Where Alzheimer's starts and how it spreads

A new study involving 96 older adults initially free of dementia at the time of enrollment, of whom 12 subsequently developed mild Alzheimer’s, has clarified three fundamental issues about Alzheimer's: where it starts, why it starts there, and how it spreads.

Specifically, it begins in the lateral entorhinal cortex (LEC), a gateway to the hippocampus. Over time, Alzheimer's spreads from the LEC directly to other areas of the cerebral cortex, in particular the parietal cortex. It’s thought that it spreads by compromising the function of neurons in the LEC, which then compromises the integrity of neurons in adjoining areas.

Mouse models comparing the effects of elevated levels of tau in the LEC with elevated levels of APP, and with elevated levels of both, found that LEC dysfunction occurred only in the mice with high levels of both tau and APP. The LEC normally accumulates tau, making it more vulnerable to the accumulation of APP.

http://www.eurekalert.org/pub_releases/2013-12/cumc-ssw121713.php

[3582] Khan UA, Liu L, Provenzano FA, Berman DE, Profaci CP, Sloan R, Mayeux R, Duff KE, Small SA. Molecular drivers and cortical spread of lateral entorhinal cortex dysfunction in preclinical Alzheimer's disease. Nature Neuroscience [Internet]. 2014 ;17(2):304 - 311. Available from: http://www.nature.com/neuro/journal/v17/n2/full/nn.3606.html

Related News

One important reason for the greater cognitive problems commonly experienced as we age, is our increasing difficulty in ignoring distracting and irrelevant information. But it may be that in some circumstances that propensity can be used to help memory.

A number of studies have found that physical exercise can help delay the onset of dementia, however the ability of exercise to slow the decline once dementia has set in is a more equivocal question. A large new study answers this question in the negative.

Do older adults forget as much as they think, or is it rather that they ‘misremember’?

A Finnish study involving over 1000 older adults suggests that a counselling program can prevent cognitive decline even among those with the Alzheimer’s gene.

A pilot study involving 106 participants of the Rush Memory and Aging Project who had experienced a stroke followed participants for an average of 5.9 years, testing their cognitive function and monitoring their eating habits using food journals.

A small Japanese study has found evidence that those with amnestic mild cognitive impairment (aMCI) show a specific decline in their ability to recognize faces, and this is accompanied by changes in the way they scan faces.

Mild cognitive impairment (

A large study using data from the famous Framingham Heart Study has compared changes in dementia onset over the last three decades. The study found that over time the age of onset has increased while the length of time spent with dementia has decreased.

Data from more than 17,000 healthy people aged 50 and over has revealed that the more regularly participants engaged with word puzzles, the better they performed on tasks assessing attention, reasoning and memory.

Unplanned hospitalizations accelerate cognitive decline in older adults

Data from the Rush Memory and Aging Project has found that emergency and urgent hospitalizations are associated with an increased rate of cognitive decline in older adults.

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news