The Brain Plaques and Tangles That Cause Alzheimer’s Disease

The disease seems to develop as beta amyloid plaques and neurofibrillary tau tangles gather inside the brain to clog synapses and nerve cells—but what is its root cause?

There is certainly some controversy over what causes Alzheimer’s disease.  While two proteins—beta amyloid and tau—are prime suspects in its progression, uncertainty remains over what initially triggers this debilitating malady.  Knowing this origin of AD, be it amyloid or tau or some other source, is a key step toward developing possible treatments to stall or stop the disease.

Alzheimer’s disease manifests as clumps of protein in the brain.  Clumps that develop between nerve cells are called beta amyloid plaques (Aβ), while those that form from inside nerve cells are called neurofibrillary tangles, and are made of tau protein.  

In the progression of the disease, beta amyloid plaques precede tau tangles, and both are accompanied by inflammation in the brain and eventual neural loss.

Progression of Alzheimer's Disease 

Much of what has been learned about beta amyloid and tau has come from experiments done on mice, says Dr. Samuel Gandy, a researcher at Mount Sinai Medical Center.  Mice normally do not get Alzheimer’s disease, because their amyloid plaques do not clump.  Yet if a set of mutated genes are given to them, it causes build-up of amyloid and tau and the rodent brains become plaque-and-tangle-ridden in patterns similar to those that characterize Alzheimer’s disease.  If the mice are then given a substance that lowers the levels of tau alone, cognitive function returns, says Dr. Gandy.  "It's possible to sort of render the amyloid inert if you can turn down the tau, at least in the mouse model," says Gandy. 

Research has not yet made the jump from mouse to human, and amyloid and other components should not be dismissed in favor of solely tau-based research says Dr. Ottavio Arancio of Columbia University.  "It's perfectly possible that one of these abnormalities, let’s say amyloid, may trigger the rest," he says.  Further research into each of the many components at work in Alzheimer's disease is warranted, he adds, as any one could lead to a new understanding of how this disease works. 

The views expressed here are solely those of the participants, and do not represent the views of Big Think or its sponsors.

LinkedIn meets Tinder in this mindful networking app

Swipe right to make the connections that could change your career.

Getty Images
Swipe right. Match. Meet over coffee or set up a call.

No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.

Keep reading Show less

10 books to check out from Jordan Peterson's 'Great Books' list

The Canadian professor has an extensive collection posted on his site.

Jordan Peterson with Carl Jung and the cover art of Jaak Panksepp's 'Affective Neuroscience' (Image: Chris Williamson/Getty Images/Big Think)
Personal Growth
  • Peterson's Great Books list features classics by Orwell, Jung, Huxley, and Dostoevsky.
  • Categories include literature, neuroscience, religion, and systems analysis.
  • Having recently left Patreon for "freedom of speech" reasons, Peterson is taking direct donations through Paypal (and Bitcoin).
Keep reading Show less

Kosovo land swap could end conflict – or restart war

Best case: Redrawing borders leads to peace, prosperity and EU membership. But there's also a worst case.

Image: SRF
Strange Maps
  • The Yugoslav Wars started in 1991, but never really ended.
  • Kosovo and Serbia are still enemies, and they're getting worse.
  • A proposed land swap could create peace – or reignite the conflict.
Keep reading Show less

Should you invest in China's stock market? Know this one thing first.

Despite incredible economic growth, it is not necessarily an investor's paradise.

  • China's stock market is just 27 years old. It's economy has grown 30x over that time.
  • Imagine if you had invested early and gotten in on the ground floor.
  • Actually, you would have lost money. Here's how that's possible.