The anatomical connectivity and intrinsic properties of entorhinal cortical neurons give rise to ordered patterns of ensemble activity. How entorhinal ensembles form, interact, and accomplish emergent processes such as memory formation is not well-understood. We lack sufficient understanding of how neuronal ensembles in general can function transiently and distinctively from other neuronal ense...

The lateral entorhinal cortex receives strong inputs from midbrain dopamine neurons that can modulate its sensory and mnemonic function. We have previously demonstrated that 1 µM dopamine facilitates synaptic transmission in layer II entorhinal cortex cells via activation of D1-like receptors, increased cAMP-PKA activity, and a resulting enhancement of AMPA-receptor mediated currents. The prese...

The extracellularly recorded theta oscillation reflects a dynamic interaction of various synaptic and cellular mechanisms. Because the spatially overlapping dipoles responsible for the generation of theta field oscillation may represent different mechanisms, their separation might provide clues with regard to their origin and significance. We used a novel approach, partial coherence analysis, t...

Psychiatric illnesses, particularly schizophrenia, are associated with disrupted markers for interneuronal function and interneuron-mediated brain rhythms such as gamma frequency oscillations. Here we investigate a possible link between these two observations in the entorhinal cortex and hippocampus by using a genetic and an acute model of psychiatric illness. Lysophosphatidic acid 1 receptor-d...

INTRODUCTION An animal model of late-onset Alzheimer's disease is needed to research what causes degeneration in the absence of dominant genetic insults and why the association cortex is particularly vulnerable to degeneration. METHODS We studied the progression of tau and amyloid cortical pathology in the aging rhesus macaque using immunoelectron microscopy and biochemical assays. RESULTS ...

Small electrolytic lesions were placed in the basal and lateral amygdaloid nuclei of the dog and the distribution of degenerating fibers was studied with Nauta and Fink-Heimer modifications of the impregnation methods. Degenerating axons were followed into the hippocampal region and entorhinal cortex as well as insular and temporal cortices. The present results suggest that: (i) The hippocampal...

A total of 182 young adult male Wistar rats were bilaterally implanted with cannulae into the CA1 region of the dorsal hippocampus and into the amygdaloid nucleus, the entorhinal cortex, and the posterior parietal cortex. After recovery, the animals were trained in a step-down inhibitory avoidance task. At various times after training (0, 30, 60 or 90 min) the animals received a 0.5-microliter ...

Commentary The entorhinal cortex stands out among the myriad of mysterious and elegant brain structures as a relay station between the neocortical parahippocampus and the more primal memory-encoding, seizure-producing hippocampus. It seems to have not six neocortical layers or three archicortical layers, but arguably five to eight layers with one atrophied layer (layer IV, the lamina dessicans)...