Electrophysiological and anatomical techniques were used to determine the role, in the hippocampal circuitry, of local circuit neurons located at the oriens/alveus border (O/A interneurons). Intracellular recording from these cells showed that their response characteristics were clearly nonpyramidal: high input resistance, short membrane time constant, short-duration action potential, pronounce...

Ischemia/Reperfusion (I/R)-induced cerebral injury has been reported as a leading cause of deathand long-term disabilities. Hippocampus is an area which is more sensitive to be affected by I/Rand hypoxic conditions. Coenzyme Q10 is a strong antioxidant which plays a role in membranestabilization. This study aims to investigate the possible role of CoQ10 in ameliorating thehistomorphological cha...

Animal studies have shown that prenatal stress is able to induce long-lasting neurobiological and behavioral alterations in adult offspring. In spite of the facts that hippocampus is sensitive to early developmental influences and its known functional importance in learning and memory, few data are available on the effect of prenatal stress on the structure of hippocampus. Therefore, this study...

Following prolonged stimulation of the perforant path input to the dentate gyrus, long-lasting changes occur in the synaptic responses and cell properties of cells in the fascia dentata. The present study describes the effects of sustained stimulation on the major population of cells innervated by the dentate granule cells: are CA3 pyramidal cells of hippocampus. In 46% of slices from rat, sust...

Chronic exposure to lead (Pb) affects neural functions in central nervous system (CNS) particularly the learning and memory. On the other hand, alteration of calcium level in the CNS results in activation of NOS. It has been shown that lead enters the neurons through calcium channels and displaces Ca2+ from calcium binding proteins such as calmodulin and troponin C thereby affecting calcium-med...

In the hippocampus, a CA3 pyramidal cell forms excitatory synapses with thousands of other pyramidal cells and inhibitory interneurons. By using sequential paired recordings from three connected cells, we show that the presynaptic properties of CA3 pyramidal cell terminals, belonging to the same axon, differ according to the type of target cell. Activation of presynaptic group III metabotropic ...

We examined whether excitation and inhibition are balanced in hippocampal cortical networks. Extracellular field and single-unit activity were recorded by multiple tetrodes and multisite silicon probes to reveal the timing of the activity of hippocampal CA1 pyramidal cells and classes of interneurons during theta waves and sharp wave burst (SPW)-associated field ripples. The somatic and dendrit...

GABAergic interneurons in the hippocampus express high levels of alpha7 nicotinic acetylcholine receptors, but because of the diverse roles played by hippocampal interneurons, the impact of activation of these receptors on hippocampal output neurons (i.e., CA1 pyramidal cells) is unclear. Activation of hippocampal interneurons could directly inhibit pyramidal neuron activity but could also prod...

Five pyramidal cells from the posteromedial barrel subfield of mouse SmI cortex were labeled by Golgi impregnation and then gold-toned and de-impregnated (Fairen, Peters & Saldanha, 1977). Subsequently, 40 to 70 pm-long segments of their apical dendrites occurring in layer IV were graphically reconstructed from serial thin sections to determine the distribution of their synapses. Thalamocortica...

The behaviour-contingent rhythmic synchronization of neuronal activity is reported by local field potential oscillations in the theta, gamma and sharp wave-related ripple (SWR) frequency ranges. In the hippocampus, pyramidal cell assemblies representing temporal sequences are coordinated by GABAergic interneurons selectively innervating specific postsynaptic domains, and discharging phase locke...