There are plenty of studies probing the memories of senior citizens. Young people, like the easily recruited college students who participate in psychological research, are also disproportionately represented in the literature. But what about middle-aged folks? The memories of this oft-neglected group are getting some much-needed attention in a new study published in the journal Cerebral Cortex.
Binghamton University psychologists gathered a group of adults whose ages ran the gamut from 18 to 74, loaded them into an MRI machine, and gave them an associative memory test. The participants were shown a series of faces alongside objects or scenes and asked to imagine the individuals interacting with them to facilitate memory encoding. After a five-minute break, they were then shown the pictures of faces and asked to recall the objects/scenes.
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According to the researchers, the experiment was designed to mimic how episodic memory encoding functions. The brain first records the information, the hippocampus revisits the memory to encode it, and, once stabilized, the brain can retrieve it.
They found that middle-aged participants often matched a face with the wrong object or scene. Basically, they knew that they recognized it, but couldn’t accurately place it. “It becomes hard because now all of these images on the screen during the test seem familiar,” study author Ian McDonough explained in a statement. “They know they’ve seen all of these before, but now what they have to remember is that specific link. And that’s where, as people age, they start to really show these errors.”
The researchers thought any potential slips in the middle-aged would be associated with weaker hippocampal activity, but that wasn’t the case. While young people’s retrieval errors were marked by a failure to activate the original memory patterns, middle-aged participants still showed strong hippocampal activation.
“The more they reactivate the hippocampus that’s consistent with encoding, the more likely they are to make these memory errors,” McDonough said. “So instead of that reactivation pattern being associated with better memory, it’s associated with those errors.”
Unfortunately they don’t know why strong activation of the hippocampus results in misremembering. Still, the findings suggest that middle-age memory is a lot more interesting than previously thought, with deficits appearing earlier than anticipated.
“We really don’t have a good scientific understanding of what is happening in middle age, because the brain isn’t declining uniformly across this time, with some regions declining faster than others,” McDonough said. “Finding when those tipping points are is going to be important.”
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Lead Image: Jorm Sangsorn / Shutterstock
