Senior Citizens Need to Avoid Distractions to
Improve Memory
Scientists find more evidence the aging brain is
easily distracted; highlights importance of hippocampus for making
memories
Nov. 27, 2008 Scientist have discovered something
that happens only in the brains of older people distractions over
power the ability to absorb information.
Annoying noise is behind their latest discovery of
unique brain activity underlying memory encoding failure that appears
to occur only in older brains, say scientists with the Rotman Research
Institute at Baycrest.
To date, few studies have looked at what's
happening in the brains of people who are having difficulty with making
a new memory and the underlying neural mechanisms responsible for this
break down.
In an interesting twist, this latest discovery was
made because of rather than in spite of the noisy environment that
research participants must tolerate when having their brains scanned
inside a donut-shaped magnet known as a functional magnetic resonance
imaging (fMRI) scanner.
While the powerful technology can yield remarkable
computerized images of the brain working to form a new memory, enabling
scientists to determine with great precision which brain regions become
active and for how long they remain active, the high powered magnet has
an inconvenient quirk it's noisy, especially if you're inside it.
In the Baycrest study, 12 younger adults (average
age 26) and 12 older adults (average age 70) took part in a face
recognition task that involved having their brains scanned with fMRI
while they were shown pictures of faces and later again when trying to
recall whether they'd seen each face before. (See below this story
associated research on face recognition.)
Researchers found that when younger and older
adults had difficulty encoding a new memory (certain face), this was
marked by decreased activity in brain regions important for encoding,
such as the hippocampus.
Other Reports on
this Research
Brain
scans show root of memory glitch with aging
By Malcolm
Ritter 20 hours ago
NEW YORK
(AP) Brain scans of older people in a noisy lab machine give
biological backing to the idea that distraction hampers memory with
aging, researchers reported Wednesday.
The finding
bolsters a theory about one reason why memory weakens with age: older
people have more trouble remembering some things because they're more
easily distracted when they try to learn them.
New research
supports the theory that distractions hinder memory as people age.
In the
study, which used brain scans of participants in a noisy lab machine,
researchers found that older people have more difficulty remembering
some things because they are more easily distracted as they try to
learn.
Although the
research involved the recognition of faces, scientists say the findings
apply to more general tasks of trying to remember something a person
sees or hears.
The researchers weren't surprised by this based on
an abundance of scientific evidence indicating the importance of
hippocampus for making memories.
But the older brains showed additional increased
activation in certain regions during memory encoding failure that was
not found in younger brains!
"The older brains showed increased activation in
certain regions that normally should be quieter or tuned down," said
Dale Stevens, who led the study as a psychology graduate at Baycrest's
Rotman Research Institute, with senior scientists Drs. Cheryl Grady and
Lynn Hasher, both of whom are distinguished researchers in aging,
memory, attention and distraction.
"The auditory cortex and prefrontal cortex, which
are associated with external environmental monitoring, were idling too
high. The older brains were processing too much irrelevant information
from their external environment basically the scanner noise," said Dr.
Stevens, who is now a post-doctoral fellow in the Department of
Psychology and Cognitive Neuroscience at Harvard University.
The younger brains did not show this abnormal high
idling during their failed memory encoding.
While older adults performed as well as their
younger cohorts in the number of faces correctly recognized, the older
adults forgot more faces overall than younger adults. The older adults
had more "misses", essentially saying "No, I didn't see this face
before" for faces that were presented previously. This was likely due in
part to their inability to tune out the distracting noise when they were
trying to form new memories of faces, said Dr. Stevens.
How noisy is an fMRI scanner?
The noise sounds similar to a "jack hammer" loud
banging, knocking and buzzing. Research participants are given hearing
protection (ear plugs and cushions around the head and ears) to block it
out, but older individuals complain more often than younger ones that
the noise is irritating.
The fMRI scanner is widely used for studies of the
aging brain, but are aging adults at a disadvantage in memory testing
because of the noise? It raises a potential confound or source of
contamination in data results that all cognitive researchers should be
aware of, Drs. Stevens and Grady point out.
"Not only are we reporting new brain evidence of
the well known problem of distraction in aging, but we show that the
fMRI might inherently make older adults' cognitive performance worse
than it would be in the real world, outside the scanner," noted Dr.
Grady.
Background Information
This latest finding follows a landmark study by Dr.
Grady, published in 2006 in the Journal of Cognitive Neuroscience.
In that investigation, she identified subtle changes in brain activity
that begin in middle age, which may underlie older adults' increasing
vulnerability to internal distraction and weakening concentration
skills. Dr. Grady found older adults have difficulty activating brain
regions necessary for concentration (such as reading) and de-activating
or tuning down other regions that are associated with internal thoughts
(such as thinking about yourself, what you did last night). This
inability to tune down internal thinking and tune up task-relevant
concentration becomes more pronounced after age 65.
Dr. Stevens' study focused on external
environmental distraction (from the fMRI scanner noise) and the
underlying neural markers that may explain why older adults seem to be
disproportionately distracted by this noise. Both scientists say their
studies reinforce a cautionary message to older adults: try to reduce
distractions in your external environment and make an effort to
concentrate on one key attentional task at a time.
This latest study, published in the Nov. 26 issue
of The Journal of Neuroscience, was supported by a Canadian
Institutes of Health Research grant. Baycrest is an academic health
sciences centre, internationally renowned for its care of aging adults
and its excellence in aging brain research, clinical interventions and
treatments, and promising cognitive rehabilitation strategies. It is
affiliated with the University of Toronto.
Carnegie Mellon scientists offer explanation for
'face blindness'
New research provides insight into intriguing
disorder
Nov. 27, 2008 - For the first time, scientists have
been able to map the disruption in neural circuitry of people suffering
from congenital prosopagnosia, sometimes known as face blindness, and
have been able to offer a biological explanation for this intriguing
disorder.
Currently thought to affect roughly two percent of
the population, congenital prosopagnosia manifests as the lifelong
failure to recognize faces in the absence of obvious neurological
damage, and in individuals with intact vision and intelligence.
Studying subjects aged 33 to 72 using diffusion
tensor imaging and tractography, the team of scientists from Carnegie
Mellon University, Kings College in London and Ben-Gurion University in
Israel were able to show that, unlike that of normal brains, there was a
reduction in the integrity of the white matter tracts in the brains of
individuals with congenital prosopagnosic.
Moreover, the extent of the reduced white matter
circuitry was related to the severity of the behavioral impairment.
The results are reported in the Nov. 23 online
issue of Nature Neuroscience.
White matter is one of the three main solid
components of the central nervous system. The white matter is the tissue
through which messages pass between different areas of grey matter
within the nervous system. People with congenital prosopagnosia are not
able to recognize faces, while the ability to recognize other objects
may be relatively intact.
This discovery of reduced white matter circuitry
could also lead to further understanding of other neurodevelopment
disorders, such as developmental dyslexia, in which the same underlying
neural alterations might be present. The findings are also important as
congenital prosopagnosia is, in many cases, inherited and so studies of
this sort can help us understand the relationship between genetics and
cortical development.
So far, few successful therapies have been
developed for affected people, although individuals often learn to use
feature-by-feature recognition strategies or secondary clues such as
hair color, body shape and voice. Because the face seems to function as
an important identifying feature in memory, it can also be difficult for
people with this condition to keep track of information about people,
and socialize normally with others.
"This disorder is also of great interest in helping
us understand how and under what conditions the brain is or is not
'plastic' as these individuals appear not to be able to compensate for
their inability to recognize faces even though they have had ample
opportunity to do so over the course of development," said Marlene
Behrmann, a professor of psychology at Carnegie Mellon.
Behrmann said the team was excited by the
possibility that the failure to propagate signals between different
regions of the brain might provide a biological explanation for this
perplexing disorder.
Background Information
About Carnegie Mellon: Carnegie Mellon is a
private research university with a distinctive mix of programs in
engineering, computer science, robotics, business, public policy,
science and social science, fine arts and the humanities. More than
10,000 undergraduate and graduate students receive an education
characterized by its focus on creating and implementing solutions for
real problems, interdisciplinary collaboration, and innovation. A small
student-to-faculty ratio provides an opportunity for close interaction
between students and professors. While technology is pervasive on its
144-acre Pittsburgh campus, Carnegie Mellon is also distinctive among
leading research universities for the world-renowned programs in its
College of Fine Arts. A global university, Carnegie Mellon has campuses
in Silicon Valley, Calif., and Qatar, and programs in Asia, Australia
and Europe. For more, see
www.cmu.edu.
Keep up with the latest news for senior citizens, baby
boomers
Nov. 27, 2008 Scientist have discovered something
that happens only in the brains of older people distractions over
power the ability to absorb information.