Brain tangles associated with Alzheimer's also occur in normal aging

May 19, 2003

CHICAGO --- Accumulation of neurofibrillary tau tangles not only causes the memory loss that occurs in Alzheimer's disease but also may be responsible for the memory deficits seen in normal aging and in some cases of mild cognitive impairment, a study from Northwestern University and the University of Miami has found.

Mild cognitive impairment is isolated memory loss more severe than what is associated with "normal aging," but without the additional cognitive difficulties or disruptions of daily living activities characteristic of Alzheimer's disease.

Individuals with mild cognitive impairment have been shown to develop Alzheimer's at a higher rate than those without cognitive impairment, suggesting that mild cognitive impairment may represent an intermediate stage between aging-related memory loss and Alzheimer's disease.

Angela L. Guillozet, a researcher in the Cognitive Neurology and Alzheimer's Disease Center at Northwestern University, and colleagues reported in the May issue of Archives of Neurology that neurofibrillary tangles are more numerous in brain regions associated with memory function and correlate with performance on memory tests in cognitively normal elderly persons and those with mild cognitive impairment.

The group's study also showed that beta-amyloid plaques, the other diagnostic marker for Alzheimer disease -- which some researchers believe cause the memory-robbing neurodegeneration that occurs in Alzheimer's -- do not play a significant role in cognitive status prior to the development of Alzheimer's disease.

The researchers investigated tangle distribution in the brain and neuropsychological test results in five persons with no cognitive impairment and three with mild cognitive impairment who had agreed to donate their brain after death. The last test occurred between 15 days and a little over a year before death.

They found that individuals with mild cognitive impairment had higher densities of neurofibrillary tangles than did nonimpaired persons. In addition, tangle density in brain regions associated with memory function correlated with scores on memory tests, but density of beta-amyloid did not.

Results of their study indicate that neurofibrillary tangles may constitute the basis of memory loss not only in Alzheimer's disease but also in normal aging and mild cognitive impairment. Further, the results seem to confirm findings from other studies that discerned no relationship between amyloid distribution and dementia severity in Alzheimer's disease.

Guillozet is postdoctoral student at the Feinberg School of Medicine at Northwestern University. Her co-researchers at the Feinberg School were Sandra Weintraub, professor of psychiatry and behavioral sciences and M.-Marsel Mesulam, M.D., Ruth and Evelyn Dunbar Professor of Psychiatry and Behavioral Sciences, professor of neurology and director of the Cognitive Neurology and Alzheimer's Disease Center. Deborah C. Mash of the University of Miami School of Medicine also contributed to the study.

This study was supported by grants from the National Institute on Aging and from the National Institute of Neurological Disorders and Stroke, National Institutes of Health.
-end-


Northwestern University

Related Memory Articles from Brightsurf:

Memory of the Venus flytrap
In a study to be published in Nature Plants, a graduate student Mr.

Memory protein
When UC Santa Barbara materials scientist Omar Saleh and graduate student Ian Morgan sought to understand the mechanical behaviors of disordered proteins in the lab, they expected that after being stretched, one particular model protein would snap back instantaneously, like a rubber band.

Previously claimed memory boosting font 'Sans Forgetica' does not actually boost memory
It was previously claimed that the font Sans Forgetica could enhance people's memory for information, however researchers from the University of Warwick and the University of Waikato, New Zealand, have found after carrying out numerous experiments that the font does not enhance memory.

Memory boost with just one look
HRL Laboratories, LLC, researchers have published results showing that targeted transcranial electrical stimulation during slow-wave sleep can improve metamemories of specific episodes by 20% after only one viewing of the episode, compared to controls.

VR is not suited to visual memory?!
Toyohashi university of technology researcher and a research team at Tokyo Denki University have found that virtual reality (VR) may interfere with visual memory.

The genetic signature of memory
Despite their importance in memory, the human cortex and subcortex display a distinct collection of 'gene signatures.' The work recently published in eNeuro increases our understanding of how the brain creates memories and identifies potential genes for further investigation.

How long does memory last? For shape memory alloys, the longer the better
Scientists captured live action details of the phase transitions of shape memory alloys, giving them a better idea how to improve their properties for applications.

A NEAT discovery about memory
UAB researchers say over expression of NEAT1, an noncoding RNA, appears to diminish the ability of older brains to form memories.

Molecular memory can be used to increase the memory capacity of hard disks
Researchers at the University of Jyväskylä have taken part in an international British-Finnish-Chinese collaboration where the first molecule capable of remembering the direction of a magnetic above liquid nitrogen temperatures has been prepared and characterized.

Memory transferred between snails
Memories can be transferred between organisms by extracting ribonucleic acid (RNA) from a trained animal and injecting it into an untrained animal, as demonstrated in a study of sea snails published in eNeuro.

Read More: Memory News and Memory Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.