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...

In the present study, the effects of intra-dorsal hippocampal (intra-CA1) injections of nitric oxide (NO) agents on muscimol state-dependent memory were examined in mice. A single-trial step-down passive avoidance task was used for the assessment of memory retrieval in adult male NMRI mice. Post-training intra-CA1 administration of a GABAA receptor agonist, muscimol (0.05 and 0.1 μg/mouse) dose...

KEY POINTS The hippocampal CA1 region is highly vulnerable to ischaemic stroke. Two forms of AMPA receptor (AMPAR) plasticity - an anoxic form of long-term potentiation and a delayed increase in Ca(2+) -permeable (CP) AMPARs - contribute to this susceptibility by increasing excitotoxicity. In CA1, the acid-sensing ion channel 1a (ASIC1a) is known to facilitate LTP and contribute to ischaemic ac...

We describe an implantable patch sensor for monitoring L-glutamate in hippocampal slices in submerged and interface preparations. This patch sensor is prepared by excising the cell membrane in the CA3 region of a hippocampal slice in a submerged preparation, and then implanted in the target neuronal region (CA1) of mouse hippocampal slices. The lifetime of the sensor was 3-8 min for the interfa...

Long-term potentiation and long-term depression (LTD) of synaptic efficacy, two major forms of synaptic plasticity, are believed to underlie learning processes and memory storage. We have recently shown that acute stress, through corticosterone release and stimulation of glucocorticoid receptors (GRs), facilitates the LTD elicited by the group 1 metabotropic glutamate receptor (mGluR) agonist (...

Introduction: Gap junctions are specialized cell–cell contacts between eukaryotic cells through which they communicate. This type of communication has the potential to modulate memory process. We evaluated the effects of the gating of the hippocampal CA1 area gap junction channels on memory consolidation, using passive avoidance task. Materials and Methods: 72 adult male Wistar rats were distri...

The learning mechanism in the hippocampus has almost universally been assumed to be Hebbian in nature, where individual neurons in an engram join together with synaptic weight increases to support facilitated recall of memories later. However, it is also widely known that Hebbian learning mechanisms impose significant capacity constraints, and are generally less computationally powerful than le...

Several types of learning and memory processes are regulated by the hippocampus which is an important subcortical structure in the mammalians' brain. Previous investigations have shown that different receptor systems in the CA1 region of hippocampus are involved in learning and memory functions. Investigating the possible influence of dorsal hippocampal GABA-A receptors on histamine-induced spa...

The hippocampal theta rhythm is a prominent oscillation in the field potential observed throughout the hippocampus as a rat investigates stimuli in the environment. A recent computational model [Hasselmo, M. E., Bodelon, C., & Wyble, B. P. (2002a). A proposed function for hippocampal theta rhythm: separate phases of encoding and retrieval enhance reversal of prior learning. Neural Computation, ...

Woodhall, Gavin, Christine E. Gee, Richard Robitaille, and (McBain and Dingledine 1993; Morin et al. 1996; Sah et al. Jean-Claude Lacaille. Membrane potential and intracellular Ca 1990). Interneurons of the hippocampal CA1 region receive oscillations activated by mGluRs in hippocampal stratum oriens/ major excitatory inputs from CA3 and/or CA1 pyramidal alveus interneurons. J. Neurophysiol. 81:...