Think back to your fondest memory. If a group of Johns Hopkins University researchers are right, you just changed that memory forever. They've developed a new theory about the nature of memory that could resolve a longstanding debate about the issue, Scientific American explains. They believe that memories are initially encoded through the efforts of your hippocampus and cortex. Thereafter, whenever you access the memory, your hippocampus tells your brain where to move it or how to change it.
Oft-revisited memories will quickly take up residency as permanent residents of the cortex, while their lesser-touched comrades fade away. In the past, some scientists had hypothesized that new memories form in the hippocampus, then gradually migrate to the cortex as they age, while others believed that "episodic" memories are the province of both organs, while dryer, more factual observations end up in the cortex. But neither explained every case. This new theory postulates that it's not the nature or age of the memory that determines where it lands, but how you use it.