14 DAY TRIAL // University of Cambridge researchers carried out a study that explains why people suffering from dementia have memory difficulties – the memories are not lost, but rather confused, since the brain forms incomplete memories that get mixed up.
Until now, everyone thought that having memory problems means forgetting previous events, items or individuals, but Dr Lisa Saksida, from the Department of Experimental Psychology at the University of Cambridge, said that “this study suggests that a major component of memory problems may actually be confusion between memories, rather than loss of memories per se.
“This is consistent with reports of memory distortions in dementia - for example, patients may not switch off the cooker, or may fail to take their medication, not because they have forgotten that they should do these things, but because they think they have already done so.”
Previous research assessing mice memory, concluded that amnesic animals cannot make the difference between an old and a new object.
But this time, the researchers went even further and tried to find out whether the animal could not distinguish between the objects because it saw the old object as being new (forgetting something that happened), or because it saw the new object as being old (false memory).
Their latest experiment proved that in amnesic animals, the brain's ability to maintain complete, detailed memories was interfered with, which means that the memories were less detailed and more easily confused, leading to false memories.
Also, the researchers discovered that if they managed to eliminate other memories that could confuse the brain (like a busy environment) before a memory test, then they could improve the mice's performance on the memory task.
“One thing that we found very surprising about our results was the extent of the memory recovery, achieved simply by reducing the incoming information prior to the memory test,” added Dr Saksida.
"Not only does this result confound our expectations, but it also gives us a clearer understanding of the possible nature of the memory impairment underlying amnesia and certain types of dementia, which is critical to developing more sophisticated and effective treatments.
“This also tells us something about how detrimental interference from other things can be when we are trying to remember something, an issue that may be increasingly relevant as the number of potential distractions in our daily lives seems to be on the rise.”
The researchers believe that their experiment is a first step that can bring them closer to new treatments, that would reduce memory confusion and enhance the details that are necessary to separate memories.
“Alternatively, deliberate and intentional use of the details differentiating objects and events might be a strategy that could prolong independence and help to improve daily functioning for patients.
“Even more exciting would be the ability to develop treatments that could stop the disease in the early stages, rather than treatments that address the symptoms once dementia has set in.
“Early detection of memory impairment is critical for the development of such treatments, and a better understanding of the nature of the impairment, as we have found here, is critical to such early detection,” added Dr Saksida.
This research received additional support from the Medical Research Council and the Wellcome Trust through their funding of the University of Cambridge's Behavioral and Clinical Neuroscience Institute.
The results are published today in the journal Science.