Lesions restricted to the hippocampal formation and/or extended hippocampal system (hippocampal formation, fornix, mammillary bodies, and anterior thalamic nuclei) can disrupt conscious recollection in anterograde amnesia, while leaving familiarity-based memory relatively intact. Familiarity may be supported by extra-hippocampal medial temporal lobe (MTL) structures. Within-task dissociations i...

In the pilocarpine model of chronic limbic seizures, subpopulations of glutamic acid decarboxylase (GAD)-containing neurons within the hilus of the dentate gyrus and stratum oriens of the CA1 hippocampal region are vulnerable to seizure-induced damage. However, many gamma-aminobutyric acid (GABA) neurons remain in these and other regions of the hippocampal formation. To determine whether long-t...

The entorhinal cortex functions as the gateway to the hippocampal formation. However, its role in formation and consolidation of hippocampus-dependent memory remains relatively unexplored. In this issue of Neuron, Yasuda and Mayford report an elegant cell-type restricted inducible transgenic mouse overexpressing a mutant form of CaM kinase II selectively in superficial layers of medial entorhin...

For more than a decade, there has been extensive discussion about whether hippocampal sclerosis causes enhanced neuronal excitability as a prerequisite for seizure generation. The disorder known as Ammon’s horn sclerosis (AHS) is characterized by pronounced cell loss and gliosis in various regions of the hippocampal formation, leaving the subiculum generally intact (1, 2). Given the hypothesis ...

Myelin-associated proteins are involved in the formation and stabilization of myelin sheaths. In addition, they prevent axon regeneration and plasticity in the adult brain. Recent evidence suggests that the expression of certain myelin-associated proteins (e.g. Nogo-A) can be regulated by synaptic activity or by over-expression after neural lesions in brain syndromes such as temporal lobe epile...

The induction of long-term potentiation (LTP) in the hippocampal formation can be modulated by different behavioral states. However, few studies have addressed modulation of LTP during behavioral states in which the animal is likely acquiring new information. Here, we demonstrate that both the induction and the longevity of LTP in the dentate gyrus are enhanced when LTP is induced during the in...

Estrogen receptor-alpha (ERalpha), estrogen receptor-beta (ERbeta), and progestin receptor (PR) immunoreactivities are localized to extranuclear sites in the rat hippocampal formation. Because rats and mice respond differently to estradiol treatment at a cellular level, the present study examined the distribution of ovarian hormone receptors in the dorsal hippocampal formation of mice. For this...

Lobus limbicus is anatomical basis for explaining the temporal epilepsy because it not only includes the focus of infection of temporal lobe but also the frontal lobe, and with it we can explain many of the phenomenon's of the epilepsy (hallucinations, the change of the effects, and so on.). The goal of this assignment was to explore the asymmetry of hippocampal formation on the patients with c...

Tropomyosin-related kinase B receptor (TrkB) is a neurotrophin receptor important for the synaptic plasticity underlying hippocampal-dependent learning and memory. Because this receptor is widely expressed in hippocampal neurons, the precise location of TrkB activation is likely important for its specific actions. The goal of this study was to identify the precise sites of TrkB activation in th...

Regional cerebral blood flow (rCBF) was measured using positron emission tomography during eyeblink conditioning in young adults. Subjects were scanned in three experimental conditions: delay conditioning, in which binaural tones preceded air puffs to the right eye by 400 msec; pseudoconditioning, in which presentations of tone and air puff stimuli were not correlated in time; and fixation rest...