The Evolution of Human Brain Set It Up for Failure

Recent research has uncovered a link between the evolution of the human brain and the increased susceptibility to Alzheimer's disease. While apes, including our closest relatives the chimpanzees, do not develop Alzheimer's in the same way humans do, there are distinct patterns in the accumulation of toxic proteins in human brains compared to other species.

The Swedish geneticist Svante Pääbo's groundbreaking work, which sequenced the Neanderthal genome, revealed that brain activity in humans is different from other primates, indicating a link between human brain evolution and Alzheimer's disease. A study by Thomas Arendt and his team found nearly 300 genes with altered activity levels in the brains of Alzheimer's patients, suggesting that these genes played a crucial role in the unique evolution of the human brain.

Duke University researchers discovered that genes involved in amyloid protein production, which forms the main plaques in Alzheimer's disease, have undergone significant changes due to human evolution. In China and the United Kingdom, regulatory DNA associated with Alzheimer's risk has also been traced back to periods of rapid brain evolution.

The MD Anderson Cancer Center found uniquely human genes that interfere with a protein called REST, which normally protects against Alzheimer's. These findings collectively suggest that the genetic changes responsible for the cognitive leap that set humans apart may also have made our brains more vulnerable to Alzheimer's disease.

The parietal lobes, which are crucial for abstract cognition and self-awareness, have expanded significantly in humans compared to nonhuman primates. These regions are also among the first to be affected by Alzheimer's, indicating that the very traits that make our brains distinct may also be contributing to our susceptibility to the disease.