Nerve endings can make rapid and permanent changes to their structure given the correct signals. Properly speaking nerve endings are found only in the periphery. In the central nervous system it would seem that any 1 cell is not responsible for any particular response. Responses are elicited by whole groups of cells through their endings, and they they may not necessarily be neurons.
When something is repeated- like learning to type for example, a memory is created, when the neurons actually begin to grow to create pathways. When these pathways are created, a certain response to a stimulus will increase in efficiency. I dont think the neurons themselves have memory, but recalling past responses are made faster by this response to the learning and memory.
Serotonin-mediated endocytosis of apCAM: an early step of learning-related synaptic growth in Aplysia. Craig H. Bailey, Mary Chen, Flavio Keller and Eric R. Kandel.
Science v256.n5057 (May 1, 1992): pp645(5).
This article i know is not for humans, but it may clue to the way similar mechanisms may work, because such a mechanism has been studied in other mammals, includung one from Lima in Peru!! This is the literature i have read about it, but i knew that this was the case 😛