Using medical imaging, to compare the brain activity of 93-year olds to that of healthy people from 18-93 years old, scientists from Harvard University discovered that aging results in the decrease in the brain's white matter that enables effective communication between one area and another.
This decrease in the amount of white matter, which serves as the brain's wiring, was identified to be causing the loss of mental agility, disabling an individual from performing "higher" cognitive functions, like memory storing and learning.
"This research helps us to understand how and why or minds change as we get older, and why some individuals remain sharp in their 90s, while other's mental abilities decline as they age," explained lead researcher Jessica Andrews-Hanna.
She further explained that the loss of proper synchronicity, or "cross-talk", between brain parts of the brain lead to a less efficient mental functioning, affecting the quality of mental ability, stated a BBC article.
The experiment's methodology involved the researchers asking subjects to perform mental exercises, such as identifying whether particular words referred to living or nonliving objects. Monitoring was done by the scientists throughout the test, observing the functions of the white matter by observing water movement along specific parts via MRI.
Scientific American said that Harvard cognitive neuroscientist Randy Buckner explained that strong communication is depicted by water flowing "as if cascading down a celery stalk." A scattering of the water signifies decreased communication quality - something that was apparent in the older group of subjects.
The study, the results of which were published in Neuron, was co-authored by other Harvard researchers, along with the collaboration of scientists from the University of Michigan , and Washington University.
