A team of scientists has discovered that a memory rather than a partial memory loss is liable to cause mental confusion in patients with dementia.
An international team of scientists has discovered that a memory rather than a partial memory loss is liable to cause mental confusion in patients with dementia.
Presented in the journal Science, the study clarifies how the brain’s ability to maintain complete and detailed memories is disturbed, potentially reversing the theories under which it is by forgetting past events and objects to cause memory problems. According to the researchers, the remaining memories sketched confuse patients, increasing the chances of erroneously recalled information that they never acquired.
The researchers, led by the University of Cambridge, used an animal model of amnesia widely used to determine an impairment of memory. In previous studies on memory it was discovered that animals suffering from amnesia could not distinguish between new and old objects. But these studies did not show whether the animals were unable to make the difference between objects because they thought the object was old again (and then forgetting something that had happened) or because they decided that the new object was old (false memory).
In this latest study, subjects were exposed to an object of study, were subsequently subjected to a test in which the object of study was presented again, along with a new object perceptually distinct. The subjects had to make the difference between the object and the new resume. This allowed the researchers to assess the reaction to the object the new and old separately.
The animals looked at an object and then underwent an hour after a memory test involving the same object or a new object. The animals easily spent more time exploring the new object, indicating that they remembered the old object.
While the animals suffering from amnesia reported poor results in this test. They spent as much time exploring the new object is that the old one. The researchers also found that these animals spent less time exploring the new object compared to the animals ‘normal’. Animals with amnesia had false memories about the new object.
The team considered whether the performance in these tasks related to better memory in the absence of other memories to confuse the brain. The animals were placed in a dark space and quiet before being tested. The researchers found that animals suffering from amnesia who did not show to remember when they passed the time before the test under normal conditions, showed a perfect memory when it passed the time prior to the test in a dark and silent.
“The study suggests that a key component of memory problems may actually be a confusion between memory and the other rather than memory loss itself,” says Dr. Lisa Saksida the Department of Experimental Psychology University Cambridge, one of the authors of the study. “This is consistent with descriptions of distortion of memory in dementia – for example, patients do not forget to turn off the stove or take medicine, not because they forget to do these things but because I think I’ve already done,” he adds.
“One thing that surprised us a lot about our results was the extent of recovery of memory simply by reducing the information received by the subjects before the memory test,” she says. “This achievement not only runs counter to our predictions, but allows us to better understand the possible nature of memory impairments that are the basis of certain types of amnesia and dementia, which is essential to develop more sophisticated and effective treatments.”
The scientists believe their findings could lead to new treatments to mitigate the confusion of memories, including drugs that amplify the complex and detailed representations necessary to separate the memories.
“Even more exciting is the possibility of developing treatments that can stop the disease in its early stages, compared with treatments that counteract the symptoms once the dementia has already occurred,” says Dr Saksida. “Early detection of an impairment of memory is crucial for the development of such care and understanding of the nature of the disability, as we have done here, is crucial for the early diagnosis.”
Contributors to this study, researchers from the Wellcome Trust Behavioural and Clinical Neuroscience, University of California, San Diego, United States, and the University of Guelph, Canada.
