Name: synaptic strengthening in learning and memory
Uploaded: 2025-10-23T11:49:27.000Z
Duration: 1 min 35 s
Channel: JoVE

- [Instructor] La potenciación
a largo plazo, o LTP, es

un proceso de fortalecimiento
sináptico que se prolonga en

el tiempo

entre las conexiones neuronales
pre y post sinápticas.

En un mecanismo, cuando
las neuronas presinápticas

disparan y estimulan repetidamente
la célula postsináptica,

esta acción induce cambios en el tipo

y número de canales de iones
en la membrana post sináptica,

tales como una clase de
receptores de glutamato llamados

N-metil-D-asparato, o NMDA.

Los receptores NMDA son
generalmente inactivados

por iones de magnesio, sin
embargo, con una fuerte

despolarización

por estimulación repetida,
los iones de magnesio son

desplazados

permitiendo la entrada de iones de calcio.

Este flujo de calcio inicia
una cascada de señalización

que culmina en una segunda clase
de receptores de glutamato.

Alfa amino tres hidroxi
cinco metilo cuatro

ácido isoxazolpropiónico,
AMPA para abreviar,

insertando en la membrana.

En este caso, los iones más
positivos fluyen hacia la

neurona

haciendo una respuesta
postsináptica más fuerte

a la misma estimulación presináptica.

La LTP es esencial para el aprendizaje,

y es una manera de explicar
que la práctica del adagio hace

que sea perfecta,

ya que la respuesta recientemente
fortalecida puede durar

de minutos a semanas o más

si la estimulación presináptica persiste.

Nicoll, Roger A. "Una breve historia de la potenciación a largo plazo". Neurona 93, no. 2 (18 de enero de 2017): 281–90. [<a href="https://doi.org/10.1016/j.neuron.2016.12.015" target="__blank">Fuente</a>]

Bliss, T. V. P., G. L. Collingridge y R. G. M. Morris. "Plasticidad sináptica en la salud y la enfermedad: introducción y visión general". Philosophical Transactions of the Royal Society B: Biological Sciences 369, n.º 1633 (5 de enero de 2014). [<a href="https://doi.org/10.1098/rstb.2013.0129" target="__blank">Fuente</a>]

la potenciación a largo plazo

La potenciación a largo plazo, o LTP, es una de las formas en que la plasticidad sináptica,cambios en la fuerza de las sinapsis químicas, puede ocurrir en el cerebro. LTP es el proceso de fortalecimiento sináptico que ocurre con el tiempo entre las conexiones neuronales pre y postsinápticas. El fortalecimiento sináptico de la LTP actúa en oposición al debilitamiento sináptico de la depresión prolongada (LTD) y juntos son los principales mecanismos que subyacen al aprendizaje y la memoria. <h4>LTP de Hebbian</h4> La LTP puede ocurrir cuando las neuronas presinápticas activan y estimulan repetidamente la neurona postsináptica. Esto se llama LTP hebbiano, ya que se desprende del postulado de Donald Hebb de 1949 de que "las neuronas que se activan juntas se conectan entre sí". La estimulación repetida de las neuronas presinápticas induce cambios en el tipo y número de canales iónicos en la membrana postsináptica. En la LTP participan dos tipos de receptores postsinápticos del neurotransmisor excitador glutamato: 1) receptores de N-metil-D-aspartato o NMDA y 2) receptores de ácido α-amino-3-hidroxi-5-metil-4-isoxazolpropiónico o AMPA. Aunque los receptores NMDA se abren tras la unión del glutamato, sus poros suelen estar bloqueados por iones de magnesio que impiden que otros iones cargados positivamente entren en la neurona. Sin embargo, el glutamato liberado por las neuronas presinápticas puede unirse a los receptores AMPA postsinápticos, provocando una entrada de iones de sodio que da como resultado la despolarización de la membrana. Cuando la membrana postsináptica se despolariza por múltiples entradas presinápticas frecuentes, el ion magnesio que bloquea el poro del receptor NMDA se desplaza, permitiendo que los iones de sodio y calcio fluyan hacia la neurona. El aumento de la entrada de iones de calcio inicia una cascada de señalización que culmina con la inserción de más receptores AMPA en la membrana plasmática. Alternativamente, la cascada de señalización puede fosforilar los receptores de glutamato, permitiéndoles permanecer abiertos durante más tiempo y mejorar la conductancia de iones cargados positivamente hacia el interior de la célula. Como resultado, la misma estimulación presináptica ahora provocará una respuesta postsináptica más fuerte, dado que se activarán más receptores de glutamato y entrarán más iones cargados positivamente en la neurona postsináptica. La amplificación que se produce se conoce como fortalecimiento o potenciación sináptica. El dicho “la práctica hace la perfección” puede explicarse en parte mediante la LTP. Cuando se aprende una tarea nueva, se refuerzan nuevos circuitos neuronales mediante LTP. Después de cada iteración de práctica, la fuerza sináptica en los circuitos neuronales se fortalece y pronto la tarea se puede realizar de manera correcta y eficiente. Las conexiones recién fortalecidas pueden durar desde minutos hasta semanas o más si la estimulación presináptica persiste, lo que significa que cada vez que se realiza la tarea posterior se mantiene la LTP. <h4>LTP y enfermedad</h4> Cuando LTP funciona normalmente, podemos aprender y formar recuerdos con facilidad. Sin embargo, las anomalías en la LTP se han implicado en muchos trastornos neurológicos y cognitivos como la enfermedad de Alzheimer, el autismo, la adicción, la esquizofrenia y la esclerosis múltiple. Una mejor comprensión de los mecanismos detrás de la LTP podría eventualmente conducir a terapias.

La potenciación a largo plazo

La potenciación a largo plazo, o LTP, es una de las formas en que la plasticidad sináptica (cambios en la fuerza de las sinapsis químicas) puede ocurrir en el ...

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Nervous System

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KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

Long-term Potentiation

synaptic strengthening in learning and memory

Long-term potentiation, or LTP, is a form of synaptic strengthening in the brain. It changes the strength of chemical synapses over time between pre- and postsynaptic neurons. LTP works against long-term depression, or LTD, which weakens synapses. Together, LTP and LTD are major mechanisms behind learning and memory.

LTP can happen when a presynaptic neuron fires again and again and keeps stimulating a postsynaptic neuron. This is called Hebbian LTP, based on Donald Hebb’s idea that neurons that fire together wire together. Repeated stimulation changes the types and number of ion channels in the postsynaptic membrane. Two glutamate receptors are involved: NMDA receptors and AMPA receptors.

NMDA receptors open when glutamate binds, but magnesium ions usually block the pore. At the same time, glutamate can activate AMPA receptors on the postsynaptic cell. This causes sodium ions to enter and depolarize the membrane. When many presynaptic inputs arrive in quick succession, the magnesium block is removed from the NMDA receptor. Sodium and calcium ions then enter the neuron.

The calcium influx starts a signaling cascade inside the cell. This cascade leads to more AMPA receptors being inserted into the plasma membrane. It can also phosphorylate glutamate receptors, which helps them stay open longer and lets more positively charged ions enter the cell. The same presynaptic signal then creates a stronger postsynaptic response. This increase is called synaptic strengthening, or potentiation.

LTP also helps explain why practice makes perfect. When a new task is learned, new neural circuits are reinforced by LTP. With each round of practice, the synaptic strength in those circuits becomes stronger. Over time, the task can be performed more correctly and efficiently. These strengthened connections can last from minutes to weeks or longer if presynaptic stimulation continues, so later practice can maintain the LTP.

When LTP works normally, learning and memory are easier. Problems with LTP have been linked to Alzheimer’s disease, autism, addiction, schizophrenia, and multiple sclerosis. Understanding how LTP works may help guide future therapies for these neurological and cognitive disorders.

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long-term potentiation

Long-term potentiation, or LTP, is a form of synaptic strengthening in the brain. It changes the strength of chemical synapses over time between pre- and postsynaptic neurons. LTP works against long-term depression, or LTD, which weakens synapses. Together, LTP and LTD are major mechanisms behind learning and memory. LTP can happen when a presynaptic neuron fires again and again and keeps stimulating a postsynaptic neuron. This is called Hebbian LTP, based on Donald Hebb’s idea that neurons...

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Synaptic Strengthening in Learning and Memory

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