The hippocampus plays a critical role in the memory for sequences of events, a defining feature of episodic memory. To shed light on the fundamental mechanisms supporting this capacity, we recently recorded neural activity in CA1 as rats performed a nonspatial odor sequence memory task. Our main finding was that, while the animals' location and behavior remained constant, a proportion of CA1 ne...

Previous studies have revealed a loss of neurons in layer III of the entorhinal cortex (EC) in patients with temporal lobe epilepsy. These neurons project to the hippocampus and may activate inhibitory interneurons, so that their loss could disrupt inhibitory function in the hippocampus. The present study evaluates this hypothesis in a rat model in which layer III neurons were selectively destr...

Hippocampus (HPC) receives dopaminergic (DA) projections from the ventral tegmental area (VTA) and substantia nigra. These inputs appear to provide a modulatory signal that influences HPC dependent behaviors and place fields. We examined how efferent projections from VTA to HPC influence spatial working memory and place fields when the reward context changes. CA1 and CA3 process environmental c...

Action potentials are the end product of synaptic integration, a process influenced by resting and active neuronal membrane properties. Diversity in these properties contributes to specialized mechanisms of synaptic integration and action potential firing, which are likely to be of functional significance within neural circuits. In the hippocampus, the majority of subicular pyramidal neurons fi...

The differentiation between the CA3 and CA1 fields of the mammalian hippocampus is one of the salient traits that set it apart from the organization of the homologue medial wall in reptiles and birds. CA3 is widely thought to function as an autoassociator, but what do we need CA1 for? Based on evidence for a specific role of CA1 in temporal processing, I have explored the hypothesis that the di...

epilepsy is one of the common disorders in human community. clinical observations have shown that epileptic patients have often difficulty in learning and memory. kindling is a laboratory model for studying epilepsy and its complications. this experiment was designed to study the effect of chemical kindling on schaffer collateral-ca1 pyramidal cell synaptic transmission using pentylenetetrazole...

the plethora of studies indicated that there is a cross talk relationship between harmaline and serotonergic (5-ht) system on cognitive and non-cognitive behaviors. thus, the purpose of this study is assessment the effects of ca1 5-ht4 receptor on memory acquisition deficit induced by harmaline. harmaline was injected peritoneally, while 5-ht4 receptor agonist (rs67333) and antagonist (rs23597-...

Background & Aims: Change in visual experience impairs circadian rhythms. In this study, The effects of visual deprivation during critical period of brain development and melatonin intake on synaptic plasticity of hippocampal CA1 neurons were evaluated. Methods: This experimental study was done on male rats kept in standard 12 hour light/dark condition (L...

The hippocampal CA1 region receives cortical information via two main inputs: directly via the perforant (temporoammonic) path (pp-CA1 synapse) and indirectly via the tri-synaptic pathway. Although synaptic plasticity has been reported at the pp-CA1 synapse of freely behaving animals, the mechanisms underlying this phenomenon have not been investigated. Here, we explored whether long-term poten...