A Johns Hopkins neuroscientist has shed light onto why age makes remembering new things more difficult.
According Michael Yassa, the real trouble is that our aging brains are unable to process this information as "new" because the brain pathways leading to the hippocampus-the area of the brain that stores memories-become degraded over time. As a result, our brains cannot accurately "file" new information and confusion results.
Yassa and his team used MRI scans to observe the brains of 40 healthy young college students and older adults, ages 60 to 80, while these participants viewed pictures of everyday objects such as pineapples, test tubes and tractors and classified each-by pressing a button-as either "indoor" or "outdoor."
Later, the participants viewed a series of completely new pictures (all different) and again were asked to classify them as either "indoor" or "outdoor." A few minutes later, the researchers presented the participants with the new set of pictures and asked whether each item was "old," "new" or "similar."
"The 'similar' response was the critical response for us, because it let us know that participants could distinguish between similar items and knew that they're not identical to the ones they'd seen before," said Yassa, assistant professor of psychological and brain sciences in Johns Hopkins' Krieger School of Arts and Sciences.
"We found that older adults tended to have fewer 'similar' responses and more 'old' responses instead, indicating that they could not distinguish between similar items," added Yassa.
Yassa said that this inability among older adults to recognize information as "similar" to something they had seen recently is linked to what is known as the "perforant pathway," which directs input from the rest of the brain into the hippocampus. The more degraded the pathway, the less likely the hippocampus is to store similar memories as distinct from old memories.
The study is detailed in Early Online edition of the Proceedings of the National Academy of Sciences.