While the physical differences between non-human primates and humans are stark, a new study shows that their brains can be quite similar. And small changes can make significant differences in developmental and psychiatric disorders.
Understanding the molecular differences that set the human brain apart could help researchers study disruptions in brain development. Madison – A new study recently published in Science, led by a research team including Andre Sousa, professor of neuroscience at the University of Wisconsin-Madison (UW-Madison), examines the differences and similarities between cells in the prefrontal cortex of humans and non-human primates such as chimpanzees, Indian monkeys, and marmoset monkeys. This region which is based at the front of the brain plays a major role in higher cognitive functions.
Cellular differences between these species may shed light on the steps in their evolution and how these differences may be involved in human disorders such as autism and intellectual disabilities. Sousa, who studies developmental brain biology at the UW-Madison Waisman Center, decided to start researching and classifying cells in the prefrontal cortex with a lab at Yale University, where he was a postdoctoral research fellow.
“We are profiling the dorsolateral prefrontal cortex because it has interesting properties. This cortical region is only found in primates. It is not found in other species,” Sousa explains. “It is associated with several functions related to higher consciousness, such as memory. It is also associated with some neuropsychiatric disorders.
The researchers, who collected the genetic information of more than 600,000 cells from tissue samples, say that since the species studied are closely related in evolutionary terms, most cells are very similar.
Sousa and other contributors discovered five cell types in the prefrontal cortex that were not found in any of the four species. While the researchers found many differences in specific cell types, they also found variations among similar cell populations across species. When a chimpanzee is compared to a human, the differences – ranging from their physical appearance to the capabilities of their brains – seem enormous. But at the cellular and genetic level, at least in the prefrontal cortex, there are many similarities and few differences.