Degeneration of CA3-pyramidal neurons in hippocampus after intracerebroventricular kainic acid (KA) administration, a model of temporal lobe epilepsy, results in hyperexcitability within both dentate gyrus and the CA1 subfield. It also leads to persistent reductions in hippocampal glutamate decarboxylase (GAD) interneuron numbers without diminution in Nissl-stained interneuron numbers, indicati...

We have re-examined the hippocampal lamellar organization of the CA3-to-CA1 connection. Based on a new technique with electrophysiological quantification of Schaffer collateral density, and a review of recent literature, we conclude that the lamellar organization remains a useful concept for understanding hippocampal connectivity. Using a sheet-like hippocampal preparation, containing the whole...

objective(s) nicotinic acetylcholine receptors (nachrs) regulate epileptiform activity and produce a sustained pro-epileptogenic action within the hippocampal slices. in the present study, we investigated the effect of nachrs on evoked glutamatergic synaptic transmission in area ca3 and ca1 of rat hippocampal slices to identify possible excitatory circuits through which activation of nachrs pro...

The theta rhythm appears in the rat hippocampal electroencephalogram during exploration and shows phase locking to stimulus acquisition. Lesions that block theta rhythm impair performance in tasks requiring reversal of prior learning, including reversal in a T-maze, where associations between one arm location and food reward need to be extinguished in favor of associations between the opposite ...

Objective(s) Nicotinic acetylcholine receptors (nAChRs) regulate epileptiform activity and produce a sustained pro-epileptogenic action within the hippocampal slices. In the present study, we investigated the effect of nAChRs on evoked glutamatergic synaptic transmission in area CA3 and CA1 of rat hippocampal slices to identify possible excitatory circuits through which activation of nAChRs pr...

Pyramidal neurons in the CA1 region of the hippocampus are highly vulnerable to damage from hypoxia-ischemia, whereas neurons in the CA3 region and the dentate gyrus are more resistant. A similar pattern of vulnerability to loss of synaptic and membrane function occurs in the in vitro hippocampal slice preparation, suggesting that intrinsic factors are important in acute neuronal damage. Simult...

Conditioned medium prepared from slices of the rat hippocampal formation contains an agent that shares the following properties with nerve growth factor (NGF): it promotes neurite growth from embryonic sympathetic ganglia in vitro; and it is inhibited by affinity-purified antibody against mouse submaxillary gland 2.5 S NGF. The NGF-like growth-promoting activity is regionally distributed within...

The adult hippocampus consists of the dentate gyrus (DG) and the CA1, CA2 and CA3 regions and is essential for learning and memory functions. During embryonic development, hippocampal neurons are derived from hippocampal neuroepithelial cells and dentate granular progenitors. The molecular mechanisms that control hippocampal progenitor proliferation and differentiation are not well understood. ...

Microglia are evenly distributed throughout the brain parenchyma. They respond rapidly to a variety of alterations in the microenvironment of the brain and act as sensors for pathological events in the brain. In the present study, we investigated the age-dependent changes in the immunoreactivity and protein level of ionized calcium-binding adapter molecule 1 (Iba-1), a microglial marker, in the...

Recent studies have shown that place cells in the hippocampal CA1 region fire in a sequence sensitive manner. In this study we tested if hippocampal CA3 and CA1 regions can give rise to the sequence sensitivity. We used a two-layer CA3-CA1 hippocampal model that consisted of Hodgkin-Huxley style neuron models. Sequential input signals that mimicked signals projected from the entorhinal cortex g...