By John Salak –
It’s hard not to be spooked by memory loss. It happens to everyone, but it gets significantly worse as people age. Alzheimer’s is, of course, the most notorious and debilitating related condition and is nothing to joke about. But scientists out of Ireland now claim that losing some memories may not be a bad thing at all. In fact, they argue that in some cases it could be a form of learning.
Researchers from Trinity College in Dublin explained that losing some memories while retaining others may be a functional feature of the brain, allowing it to interact dynamically with the environment. Under this process, the brain is reacting to certain environmental feedback and predictability in degerming which memories are worth retaining. Ultimately, forgetting some memories can be a boom that leads to more behavioral flexibility and better decision-making.
“If memories were gained in circumstances that are not wholly relevant to the current environment, forgetting them can be a positive change that improves our wellbeing,” the team explained in a statement. Admittedly they acknowledge that losing a memory means some information is lost. But they pointed to other research that maintains this lapse can be the result of the brain limiting access to information rather than what’s thought of as traditional memory loss.
“Memories are stored in ensembles of neurons called ‘engram cells’ and successful recall of these memories involves the reactivation of these ensembles. The logical extension of this is that forgetting occurs when engram cells cannot be reactivated. The memories themselves are still there, but if the specific ensembles cannot be activated, they can’t be recalled. It’s as if the memories are stored in a safe but you can’t remember the code to unlock it,” reported Dr. Tomás Ryan, a Trinity associate professor.
“Our new theory proposes that forgetting is due to circuit remodeling that switches engram cells from an accessible to an inaccessible state. Because the rate of forgetting is impacted by environmental conditions, we propose that forgetting is actually a form of learning that alters memory accessibility in line with the environment and how predictable it is.”
There are different ways that trigger memory loss, which all involve making it more difficult to access an engram, the Trinity team added. Ultimately, the insights gained may also have implications for disease-driven memory loss. “Importantly, we believe that this ‘natural forgetting’ is reversible in certain circumstances and that in disease states—such as in people living with Alzheimer’s disease for example—these natural forgetting mechanisms are hijacked, which results in greatly reduced engram cell accessibility and pathological memory loss,” the team reported.