2-Minute Neuroscience: Long-Term Potentiation (LTP) Video Lecture | A-Z Guide to Neuroscience - Personal Learning

Welcome to 2 minute neuroscience, where I
explain neuroscience topics in 2 minutes or
less.
In this installment I will discuss long-term
potentiation, or LTP.
LTP is a process by which synaptic connections
between neurons become stronger with frequent
activation.
LTP is thought to be a way in which the brain
changes in response to experience, and thus
may be an mechanism underlying learning and
memory.
There are a number of ways in which LTP can
occur.
The best-known mechanism involves a glutamate
receptor known as the NMDA receptor.
In NMDA-receptor dependent LTP, glutamate
release first activates a subtype of glutamate
receptor known as the AMPA receptor.
NMDA receptors are found nearby these AMPA
receptors, but are not activated by low levels
of glutamate release because the ion channel
of an NMDA receptor is blocked by a magnesium
ion.
If frequent action potentials cause greater
stimulation of AMPA receptors, however, this
will cause the postsynaptic neuron to depolarize,
which eventually causes the voltage-dependent
magnesium blockage of the NMDA receptor to
be removed, allowing calcium ions to flow
in through the NMDA receptor.
This influx of calcium initiates cellular
mechanisms that cause more AMPA receptors
to be inserted into the neuron’s membrane.
The new AMPA receptors are also more responsive
to glutamate, and allow more positively charged
ions to enter the cell when activated.
Now, the postsynaptic cell is more sensitive
to glutamate because it has more receptors
to respond to it.
Additionally, there are thought to be signals
that travel back across the synapse to stimulate
greater levels of glutamate release.
All of this makes the synapse stronger and
more likely to be activated in the future.
This process is also associated with changes
in gene transcription in the neuron, which
can lead to the production of new receptors
or modifications to the structure of the cell.
These changes seem to be important for making
the increased responsiveness of LTP long-lasting.