New Optical Imaging of Brain Confirms Arteries More
Elastic in Fit Seniors
Discovery allows scientists to map pulse pressure and
elasticity of arteries in the brain with optical imaging, measure aging
19, 2014 - A new discovery can noninvasively image the pulse pressure
and elasticity of the arteries of the brain, revealing correlations
between arterial health and aging. Brain artery support, which makes up
the cerebrovascular system, is crucial for healthy brain aging and
preventing diseases like Alzheimer's and other forms of dementia.
The Beckman Institute, University of Illinois at
Urbana-Champaign, researchers led by Monica Fabiani and Gabriele Gratton,
psychology professors, routinely record optical imaging data by shining
near-infrared light into the brain to measure neural activity.
Their idea to measure pulse pressure through
optical imaging came from observing in previous studies that the
arterial pulse produced strong signals in the optical data, which they
normally do not use to study brain function.
Realizing the value in this overlooked data, they
launched a new study that focused on data from 53 participants aged
"When we image the brain using our optical methods,
we usually remove the pulse as an artifactwe take it out in order to
get to other signals from the brain," said Fabiani. "But we are
interested in aging and how the brain changes with other bodily systems,
like the cardiovascular system. When thinking about this, we realized it
would be useful to measure the cerebrovascular system as we worry about
cognition and brain physiology."
The initial results using this new technique find
that arterial stiffness is directly correlated with cardiorespiratory
fitness: the more fit people are, the more elastic their arteries.
Because arterial stiffening is a cause of reduced brain blood flow,
stiff arteries can lead to a faster rate of cognitive decline and an
increased chance of stroke, especially in older adults.
Using this method, the researchers were able to
collect additional, region-specific data.
"In particular, noninvasive optical methods can
provide estimates of arterial elasticity and brain pulse pressure in
different regions of the brain, which can give us clues about the how
different regions of the brain contribute to our overall health," said
"For example, if we found that a particular artery
was stiff and causing decreased blood flow to and loss of brain cells in
a specific area, we might find that the damage to this area is also
associated with an increased likelihood of certain psychological and
The researchers are investigating ways to use this
technique to measure arterial stiffness across different age groups and
specific cardiovascular or stress levels. High levels of stress,
especially over a long amount of time, may affect arterial health,
according to the researchers.
"This is just the beginning of what we're able to
explore with this technique. We're looking at other age groups, and in
the future we intend to study people with varying levels of long-term
stress," said Fabiani.
"When people are stressed for long periods of time,
like if they're caring for a sick parent, stress might generate
vasoconstriction and higher blood pressure, with significant
consequences for arterial function in the brain. We are interested in
knowing whether this may be an important factor leading to arterial
The researchers are also able to gather information
about pulse transit time, or how long it takes the blood to flow through
the brain's arteries, and visualize large arteries running along the
"Our goal is to find more information about what
causes arterial stiffness, and how regional arterial stiffness can lead
to specific health problems. Our findings continue to bolster the idea
that an important key to aging well is having good cerebrovascular
health," said Fabiani.
The technique and findings are detailed in an
article published in the journal Psychophysiology. Additional
support was provided by Beckman researchers Kathy Low, Chin-Hong Tan,
Benjamin Zimmerman, Mark Fletcher, Nils Schneider-Garces, Edward Maclin,
Antonio Chiarelli, and Brad Sutton. It was supported by the National
Institute on Aging and the National Science Foundation.