Synaptic failure is an important issue when it comes to brain diseases that get worse over time, like Alzheimer’s and Parkinson’s. It can lead to big problems with thinking and daily activities. Here are some key points to understand:

1. Commonness: About 50% of people with neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, have lost some synapses early on in their illness.

2. Causes:

   • Amyloid-beta Buildup: In Alzheimer’s, problems with synapses are linked to the build-up of a substance called amyloid-beta. Even a small increase in amyloid levels can reduce the number of synapses by as much as 30%.
   • Tau Protein Issues: Another problem comes from a protein called tau. When this protein becomes too active, it can form tangles in the brain, which harm the connections between brain cells.

3. Thinking Problems: Losing synapses is connected to having a harder time thinking. Research shows that if there’s a 1% drop in synapse numbers, it can lead to a 0.5-point drop in how well someone scores on thinking tests.

4. Treatment Goals: Helping synapses work better again is a key part of creating new treatments. Some therapies aimed at restoring synapse function have shown good promise in lab tests, helping to improve issues by up to 40%.

By understanding these points, we can see how important maintaining synaptic health is for brain function and the development of future treatments.