Articulatory Loop

Speaking pretty scientific terms, "Long-term Potentiation" is a good one. That's a process where a neuron becomes permanently (or at least semi-permanently) more sensitive to signaling. Usually, this happens with repeated stimulation, or very strong acute stimulation, which leads to an increase in receptors on the dendrite or, as recent studies to which I have no link show, even on the axon. Long-term potentiation may also involve alterations in the cell's resting potential (within the range of about -80 to -55 mV, of course, since above this you get activation), but that's a different part of the story.

There's tons of evidence linking LTP to learning and memory functions, which makes sense. How it all works, however, is a mess (like all of neuroscience, that's what makes it fun and interesting!). In today's issue of Science, a team of researchers have found that recycling endosomes seem to act as the 'storehouse' for receptors bound to and from the membrane. When they stimulated LTP, they found that these organelles do the legwork of upping (or, in the converse, reducing) the cell's receptor densities. But, surprisingly, they also saw increased recycling of other molecules as well! This is one of the fun things about science: the more you learn, the more mysteries you find!