From what I understand, your brain stores I information by association. So it's possible that your brain was activating an old neaural pathway that had a releva

From what I understand, your brain stores I information by association. So it's possible that your brain was activating an old neaural pathway that had a relevant connection to what you were learning. As an example, if you have trouble remembering people's names. Picture the face of someone you remember with the same name on top of the new persons face. This will cut out a lot of work for your brain, as it will utilize an existing pathway. This is why something random can sometimes trigger a memory we didn't expect. It's more complicated then that of course, but that's the idea.