Is déjà vu a real memory event you could learn to trigger?

The feeling of having-been-here-before arrives whole and then dissolves, leaving you with nothing you can point to, no earlier scene, just a strong certainty or awareness that this has happened before. We can read it in two ways: a genuine memory misfiring, maybe some near-match retrieved without its source, or a raw familiar memory firing on its own; or it could be a genuine ability to see temporarily into the future. Either way, can this feeling be deliberately reproduced or sharpened, or is it just another glitch of attention and memory?

open-question·neuroscience·memory