“As people age—even in good health—the brain becomes less precise about how different categories of visual information are represented in the visual cortex. This age-related decline in neuronal selectivity, or heterogeneity, is linked to deterioration in memory performance. “
A new study, published in Journal of Neurosciencesuggesting that this decline in memory is actually linked to more complex brain mechanisms than previously thought.
Memory: Declining neuronal selectivity in seniors
As part of their work, researchers from the Center for Vital Longevity at the University of Texas in the United States analyzed data from 48 healthy adults, half of whom had an average age of 22 years. And another was 69 years old. Using old functional MRI techniques, they examined participants’ brain activity while they viewed and processed images of life scenes or objects. They were shown some images multiple times, allowing them to measure the brain activity produced by both image categories and individual objects.
Regarding image categories, scientists have discovered, “As expected, the older group showed less preference for life scenes than the younger group, but not for objects”, we can read in the press release. But in terms of individual elements, it appeared “The older group had reduced preferences for both scenes and objects.”
Age-related cognitive decline: distinct neural mechanisms depending on the situation
“This means that the mechanisms driving differentiation at the single-item level are not the same as those at the category level. We have assumed until now that they are one and the same mechanism.”, explains Dr Michael Rugg, who led the work. In other words, knowing how selective a person’s brain is for categories does not predict how selective it will be for individual elements: the neural mechanisms at work are simply different.
“There is no universal theory of age-related neuronal differentiation, A psychology professor concludes. This has important consequences for how we understand and study age differences in neuronal selectivity, some measures of which predict memory performance.”
These results, according to him, should invite scientists “Be more careful in how they generalize what they see at the category level to what’s happening more broadly in the aging brain.”. Understand: There are other independent factors that lead to a decline in choice in older people. which? This will be the subject of future research, promise the study’s authors.
