...

The selective hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker 4-(N-ethyl-N-phenylamino)-1,2-dimethyl-6-(methylamino) pyrimidinium chloride (ZD7288) blocks the induction of long-term potentiation in the perforant path-CA3 region in rat hippocampus in vivo. To explore the mechanisms underlying the action of ZD7288, we recorded excitatory postsynaptic potentials in perfor...

Bath applied monoamines dopamine (DA), serotonin (5-HT), and noradrenaline (NE) strongly suppress the perforant path (PP) input to CA1 hippocampal region with very little effect on the Schaffer collaterals (SC) input (Otmakhova and Lisman, 2000). The effect of DA action on PP field EPSP (fEPSP) has been characterized in detail (Otmakhova and Lisman, 1999), but relatively little is known about t...

Zhao, Danyun, Joseph B. Watson, and Cui-Wei Xie. Amyloid prevents activation of calcium/calmodulin-dependent protein kinase II and AMPA receptor phosphorylation during hippocampal long-term potentiation. J Neurophysiol 92: 2853–2858, 2004. First published June 22, 2004; 10.1152/jn.00485.2004. Accumulation of amyloid -peptides (A ) in the brain has been linked with memory loss in Alzheimer’s dis...

Synaptic plasticity comprises a cellular mechanism through which the hippocampus most likely enables memory formation. Neuromodulation, related to arousal, is a key aspect in information storage. The activation of locus coeruleus (LC) neurons by novel experience leads to noradrenaline release in the hippocampus at the level of the dentate gyrus (DG). We explored whether synaptic plasticity in t...

Several lines of evidence indicate that LTP in the hippocampus is associated with a change in the properties of postsynaptic glutamate receptors. In the present study, we used quantitative autoradiography to examine the binding properties of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) and N-methyl-D-aspartate subclasses of glutamate receptors in frozen brain sections obtain...

Unilateral transection of the excitatory perforant path results in the acute deafferentation of a segregated zone on the distal dendrites of hippocampal dentate gyrus granule cells (i.e., outer molecular layer), followed by sprouting, reactive synaptogenesis, and a return of physiological and behavioral function. To investigate cellular mechanisms underlying NMDA receptor plasticity in response...

The present study examined the role of ovarian steroids in contextual fear conditioning and hippocampal synaptic plasticity in female rats. In experiment 1, adult female rats were ovariectomized and submitted to contextual fear conditioning, a procedure in which rats received unsignaled footshock in a novel observation chamber; freezing behavior served as the measure of conditional fear. Ovarie...

GAZZALEY, A. H., M. M. THAKKER, P. R. HOF, J. H. MORRISON. Preserved number of entorhinal cortex layer II neurons in aged macaque monkeys. NEUROBIOL AGING 18(5) 549–553, 1997.—The perforant path, which consists of the projection from the layer II neurons of the entorhinal cortex to the outer molecular layer of the dentate gyrus, is a critical circuit involved in learning and memory formation. A...

Strong constraints on the neural mechanisms underlying the formation of place fields in the rodent hippocampus come from the systematic changes in spatial activity patterns that are consequent on systematic environmental manipulations. We describe an attractor network model of area CA3 in which local, recurrent, excitatory, and inhibitory interactions generate appropriate place cell representat...