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Antequera Sánchez Carlos - One of the best experts on this subject based on the ideXlab platform.

  • Estudio de la conectividad funcional y efectiva entre el hipocampo y las cortezas entorrinal y prefrontal de rata a través de la evaluación de la sincronización del ritmo Theta de registros electrofisiológicos in vivo
    'Universitat Politecnica de Valencia', 2018
    Co-Authors: Antequera Sánchez Carlos
    Abstract:

    [ES] La comprensión del funcionamiento de nuestro cerebro es uno de los grandes retos planteados por la humanidad en el siglo XXI. Prueba de ello son los grandes proyectos impulsados por Europa (Human Brain) o Estados Unidos (BRAIN), así como la multitud de estudios que surgen cada día describiendo el comportamiento de regiones concretas, bajo ciertas restricciones. Siguiendo con las investigaciones sobre plasticidad neuronal realizadas en colaboración con el Instituto de Neurociencias de Alicante, se pretende estudiar la actividad eléctrica en el hipocampo de la rata. Esta estructura cerebral está fuertemente vinculada a la función de la memoria del ser humano y se ha demostrado su importante participación en la memoria espacial en roedores. El objetivo de este trabajo es el estudio de la sincronización entre el hipocampo y las cortezas entorrinal y prefrontal, principales estructuras cerebrales de entrada y salida al circuito del hipocampo. Ello se llevará a cabo a través de la medición y evaluación de los desfases entre componentes independientes, obtenidos a partir de señales electrofisiológicas in vivo de varios sujetos anestesiados. Además, se estudiará la evolución de este desfase en el tiempo y su variación con respecto a parámetros de interés de nuestras señales. Las señales a analizar son potenciales de campo local o LFPs (del ingés, local field potential), las cuales representan la actividad promedio del grupo de neuronas situadas alrededor de nuestro electrodo, cuyas contribuciones a la señal final dependen de las distancias a este. Estas señales pueden ser descompuestas en varios ritmos, como el ritmo gamma (30-100 Hz) o el Theta (4-8 Hz). Se cree que el primero corresponde a procesos locales, al presentar una mayor frecuencia, y el segundo corresponde a comunicación entre regiones alejadas mediante la sincronización entre ellas, debido a su menor frecuencia y su mayor amplitud, factores que facilitan esta sincronización. El ritmo Theta en el hipocampo ha sido objeto de investigación durante décadas el siglo pasado, en búsqueda de su relación con alguna función o comportamiento. En el presente trabajo se pretende evaluar la sincronización en Theta dentro de este circuito (entorrinal-hipocampo-prefrontal), caracterizando su comportamiento basal, sus implicaciones en las características de la señal (por ejemplo, potencia en Theta y gamma del LFP) y cómo cambia en distintas condiciones.[EN] One of the 21st century main objectives is the comprehension of how our brain works. Projects like "Human Brain", supported by Europe, or "BRAIN", supported by USA, and also many papers published every day explaining the behavior of some region under particular restrictions are proof of that. Following latest studies about neuronal plasticity carried out in collaboration with the Neuroscience Institute of Alicante, rat Hippocampus electrical activity will be studied. This structure is highly related to memory function of human being and its important role in spatial memory in rodents has been also proved. The main purpose of this work is to study the synchronization between Hippocampus, entorhinal cortex and prefrontal cortex. Both are principal brain structures of input and output in Hippocampus circuit. That is going to be carried out through the measurement and assessment of temporal delays between independent components, obtained from electrophysiological in vivo records from several asleep subjects. Moreover, we are going to study temporal evolution of that delay and its variation in relation to other signals parameters. The signals that we are going to assess are local field potentials (LFPs), which represent the average activity of groups of neurons placed around each electrode. Their contributions to the final signal depend on the distance between each neuron and the electrode. These signals could be split in many Rhythms like gamma Rhythm (30-100 Hz) or Theta Rhythm (4-8 Hz). It is thought that the first one is related to local processes due to its higher frequency, and the second one is related to communication between far regions by synchronization, due to its lower frequency and higher amplitude, factors that make the synchronization easier. Last century, many researchers has been focused on Hippocampus Theta Rhythm, searching for its relationship with any function or behavior. The aim of this work is to assess the synchronization of Theta Rhythm inside this memory circuit (entorhinal-Hippocampus-prefrontal), describing its basal behavior, how it affects signal's features.Antequera Sánchez, C. (2018). Estudio de la conectividad funcional y efectiva entre el hipocampo y las cortezas entorrinal y prefrontal de rata a través de la evaluación de la sincronización del ritmo Theta de registros electrofisiológicos in vivo. http://hdl.handle.net/10251/106486TFG

Sylvain Williams - One of the best experts on this subject based on the ideXlab platform.

  • Theta Rhythm in Hippocampus and cognition
    2020
    Co-Authors: Benedicte Amilhon, Guillaume Ducharme, Jesse Jackson, Romain Goutagny, Sylvain Williams
    Abstract:

    Theta Rhythm is a large 4–12 Hz oscillatory activity that is predominant during wake and REM (rapid eye movement) sleep in the Hippocampus. Theta Rhythm is generated by the interplay between neurons from the medial septum and entorhinal cortex, with local oscillators within the Hippocampus. These intrinsic hippocampal oscillators arise from the interaction between pyramidal cells and specific subtypes of interneurons. Theta contributes to the formation of place cell assemblies important for memory and navigation. In addition, Theta in Hippocampus can control spiking and computations in other brain regions such as the prefrontal cortex, the amygdala, and striatum, and contribute to different cognitive tasks such as working memory, fear conditioning, motivation, and reward. As such, Theta Rhythm in Hippocampus plays a critical role in providing spatial and contextual information locally and throughout the brain.

Di Prisco - One of the best experts on this subject based on the ideXlab platform.

  • BEHAVIORAL AND COGNITIVE NEUROSCIENCE REVIEWS Vertes et al. / Theta Rhythm OF THE Hippocampus Theta Rhythm of the Hippocampus: Subcortical Control and Functional Significance
    2016
    Co-Authors: Robert P Vertes, Walter B Hoover, Gonzalo Viana, Di Prisco
    Abstract:

    The Theta Rhythm is the largest extracellular synchronous signal that can be recorded from the mammalian brain and has been strongly implicated in mnemonic processes of the Hippocampus. We describe (a) ascending brain stem–forebrain systems involved in controlling Theta and nonTheta (desynchronization) states of the hippocampal electroencephalogram; (b) Theta rhyth-mically discharging cells in several structures of Papez’s circuit and their possible functional significance, specifically with respect to head direction cells in this same circuit; and (c) the role of nucleus reuniens of the thalamus as a major interface between the medial prefrontal cortex and Hippocampus and as a promi-nent source of afferent limbic information to the Hippocampus. We suggest that the Hippocampus receives two main types of input: Theta Rhythm from ascending brain stem–diencephalo-septal systems and information bearing mainly fro

Benedicte Amilhon - One of the best experts on this subject based on the ideXlab platform.

  • Theta Rhythm in Hippocampus and cognition
    2020
    Co-Authors: Benedicte Amilhon, Guillaume Ducharme, Jesse Jackson, Romain Goutagny, Sylvain Williams
    Abstract:

    Theta Rhythm is a large 4–12 Hz oscillatory activity that is predominant during wake and REM (rapid eye movement) sleep in the Hippocampus. Theta Rhythm is generated by the interplay between neurons from the medial septum and entorhinal cortex, with local oscillators within the Hippocampus. These intrinsic hippocampal oscillators arise from the interaction between pyramidal cells and specific subtypes of interneurons. Theta contributes to the formation of place cell assemblies important for memory and navigation. In addition, Theta in Hippocampus can control spiking and computations in other brain regions such as the prefrontal cortex, the amygdala, and striatum, and contribute to different cognitive tasks such as working memory, fear conditioning, motivation, and reward. As such, Theta Rhythm in Hippocampus plays a critical role in providing spatial and contextual information locally and throughout the brain.

Robert P Vertes - One of the best experts on this subject based on the ideXlab platform.

  • BEHAVIORAL AND COGNITIVE NEUROSCIENCE REVIEWS Vertes et al. / Theta Rhythm OF THE Hippocampus Theta Rhythm of the Hippocampus: Subcortical Control and Functional Significance
    2016
    Co-Authors: Robert P Vertes, Walter B Hoover, Gonzalo Viana, Di Prisco
    Abstract:

    The Theta Rhythm is the largest extracellular synchronous signal that can be recorded from the mammalian brain and has been strongly implicated in mnemonic processes of the Hippocampus. We describe (a) ascending brain stem–forebrain systems involved in controlling Theta and nonTheta (desynchronization) states of the hippocampal electroencephalogram; (b) Theta rhyth-mically discharging cells in several structures of Papez’s circuit and their possible functional significance, specifically with respect to head direction cells in this same circuit; and (c) the role of nucleus reuniens of the thalamus as a major interface between the medial prefrontal cortex and Hippocampus and as a promi-nent source of afferent limbic information to the Hippocampus. We suggest that the Hippocampus receives two main types of input: Theta Rhythm from ascending brain stem–diencephalo-septal systems and information bearing mainly fro