Back to David's theory of evolution: brain problems (Evolution)

by David Turell @, Thursday, July 02, 2020, 01:21 (43 days ago) @ David Turell

Folding may go OK but there can be misfolding in the embryo:

https://cosmosmagazine.com/science/biology/understanding-how-brains-fold-and-misfold/?u...

"Australian and Swiss researchers say they have new clues to how a baby’s brain folds as it develops in the womb, a process critical to healthy brain function.

"Misfolding is linked with neurological conditions such as autism, anorexia, epilepsy and schizophrenia, but scientists do not fully understand what drives the folding process and why it sometimes goes wrong.

***

"Writing in the journal Cerebral Cortex, they report finding differences in both genetic expression and neuron shape during the folding process.

***

"The researchers say previous studies have focussed on white matter or looked at animals with smooth brains rather than folded ones, largely overlooking grey matter. Grey matter is made up of neuron bodies and their connecting arms; white matter comprises the neurons’ long nerve fibres and their protective layer of fat.

"The latest evidence suggests grey matter in the developing brain expands faster than white matter, creating mechanical instability that leads to brain folding. The resulting “hill” and “valley” folds follow a similar pattern in all folded brains of the same species.

"Tolcos and colleagues investigated the genetic and microstructural differences in future grey matter, the cortical plate, in the parts of the brain just beneath the “hills” and “valleys”. These areas were analysed at three points of development: when the brain was smooth, semi-folded and fully folded.

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“'We found some genes have higher expression in regions that fold outward and lower expression in regions that fold inwards. Other genes reverse this pattern,” says RMIT’s Sebastian Quezada Rojas.

“'Together, these genetic expression patterns might explain why the cortical folding pattern is so consistent between individuals of the same species.”

"These genetic differences are also correlated with changes in grey matter neurons, with the study finding variations in the number of arms – or dendrites – that neurons grow in these regions during the folding process.

“'We believe the regions that fold outward and inward are programmed to behave differently, and the shape of the neurons affects the way these areas fold,” Quezada Rojas says."

Comment: this is just one area in the embryo where mistakes can occur. As a cardiologist in training I learned about congenital heart defects. Luckily those can be surgically corrected. I can accept a God who can't stop these errors. It is interesting that dhw can't.


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