More on the brain’s default network:
The default network in the brain is considered a “second brain” because it turns on when the rest of the brain is at rest, and turns off when the rest of the brain is at work. Normally, that is. As people age, the default network is less and less capable of shutting down when the mind is concentrating on some difficult cognitive task as it would do in a younger adult’s brain. Since the default network uses 30% more resources than the rest of the brain, you can see how the resources available for cognitively challenging tasks decreases as we age.
In Alzheimer’s, you get the extreme case of this aging effect: the default network doesn’t shut down at all when it’s supposed to (same as in Schizophrenia–which is probably why they use antipsychotic drugs meant for Schizophrenia in Alzheimer’s patients) until that part of the brain eventually dies.
The default network is not very developed in children. It gets more active as we grow into adulthood. That makes me wonder if language is the software that runs the default network. Think about it: the default network is the part of the brain that sorts, categorizes, and edits/deletes memories, and language is the software that sorts, categorizes, and edits/deletes meaning. With language also comes prejudice, and prejudice does not exist in the very young. Also, in Alzheimer’s the default network eventually atrophies, and language ceases (just further argument that the default network is inextricably tied to language).
All of which brings me to the point of this post. Last week there were articles all over the news saying that having more than one language guards you against the worst of Alzheimer’s. Mom spoke four languages and fell prey to Alzheimer’s in her sixties–with no family history of early Alzheimer’s. Dad spoke three languages and ended up with Parkinson’s and dementia–particularly the loss of language.
Why did their brains conspire against them when they had all the tools (higher education, multiple languages) that should have kept them safe?
I’m thinking there has to be a powerful environmental factor in their cases. Was it the DDT that Dad sprayed all over the house every night when we went to bed (for the twelve years they lived in Bolivia)? Did the poison initiate something in their bodies way back then that resulted in brain damage?
If so, the only one of us eight kids that should be spared is the youngest. She was out of the picture during the DDT years. Yeeha.
Just mulling things over.