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Long term potentiation and synaptic plasticity

Video transcript

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 will just get bigger and bigger but what does happen is that the 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 strengths so 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 presynaptic neuron which is the neuron leading up to the synapse and we have a postsynaptic neuron which is the neuron immediately following the synapse when the presynaptic neuron is stimulated it releases neurotransmitters or special chemicals which then bind to receptors on the postsynaptic neuron opening channels to allow ions such as sodium and calcium to flow in now all neurons have a surrounding membrane and the interior has a different electrical charge than the exterior of the membrane and this difference in charges is called the neurons potential the number of ions that flow into the postsynaptic neuron effect that difference this is actually how we measure the strength of the synapse by how much the postsynaptic neurons potential changes as a result of presynaptic stimulation so what's really cool is that with repeated stimulation the same level of presynaptic stimulation converts into greater postsynaptic potential in other words after the presynaptic neuron gets a lot of practice firing and sending signals to a specific postsynaptic neuron it gets better at sending those signals and I'll end up getting better at opening the channels to allow more eye then 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 and this is thought to be the physiological mechanism by which learning occurs as synapses are strengthened and as they retain that strength we're able to more easily recall previous experiences