A team of US and Japanese scientists1 have shown that memories form simultaneously in the hippocampus (short-term memory storage) as well as the cortex (long-term memory storage). This is very surprising, because since 1950s the mechanism was thought to be a cascade – first short-term memory then transfer to long-term memory.
On the other hand the significance of the hippocampus didn’t go straight to zero. Without a well working hippocampus the memories in the cortex don’t get enabled or don’t mature.
Nevertheless the potential implications of this discovery might be enormous for treatments of neurological diseases.
While the article stays behind a paywall, here’s a place where you can read about the memory engram technology used in the study