Long term potentiation and synaptic plasticity | Processing the Environment | MCAT | Khan Academy


How do you learn?
This is a tougher question than it seems. You might know that you
learn by studying, for example, but what changes occur in your brain
when you read a chapter for the first time or when you test yourself
on your knowledge? You probably realize that your brain
doesn’t just grow new cells to store your memories, otherwise our heads would
just get bigger and bigger. What does happen is that connections
between neurons strengthen. This is called long-term potentiation,
or LTP and it’s one example of synaptic plasticity, which is the ability
of synapses to change their strength. Let’s look at this process
in more detail. Neurons communicate using
electrochemical signals, that means a combination
of electricity and chemicals. When neurons communicate, they actually
don’t connect to each other directly, there’s a junction in between
called the synapse. So we have a pre-synaptic neuron, which is a neuron leading up
to the synapse, and we have a post-synaptic neuron, which is the neuron immediately
following the synapse. When the pre-synaptic neuron
is stimulated, it releases neurotransmitters,
or special chemicals which then bind to receptors
on the post-synaptic neuron, opening channels to allow ions such as sodium and calcium
to flow in. All neurons have a surrounding membrane and the interior has a different
electrical charge than the exterior of the membrane. This difference in charges
is called the neuron’s potential. The number of ions that flow into
the post-synaptic neuron affect that difference. This is how we measure
the strength of the synapse, by how much the post-synaptic
neuron’s potential changes as a result of pre-synaptic stimulation. With repeated stimulation, the same level
of pre-synaptic stimulation converts intogreater
post-synaptic potential. In other words, after the pre-synaptic
neuron gets a lot of practice firing and sending signals
to a specific post-synaptic neuron, it getsbetterat sending those signals, and will get better at opening the
channels to allow more ions in. When this happens, we say that
the synapse strength is increasing. When this increased strength lasts
for a long time, meaning anywhere from a few minutes
to many months, it’s called long term potentiation. This is thought to be the physiological
mechanism by which learning occurs. As synapses are strengthened
and they retain that strength, we’re able to more easily recall
previous experiences.

Comments 14

  • That is actually so fascinating and funky and awesome hehe

  • More like this please! 😀

    Suggested lectures, readings etc would be great to put in the description.

  • LTD also involves in learning

  • I love medicine.

  • This is not good. It´s very shallow, and explains more about action potential then LTP.

  • LTP in depth involved AMPA and NMDA receptors. AMPA receptors act as ionotropic receptors, which causes influx of Na+ after binding with glutamate. This depolarisation will causes the NMDA receptor to eject its Mg2+ ion that's blocking the channel. And it also binds with glutamate to allow Ca2+ influx. This influx would result in upregulation of these AMPA/NMDA receptors through secondary messengers (kinases). Thus, increasing the strength, frequency and excitability of the post-synaptic neurones.

  • THis is wrong. My teecher says that its because you need to grow more brain cells in you're neurons.

  • dam I liked the guys voice more. made me focus.

  • This is false. Long Term Potentiation is not the only way to learn. You didn't even mention Long Term Depression (LTD), which is the whole another side of learning and creating new memories.

  • I normally like your stuff but this is so basic.

  • It's really hard to find a concrete definition of plasticity and LTP, and this video does exactly that in a very clear way. Thank you!

  • I usually love your videos but this is not even close to what the appropriate LTP explanation…make a 12 minute videos and go through high and low frequency signals and types of LTP and NMDAR & AMPAR

  • thanks alot i've been reading for hours about this but i just couldn't understand it till i watched this video … u are amazing guys…keep going❤

  • the point is our neuron gets firing by the time you started to watch the video, so be grateful.

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