title: Selective alterations of neurons and circuits related to early memory loss in Alzheimer's disease.
abstract: A progressive loss of episodic memory is a well-known clinical symptom that characterizes Alzheimer's disease (AD). The beginning of this loss of memory has been associated with the very early, pathological accumulation of tau and neuronal degeneration observed in the entorhinal cortex (EC). Tau-related pathology is thought to then spread progressively to the hippocampal formation and other brain areas as the disease progresses. The major cortical afferent source of the hippocampus and dentate gyrus is the EC through the perforant pathway. At least two main circuits participate in the connection between EC and the hippocampus; one originating in layer II and the other in layer III of the EC giving rise to the classical trisynaptic (ECII → dentate gyrus → CA3 → CA1) and monosynaptic (ECIII → CA1) circuits. Thus, the study of the early pathological changes in these circuits is of great interest. In this review, we will discuss mainly the alterations of the granule cell neurons of the dentate gyrus and the atrophy of CA1 pyramidal neurons that occur in AD in relation to the possible differential alterations of these two main circuits.
authors.affiliation: Consejo Superior de Investigaciones Cientificas-Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid Madrid, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Llorens-Martín
authors.affiliation: Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain ; Instituto Cajal, Consejo Superior de Investigaciones Cientificas Madrid, Spain.
authors.forename: Lidia
authors.initials: L
authors.lastname: Blazquez-Llorca
authors.affiliation: Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain ; Instituto Cajal, Consejo Superior de Investigaciones Cientificas Madrid, Spain ; Centro de Investigación en Red sobre Enfermedades Neurodegenerativas Madrid, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Benavides-Piccione
authors.affiliation: Departamento de Neuropatología y Banco de Tejidos, Fundación CIEN, Instituto de Salud Carlos III Madrid, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Rabano
authors.affiliation: Consejo Superior de Investigaciones Cientificas-Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid Madrid, Spain.
authors.forename: Felix
authors.initials: F
authors.lastname: Hernandez
authors.affiliation: Consejo Superior de Investigaciones Cientificas-Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid Madrid, Spain ; Centro de Investigación en Red sobre Enfermedades Neurodegenerativas Madrid, Spain.
authors.forename: Jesus
authors.initials: J
authors.lastname: Avila
authors.affiliation: Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain ; Instituto Cajal, Consejo Superior de Investigaciones Cientificas Madrid, Spain ; Centro de Investigación en Red sobre Enfermedades Neurodegenerativas Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: DeFelipe
keywords: amyloid beta pathology; cerebral cortex; dendritic spines; granule cells; hippocampal connections; neurogenesis; pyramidal cells; spread of tau