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Researchers in the United States have uncovered a surprising new indicator of cognitive decline and dementia: a change in exploration behavior by middle age.

Their study found that middle-aged adults are less efficient explorers in a maze learning task compared to younger individuals. This finding opens new avenues for diagnosing and treating cognitive decline.

Spatial navigation, the daily skill of moving from one place to another, typically deteriorates with age. This decline has long been attributed to worsening spatial memory due to natural changes in brain structure and function. However, researchers suggest that altered exploration behavior, observed in aging animals and now humans, also plays a significant role.

Lead author Dr. Vaisakh Puthusseryppady, a postdoctoral researcher at the University of California, Irvine, highlighted the study's key findings.

"Compared to younger individuals, middle-aged people exhibit overall less exploration when learning a novel maze environment, and seem to be prioritizing learning specific important locations in the maze as opposed to the overall maze layout," he said, as quoted by PsyPost.

The study, published in Frontiers in Aging Neuroscience, involved 87 middle-aged participants, averaging 50 years old, and 50 young participants, averaging 19 years old, all without any history of neurological or psychiatric diseases. Participants navigated a virtual reality maze during two phases: an exploration phase to learn the maze and a wayfinding phase to apply their knowledge.

Results showed that young participants had a higher success rate in navigating the maze. However, statistical analyses revealed that middle-aged participants' reduced success was partly due to their different exploration behaviors.

Dr. Mary Hegarty, a professor at the University of California, Santa Barbara, noted the significance of these differences, saying, "Compared to younger individuals, middle-aged individuals explored the maze environment less, as they traveled less distance, paused for longer periods of time at decision points, and visited more objects than young individuals."

The researchers speculate that these behavioral changes may be linked to age-related alterations in the brain's navigation network, such as the medial temporal and parietal lobes. The findings suggest that training middle-aged adults to explore novel environments more effectively could help improve their spatial memory and slow cognitive decline.

Co-author Daniela Cossio, a PhD student at UC Irvine, emphasized the potential applications.

"If we were to train middle-aged people to explore novel environments better -- with a focus on traveling greater distances, visiting paths that connect the environment, in a more spread-out manner -- this might lead to improvements in their spatial memory, helping to slow down their decline in cognitive ability," she explained.

Dr. Elizabeth Chrastil, an associate professor at UC Irvine, expressed optimism about future research.

"We are currently investigating whether these kinds of changes in exploration behavior can be identified in people at risk of Alzheimer's Disease, as well as in those who actually have Alzheimer's. We anticipate that altered exploration behavior could ultimately become a novel clinical marker for early cognitive decline related to Alzheimer's," she said.

This study not only sheds light on the underlying causes of age-related cognitive decline but also paves the way for new diagnostic and therapeutic strategies.