Alzheimer’s disease – where does it
originate from?
Scientists
have for the first time pinpointed the part of the brain where Alzheimer’s
originates, a finding that can lead to early diagnosis and better treatments
for the nuerodegenerative disease. Using high-resolution functional MRI
(fMRI) imaging in patients with Alzheimer’s disease and in mouse models of the
disease, Columbia University Medical Centre (CUMC) researchers have clarified
three fundamental issues about Alzheimer’s: where it starts, why it starts
there, and how it spreads.
In
addition to advancing understanding of Alzheimer’s, the findings could improve
early detection of the disease, when drugs may be most effective. ‘It has
been known for years that Alzheimer’s starts in a brain region known as the
entorhinal cortex,’ said co-senior author Scott A Small.
‘But this
study is the first to show in living patients that it begins specifically in
the lateral entorhinal cortex, or LEC. The LEC is considered to be a gateway to
the hippocampus, which plays a key role in the consolidation of long-term
memory, among other functions,’ Small said. The study also shows that,
over time, Alzheimer’s spreads from the LEC directly to other areas of the
cerebral cortex, in particular, the parietal cortex, a brain region involved in
various functions, including spatial orientation and navigation.
The
researchers suspect that Alzheimer’s spreads ‘functionally,’ that is, by
compromising the function of neurons in the LEC, which then compromises the
integrity of neurons in adjoining areas.
A third
major finding of the study is that LEC dysfunction occurs when changes in tau
and amyloid precursor protein (APP) co-exist. ‘The LEC is especially
vulnerable to Alzheimer’s because it normally accumulates tau, which sensitises
the LEC to the accumulation of APP. Together, these two proteins damage neurons
in the LEC, setting the stage for Alzheimer’s,’ said co-senior author Karen E
Duff. The researchers used a high-resolution variant of fMRI to map metabolic
defects in the brains of 96 adults. All were free of dementia at the time of
enrollment.
‘This
study has given us a unique opportunity to image and characterise patients with
Alzheimer’s in its earliest, preclinical stage,’ said Small.
The study
was published in the journal Nature Neuroscience.
24.12.2013
It’s official – women need more
sleep than men!
A new study has justified women’s usually grumpy behavior in
the mornings, suggesting that females need more sleep than men and odds are,
they don’t get enough.
Researchers at Duke University in Durham, North Carolina,
found that women undergo a lot of stress, both mentally and physically, during
the day and skimping on sleep only makes it worse, News.com.au reported.
Sleep-deprived women are more at risk of developing heart disease, depression,
psychological problems, and strokes, and have higher inflammation markers,
which are linked to pain, the study also found.
Dr Michael Breus said that the inflammation markers indicate
that women can literally be in more pain when they wake up than men. Breus
added that the study also showed that sleep-deprived women had more depression,
anger, and hostility early in the morning. It is worth noting that the study
also found that the state of a sleep deprived man’s health does not appear to
be closely linked to how much he sleeps.
24.12.2013
You are not only responsible for what you say, but
also for what you do not say
Martin Luther
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