Neural connections with age-related decline

In early spring 2019, the Institute for Society, Culture and the Environment (ISCE) held a National Science Foundation Career Symposium
for social science researchers.
Ben Katz, assistant professor of human development in the College of Arts and Sciences, and Tae-Ho Lee, assistant professor of psychology in the College of Science, among others, participated in the day's event
.
Professor Lee, who has just been hired by Virginia Tech, has begun preparing a human and animal aging program
with Il Hwan Kim, an assistant professor at the University of Tennessee Health Sciences Center.
The two, friends who have collaborated for years while pursuing their degrees, are using animal and human models to study the role
that the blue-spotted circuit plays in age-related cognitive decline.
Initially, Lee and Kim devised a circuit-manipulating approach to demonstrate causality on rodent models, "looking at behavioral changes before and after circuit rescue in animal brains," Lee said
.

When Lee and Kim met Katz, they were considering adding an additional human intervention design that might resemble an animal circuit rescue model
.
Katz's areas of interest include cognitive training and age-related decline
.
Their encounter was accidental
.

Three years later, Lee, Kim and Katz's team received a five-year, $3.
8 million grant
from the National Institute on Aging for their study, "Loss of Specificity: The Role of Blue Spot Sites in Age-Related Distraction.
" Specifically, researchers are looking at attention networks in the brain, with the goal of studying how these networks are connected or disconnected
to each other when a person is trying to concentrate in a distracting or stressful environment.

One of the areas of focus is focused on the blue spot, which plays a role in determining which neural resources in the brain need to be involved in certain cognitive processes, such as decision-making and executive functions
.
The other is the prominent network, which is made up of circuits throughout the brain that act together to prioritize what information to process
.
The connection between the two networks is critical to successful attention processing, including avoiding distractions
.

"Our goal is to find mechanisms
that might inform effective interventions and programs for age-related cognitive decline," Katz said.
The idea is to be able to identify and measure blue spots and significant network connections
in distracted situations.
We also wanted to see if there were connectivity differences
between people at highest risk of developing Alzheimer's or dementia and those at highest risk of developing Alzheimer's or dementia.
”

These networks naturally decline
with age.
Katz, Lee and Kim wanted to compare the connectivity of the two networks between older and younger adults to determine whether this had any effect on participants at risk of dementia and to see if older adults improved
connectivity after cognitive training.

Each researcher has their own expertise
.
"I'm interested in
how brain circuitry, particularly the blue spot, optimizes behavior and responds to the environment," Lee says.
"I found that the function of the blue spot declines with age, so other subsequent cognitive processes also deteriorate
.
" The network of blue spots in the brain has been linked to the risk of dementia, but because of its small size and location in the brainstem, it is a difficult area
to study.

"Looking at this region, imaging and analyzing the blue spot, which is actually a very small region of interest, can be challenging to get good usable data in this regard
," Katz said.
But Tae-Ho is an expert in
imaging the blue spot.
”

Neurobiologist Kim has been able to locate neural trajectories
between blue spot sites and prominent networks in rodents.
Professor Lee said: "He is a rare scientist
who can directly change the activity of circuits between specific regions.
Circuits lead to behavioral changes, which proves a causal relationship
between animals.
"That's what they're aiming for in humans — to provide further evidence
of causality.
"

Using cognitive training, the equivalent of animal circuit manipulation and rescue, comparing brain connections between blue-spotted sites and prominent networks before and after training will allow Katz to better infer cause and effect, just like animal models
.

Katz said: "The idea is to understand and identify the neurophysiological mechanisms responsible for better attention and resistance to distractions
.
This will help us understand the neural mechanisms that support attention differences, and then let's target those mechanisms
.
This will take us to the next step
.
”

The next step is intervention
.

The researchers noted that while a person may have a genetic risk of developing Alzheimer's, this does not guarantee that he will necessarily get Alzheimer's
.
In this study, they wanted to see how connectivity differs
between at-risk and non-at-risk people.

So far, interventions have not been successful in slowing or reversing the decline
in attention associated with Alzheimer's disease.
If Lee, Katz and Kim can find specific physical mechanisms that cause age-related decreased attention span, this could open the door
to further research into interventions to reduce this decline.

However, individuals at risk of developing Alzheimer's are not the only potential target for
this research direction.
Since the study was about distraction, it affected people of all ages, and their findings may also be relevant
for children and adults with attention deficit disorder.