Why Some People Get Alzheimer’s and Others Don’t

Many people who don't develop dementia are nonetheless discovered after their deaths to have the brain lesions associated with Alzheimer's disease.

It has been a surprise in Alzheimer’s disease research that a substantial number of people who never had dementia are discovered after their deaths to have the kinds of brain lesions associated with the disease. Dr. Juan Troncoso, a researcher at the Brain Resource Center at Johns Hopkins University, says in Big Think's Breakthroughs series that this is evidence that some individuals are able to resist the onset of Alzheimer’s.

What these individuals are resilient against is the toxic buildup in the brain of a fibrous protein called amyloid. This material, says Dr. Samuel Gandy of Mount Sinai Hospital, is made by cells throughout the body, throughout one's life, largely to no effect—until a certain point.

"For reasons we don’t understand, in certain regions of the brain, it changes its shape," says Gandy. The amyloid proteins form clumps that are poisonous to nerve cells. This poisoning of the brain from amyloid—known as the amyloid hypothesis—is a prevailing theory as to how the disease dissolves neurons, clogging the brain with the debris of dead cells. This, in turn, leads to dementia and eventually to death.

Those individuals who have been found with amyloid buildups in the brain but without dementia are, at least for a time, able to resist this amyloid toxicity, says Gandy. This happens through a system where the brain compensates, engaging other, new and more parts of its structure to perform a task which once took a localized part of the brain. 

Researchers are now looking for more hallmarks of resilience against the amyloid toxicity of Alzheimer’s disease. For example, imaging studies show evidence that the hippocampus in individuals who are able to resist the disease is generally larger, says Troncoso. Larger brain cells in some of those without dementia also signals a potential source of resiliency, says Gandy.

Short of an outright cure, building resiliency might eventually lead to therapies that delay the onset of dementia. "If we can identify what are the mechanisms to do that, it may contribute to prevent or to alleviate the disease," says Gandy.

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

This prophetic 1997 Jeff Bezos interview explains the genius behind Amazon

Jeff Bezos, the founder of Amazon.com, explains his plan for success.

Technology & Innovation
  • Jeff Bezos had a clear vision for Amazon.com from the start.
  • He saw the innovative potential of the online marketplace.
  • Bezos explains why books, in particular, make for a perfect item to sell on the internet.
Keep reading Show less
Promotional photo of Lena Headey as Cersei Lannister on Game of Thrones
Surprising Science
  • It's commonly thought that the suppression of female sexuality is perpetuated by either men or women.
  • In a new study, researchers used economics games to observe how both genders treat sexually-available women.
  • The results suggests that both sexes punish female promiscuity, though for different reasons and different levels of intensity.
Keep reading Show less

TESS telescope has found eight new planets, six supernovae

It has found several bizarre planets outside of our solar system.

NASA/Kim Shiflett
Surprising Science
  • The Kepler program closed down in August, 2018, after nine and a half years of observing the universe.
  • Picking up where it left off, the Transiting Exoplanet Survey Satellite (TESS) has already found eight planets, three of which scientists are very excited about, and six supernovae.
  • In many ways, TESS is already outperforming Kepler, and researchers expect it to find more than 20,000 exoplanets over its lifespan.
Keep reading Show less