As it is known, humans are seen as the smartest creatures in the world. Maybe we are not completely “smart”, but when it comes to brain development we are at least the most advanced creatures. That’s why scientists really want to know why.
Many people, of course, call the answer to this question evolution, but the real answer to why our brains evolve differently from those of other great apes and chimpanzees has long been seen as a mystery. A new study published in the journal Cell provides the first real insights into how the growth of the human brain differs from our closest mammalian relatives.
What makes us human?
According to the research, people can do many things, largely depending on the physical size of our brains. Our brain organs are much larger than chimpanzees and monkeys, and the large number of neurons that our brain has compared to primates is what helps to separate us.
By growing small samples of brain tissue in the laboratory, the researchers were able to detect a significant difference in the early development of the human brain compared to chimpanzees and monkeys. According to the findings, while humans and primates first develop, their brains are constructed from cells known as neural progenitor cells.
These are stem-like cells that multiply over and over again and eventually form neurons. The equation is simple, scientists say, because more progenitor cells mean more neurons further down the road, and it turns out that human progenitor cells, monkeys and chimpanzees behave differently from progenitor cells.
While observing the progenitor cell proliferation behavior in primates, the researchers discovered that the cells continued to multiply at a high rate for roughly five days before ripening and slowing down. This is considered much longer than mice, where cells appear to mature within hours.
The extended time frame means primates have more brain power and larger brain organs, the study said. However, human ancestor cells take this to the next level.
Also, the study reveals that human progenitor cells continue to multiply for a full week before transitioning. Since the proliferation of cells is an exponential event, it is stated that replicating for an extra two days means much more cells and ultimately neurons in humans.
The lead author of the study, Dr. Madeline Lancaster says about the study;
“We found that a delayed change in the shape of cells in the early brain is sufficient to change the course of development and helps determine the number of neurons made. It is noteworthy that a relatively simple evolutionary change in cell shape could have major consequences for brain evolution. As far as I can remember, I feel we really learned something fundamental about the questions I was dealing with – what makes us human? “