If we want to compare the neurotransmitters released into a synapse to keys that are inserted into locks, we can say that it is mainly the locks (proteins) that will be chemically modified so that they become more sensitive and hence open more readily.
Moreover, if the synapse is stimulated for long enough, new “locks” may also be manufactured by the genes and inserted into the neural membrane alongside the existing ones. Completely new connections may even be built that will form the permanent record of our oldest memories.
The hippocampus is a brain structure that is deeply involved in
long-term memory, even though it appears to be only a temporary
transit point for memories.
Nevertheless, the neurons of the hippocampus display remarkable
plasticity. Some of them, when they receive a number of nerve
impulses over a short period, will strengthen the synaptic connections
through which these impulses were received. This increase in
the efficiency of these synapses can last hours, days, or even
The term “long-term potentiation” is
used to describe these molecular changes, which are probably the
basis for much long-term learning.
The process that results in long-term potentiation is presented
briefly in the following diagram. (Click on numbers 2, 3, and 4
to see the corresponding steps in this process.)