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

【讲师】长时程增强，简称LTP， 是一种长期出现在突触前神经元和 突触后神经元之间的一种突触增强过程。
 有一种原理称，若突触前神经元 反复发出并刺激突触后细胞， 那么，该活动就会导致突触后膜中的 离子通道的类型和数量发生改变， 例如一类名为N-甲基-D-天门冬胺酸或NMDA的 谷氨酸受体。
 NMDA受体通常会被镁离子灭活， 然而，通过反复刺激 产生的强烈去极化，会使镁离子被取代， 从而允许钙离子进入。
 这种钙流入会引发信号级联放大， 从而使第二类谷氨酸受体达到顶点。
 α-氨基-3-羟基-5-甲基-4 异恶唑-丙酸受体，简称AMPA， 插入突触后膜。
 在这种情况下，更多的阳离子流入神经元， 对同一突触前刺激产生 更强烈的突触后响应。
 LTP是学习能力的要素， 同时也应验了一句老话，熟能生巧， 因为重新加强的响应可以持续 数分钟到数周，或更久， 前提是突触前刺激一直持续。

Nicoll， Roger A. "长期增强简史"。神经元 93，第 2 期（2017 年 1 月 18 日）:281-90。[<a href="https://doi.org/10.1016/j.neuron.2016.12.015" target="__blank">来源</a>]

Bliss， T. V. P.， GL Collingridge， 和 R. G. M. Morris。"健康和疾病中的突触可塑性:简介和概述。"皇家学会哲学汇刊 B:生物科学 369，第 1633 期（2014 年 1 月 5 日）。[<a href="https://doi.org/10.1098/rstb.2013.0129" target="__blank">来源</a>]

增强效应

长期增强作用(Long-term potentiation，LTP)是突触可塑性(化学突触强度的变化)在大脑中发生的一种方式。LTP是突触加强的过程，发生在突触前和突触后神经元连接之间。LTP的突触增强作用与长期抑郁(LTD)的突触减弱相反，是构成学习和记忆基础的主要机制。
<h4>赫布长时程增强作用（Hebbian LTP）</h4>
 
 突触前神经元反复激发和刺激突触后神经元可发生LTP。这被称为赫布长时程增强作用（Hebbian LTP），因为它来源于唐纳德·赫布（Donald Hebb）在1949年的假设，即“一起燃烧的神经元连接在一起”。突触前神经元的反复刺激导致突触后膜离子通道的类型和数量发生变化。
 
 兴奋性神经递质谷氨酸的两种突触后受体与LTP有关：1）N-甲基-D-天冬氨酸或NMDA受体和2）和α-氨基-3-羟基-5-甲基-4-异恶唑啉丙酸或AMPA受体。虽然NMDA受体在谷氨酸结合时开放，但其孔通常被镁离子堵塞，阻止其它带正电的离子进入神经元。然而，突触前神经元释放的谷氨酸能与突触后AMPA受体结合，引起钠离子的涌入，导致膜去极化。当突触后膜被多次频繁的突触前输入去极化时，阻断NMDA受体孔的镁离子移位，使钠和钙离子流入神经元。
 
 钙离子内流的增加随后引发一个信号级联，最终导致更多的AMPA受体被插入到质膜中。或者，信号级联可能磷酸化谷氨酸受体，使其能够长时间保持开放，并增强正电荷离子进入细胞的电导。因此，同样的突触前刺激现在将引起更强的突触后反应，因为更多的谷氨酸受体将被激活，更多的正电荷离子将进入突触后神经元。这种放大作用被称为突触增强或增强。
 
 “熟能生巧”这句格言可以部分地用LTP来解释。当一个新的任务被学习时，新的神经回路被LTP强化。每次反复练习后，神经回路中的突触强度会增强，很快就能正确有效地完成任务。如果突触前刺激持续存在，新加强的连接可以持续几分钟到几周或更长时间，这意味着每次任务执行后，LTP都会保持。
 
<h4> LTP与疾病</h4>
 
 当LTP功能正常时，我们可以轻松地学习和形成记忆。然而，LTP的异常与许多神经和认知障碍有关，如阿尔茨海默病、自闭症、成瘾、精神分裂症和多发性硬化症。更好地理解LTP背后的机制最终可能导致治疗。

长时程增强作用（LTP）是突触可塑性——即化学突触传递效能发生改变——在...中发生的方式之一

Education

教育

JoVE Core

Biology

生物学

Human Biology

人类生物学

Nervous System

神经系统

KEY TERMS AND CONCEPTS

关键术语与概念

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.

Synaptic Strengthening in Learning and Memory

synaptic-strengthening-in-learning-and-memory

what is a nervous system?

Nervous System Parts and Control

The nervous system is a network of specialized cells that keeps the body working and helps it respond to the world around it. It controls essential functions such as heart rate and breathing. It also supports movement that helps an organism escape danger. In vertebrates, the nervous system has two major parts: the central nervous system, or CNS, and the peripheral nervous system, or PNS. The CNS includes the brain, spinal cord, and retina, which is the sensory tissue of the visual system. The...

the parasympathetic nervous system

Rest and Digest: Parasympathetic Control

The parasympathetic nervous system helps the body stay calm and return to a rested state. It is one of the two major divisions of the autonomic nervous system, which controls many unconscious functions such as heart rate and digestion. Its neurons are found in the brain and the peripheral nervous system, and they send axons to muscles, organs, and glands. This system is often called the “rest and digest” system because it supports body processes that restore homeostasis. It is most active...

the sympathetic nervous system

Sympathetic Stress Response and Body Changes

The sympathetic nervous system helps the body respond to stress and danger. It is one of the two main divisions of the autonomic nervous system. When it turns on, it prepares the body for action and puts lower-priority functions, such as digestion, on hold. This response is often called the fight-or-flight system. A surprise exam can trigger it, and students may notice a tight stomach, a dry mouth, and a fast heartbeat. In a real threat, the system shifts blood away from the digestive system...

the blood-brain barrier

How the Blood-Brain Barrier Works

The blood-brain barrier is a specialized system of blood vessels that helps control what enters the brain. It delivers nutrients from the blood while tightly regulating ions, molecules, pathogens, and other substances. This semipermeable barrier protects the brain and also makes it harder to deliver some therapies. The blood-brain barrier includes several cellular parts, especially endothelial cells and astrocytes. These cells share a common basement membrane and regulate movement between the...

neuron structure

How Neurons Send Signals

Neurons send signals through a clear set of structures that let them receive, process, and pass on information. They are the main cells of the nervous system and use electrochemical signals to communicate. Neurons also talk to other cells through neurotransmitters at junctions called synapses. Most neurons share three main parts: a cell body, also called the soma, dendrites, and an axon. The soma holds the nucleus and other organelles needed for cell function. Dendrites usually receive...

glial cells

Glial Cells and Nervous System Support

Glial cells support the nervous system and work alongside neurons. They are one of the two main cell types in the nervous system. Unlike neurons, glia do not send electrical signals, but they help with nearly every other part of nervous system function. In humans, glial cells are about as numerous as neurons in the brain. In the central nervous system, glia include astrocytes, oligodendrocytes, microglia, and ependymal cells. Astrocytes are the most common glial cells. They form organized,...

action potentials

How Nerve Signals Travel in Axons

Neurons send signals through action potentials, the rapid electrical changes that move along the axon. These signals lead to neurotransmitter release at axon terminals, which passes information through the nervous system. An action potential is an all-or-none change in membrane potential, the voltage across a cell membrane. A neuron usually has a resting membrane potential of about -70 millivolts. When it receives signals from neurotransmitters or sensory input, the membrane can become more...

the resting membrane potential

How Neurons Keep a Negative Resting Charge

Neurons keep a negative resting charge across their membrane. This electrical difference, called the membrane potential, comes from how ions move and how the membrane lets them pass. In a resting neuron, the inside is typically around -70 millivolts and is more negative than the outside, so the cell is polarized. Two main factors create this resting state. First, the membrane is selectively permeable, which means most ions and molecules cannot cross the lipid bilayer without help from ion...

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...

long-term depression

Synaptic Pruning in Long-term Depression

Long-term depression, or LTD, is a form of synaptic plasticity that weakens chemical synapses over time. It acts between presynaptic and postsynaptic neurons. LTD works in opposition to long-term potentiation, or LTP, which strengthens synapses. Together, LTD and LTP are two of the main mechanisms behind learning and memory. LTD helps the brain avoid staying locked in a fully strengthened state. If synapses were always maximally strengthened, the brain would become less efficient and it would...

the synapse

How Neurons Signal at Synapses

Neurons communicate through synapses, the points where two neurons meet to pass on signals. At a synapse, the sending neuron is the presynaptic cell, and the receiving neuron is the postsynaptic cell. Most neurons can serve in both roles because they send and receive information. Electrical synapses move signals directly between cells. The presynaptic and postsynaptic cells are linked by gap junctions, which are proteins that physically connect them. This type of synapse can pass electrical...

key terms and concepts

Explore how long-term potentiation strengthens synapses, supports learning and memory, and is linked to disorders such as Alzheimer’s disease and autism.

Synaptic Strengthening in Learning and Memory | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

JoVE Core系列通过300多节动画视频课简明易懂地讲解生物学中的关键概念，以及150余段视频展示科学家在现代实验室开展实际研究实验，让生物学变得平易近人。

myJoVE Corporation

Synaptic Strengthening in Learning and Memory

Description

Transcript

Tags