The perforant path constitutes the primary projection system relaying information from the neocortex to the hippocampal formation. Long-term synaptic potentiation (LTP) in the perforant path projections to the dentate gyrus is well characterized. However, surprisingly few studies have addressed the mechanisms underlying LTP induction in the direct perforant path projections to the hippocampus. ...

The perforant path forms a monosynaptic connection between the cells of layer II of the entorhinal cortex and the pyramidal cells in hippocampal area CA3. Although this projection is prominent anatomically, very little is known about the physiological properties of this input. The distal location of these synapses suggests that somatically recorded perforant-path excitatory postsynaptic potenti...

Glutamatergic activation of the locus coeruleus results in long-term potentiation of dentate gyrus perforant path-evoked population spike amplitude, when paired with perforant path stimulation (.25 Hz). In vitro evidence, however, suggests that this β-adrenoceptor-mediated effect can also occur in the absence of perforant path activity. The present study seeks to determine whether pairing of pe...

introduction: previous studies have been shown that low frequency stimulation (lfs) has an inhibitory effect on kindling acquisition. however, the mechanism of this effect has not been completely determined. in the present study, the effect of lfs of the perforant path on seizures induced by rapid perforant path kindling was investigated. methods: animals were kindled by electrical stimulation ...

Introduction: Previous studies have been shown that low frequency stimulation (LFS) has an inhibitory effect on kindling acquisition. However, the mechanism of this effect has not been completely determined. In the present study, the effect of LFS of the perforant path on seizures induced by rapid perforant path kindling was investigated. Methods: Animals were kindled by electrical stimulatio...

The perforant path provides the main excitatory input into the hippocampus and has been proposed to play a critical role in the generation of temporal lobe seizures. It has been hypothesized that changes in glutamatergic transmission in this pathway promote the epileptogenic process and seizure generation. We therefore asked whether epileptogenesis is associated with enhanced glutamatergic tran...

We examined the characteristics of heterosynaptic long-term depression (LTD) and depotentiation of previously established long-term potentiation (LTP) in the medial and lateral entorhinal afferents to the dentate gyrus in the awake rat. Rats were prepared for chronic recording of dentate gyrus evoked potentials to activation of the medial and lateral perforant paths. This study in awake rats co...

The entorhinal cortex provides both direct and indirect inputs to hippocampal CA1 neurons through the perforant path and Schaffer collateral synapses, respectively. Using both two-photon imaging of synaptic vesicle cycling and electrophysiological recordings, we found that the efficacy of transmitter release at perforant path synapses is lower than at Schaffer collateral inputs. This difference...

A selective serotonin reuptake inhibitor is the most commonly prescribed antidepressant for the treatment of major depression. However, the mechanisms underlying the actions of selective serotonin reuptake inhibitors are not fully understood. In the dentate gyrus, chronic fluoxetine treatment induces increased excitability of mature granule cells (GCs) as well as neurogenesis. The major input t...

introduction: application of low-frequency stimulation (lfs) is a new method for treatment of drug resistant epileptic patients. previous studies demonstrated that activation of receptors coupled to gi proteins is one of the mechanisms of the anticonvulsant effect of lfs. thus, in this study, alterations in the expression of rgs4 and rgs10 proteins, as negative regulators of gi proteins, were i...