Why does memory fade? Why does it stay?
These questions, among others, occupy the mind of Charan Ranganath, a 澳门六合彩开奖结果走势图 psychology professor in the 澳门六合彩开奖结果走势图 College of Letters and Science and a core faculty member with the Center for Neuroscience. But the transient nature of memory isn鈥檛 just a focal point of Ranganath鈥檚 research. It鈥檚 something that he, like the rest of us, deals with daily.
![Charan Ranganath, in a lab coat, adjusting wires on a research subject.](/sites/default/files/images/article/charan-ranganath_lg.jpg)
鈥淎s a memory researcher, the most common question that I get in my everyday life is, 鈥榃hy am I so forgetful?鈥欌 Ranganath said.
For Ranganath, forgetfulness often manifests as a misplaced pair of glasses or smartphone. But for others, memory lapses can be a sign of something more concerning.
Post-traumatic stress disorder, schizophrenia, Alzheimer鈥檚 disease and other neurological conditions all affect memory. However, diagnoses of a condition like Alzheimer鈥檚 often come too late for effective intervention.
鈥淏y the time you reach this point, there鈥檚 already significant damage in the brain,鈥 said Ranganath, who also directs the 澳门六合彩开奖结果走势图 Memory and Plasticity Program. 鈥淲e need to detect people not at this point but rather at an earlier point, where people are just starting to deviate from the healthy trajectory of aging.鈥
In Ranganath鈥檚 lab, he and his colleagues are developing biomarkers to identify individuals with preclinical Alzheimer鈥檚 disease. The hope is that early detection will allow for successful intervention.
Why do we forget?
The brain is a marvel of evolution. Yet even the healthy brain, according to Ranganath, isn鈥檛 designed to remember everything. A host of factors contribute to this daily forgetfulness.
鈥淭he biggest culprit in probably our everyday life is multitasking,鈥 Ranganath said. 鈥淲e don鈥檛 remember things often because we were never there in the first place. We鈥檙e checking our phones, being distracted by noises on the street and so forth, and all these things really degrade our capability to remember.鈥
Stress, fatigue and lack of sleep are also contributors to forgetfulness.
鈥淲hen we鈥檙e under stress, we often have trouble forming new memories,鈥 Ranganath said. 鈥淎nd as we get older, we definitely get less sleep and that leads to fatigue during the daytime, but also impairs our ability to solidify our memories during the night when we normally sleep.鈥
Why do we remember?
For Ranganath, a more pertinent question than 鈥淲hy do we forget?鈥 is 鈥淲hy do we remember?鈥
It turns out that memory serves different purposes throughout a human lifespan. For adults, memory is often used to achieve goals or to assist with familial/communal activities. For children, it鈥檚 harnessed to build a sense of self, to explore the world and to learn. And in older adults, memory assists with cultural transmission 鈥 the passing of knowledge to the next generation.
Though memory plays different roles during a person鈥檚 life, there are steps one can take to promote healthy brain aging.
In a recent study, published by the and referenced by Ranganath, researchers tracked roughly 29,000 participants over 10 years and discovered that a healthy lifestyle was associated with a slower memory decline. The six healthy lifestyle factors measured in the study included a healthy diet, regular physical exercise, active social contact, active cognitive activity, never or previously smoked and never drinking alcohol.
鈥淭he people with the most favorable lifestyle maintained more of their memory functions over this 10-year period than people who maintained an unfavorable lifestyle,鈥 Ranganath said. 鈥淚t鈥檚 quite a significant and meaningful difference.鈥
Detecting hidden signs of Alzheimer鈥檚
While maintaining a healthy lifestyle promotes healthy brain aging, it鈥檚 not a panacea. As Ranganath said, 鈥淎ll of us know somebody who could鈥檝e lived a very healthy lifestyle and still, nonetheless, succumbed to neurodegenerative disease.鈥
That鈥檚 why Ranganath and his team are developing biomarkers to detect preclinical Alzheimer鈥檚 disease. They鈥檝e focused their sights on an area of the brain called the lateral entorhinal cortex (LEC).
鈥淭he LEC is important because it鈥檚 ground zero for damage in preclinical Alzheimer鈥檚 disease,鈥 Ranganath said. 鈥淭his is the stage we can鈥檛 identify in typical adults.鈥
The type of LEC damage characteristic of preclinical Alzheimer鈥檚 disease isn鈥檛 easily ascertained in living patients. Oftentimes, to glimpse such damage, a researcher needs to view a slice of a brain sample under a microscope. Ranganath and his team are figuring out how to assess this pathology in a noninvasive way.
鈥淭he brain is an interconnected network and even if only one area is showing pathology, like the LEC, we can see how it can affect memory in a broader way,鈥 Ranganath said. 鈥淏y doing this, we can understand how subtle dysfunction in the LEC can cause age-related and pathological changes in memory that we can measure in larger areas of the brain, like the hippocampus.鈥
鈥淭hrough basic and translational neuroscience partnerships, we鈥檙e hoping to be able to build new treatments for detection and intervention of Alzheimer鈥檚 disease,鈥 he added.
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Greg Watry is a science writer in the 澳门六合彩开奖结果走势图 College of Letters and Science. This article was originally published on the college's website.