Despite the fact that non-human primates and humans have quite different physical characteristics, a recent study suggests that their brains may be remarkably similar. Nevertheless, even minor adjustments can have a significant impact on psychological and developmental issues.
Researchers can examine disturbances in the development of the human brain by comprehending the molecular variations that set them apart. Researchers from the University of Wisconsin-Madison, led by neuroscience professor Andre Sousa, have recently published a study in the journal Science that examines the differences and similarities in prefrontal cortex cells between humans and non-human primates like chimpanzees, Rhesus macaques, and marmosets. The prefrontal cortex is the frontmost part of the brain and is important for higher cognitive functions.
The cellular variations between these species may shed light on key moments in their evolutionary history and how those variations may be related to human illnesses like autism and intellectual impairments. Sousa, a postdoctoral researcher at Yale University who researches the developmental biology of the brain at the Waisman Center at the University of Wisconsin–Madison, chose to begin by examining and classifying the cells in the prefrontal cortex.
“The dorsolateral prefrontal cortex is being profiled because it is particularly fascinating. Only primates have access to this cortical region. Other species don’t have it, “Says Sousa. “It has been linked to a number of high-level cognitive processes, including working memory. Additionally, it has been linked to a number of neuropsychiatric diseases. So, we made the decision to conduct this research to learn more about the distinctive features of the human brain in this area.”
More than 600,000 prefrontal cortex cells from tissue samples of chimpanzees, marmosets, macaques, and humans were genetically analyzed by Sousa and his team. They used that information to classify the cells into different categories and identify the variations among species in comparable cells. It was not surprising that the majority of the cells were very similar.
Because these species have evolved quite closely, the majority of the cells are actually quite similar, according to Sousa.
In the prefrontal cortex, Sousa and his team discovered five cell types that weren’t present in all four of the species. Additionally, they discovered variety among populations of cells that are identical across species as well as variations in the abundance of particular cell types. The distinctions between chimpanzees and humans appear to be enormous, ranging from their physical attributes to the extent of their mental capacities. However, at the cellular and genetic level, at least in the prefrontal cortex, there are many parallels and few differences.
“We are very interested in learning what makes the human brain special in our lab. Evidently, at least among primates, most of it is the same between this study and our earlier research, “Says Sousa.
The researchers’ little differences might be the first step in identifying some of those particular components, and this knowledge might provide new details about development and developmental diseases at the molecular level.
According to Sousa, “We want to know what transpired following the evolutionary divide between humans and other primates.” “The theory states that when one or more genes undergo a mutation, the functions of those genes are somewhat altered. However, if these genes are important for brain development, how would it alter the neural circuitry and their physiological characteristics, for instance, how many of a particular cell are formed, or how cells connect to one another? We are interested in knowing how these variations result in variations in the brain, which ultimately result in variations we can see in adulthood.”
The findings of the study were made in adult brains, which have undergone a significant amount of development. This suggests that the disparities might be developing as the brain grows. The researchers’ next step is to examine brain tissue samples from growing children and broaden their focus of inquiry outside the prefrontal cortex in order to maybe determine where and when these disparities originate. It is hoped that this knowledge will result in a more solid groundwork for developmental disease research.
“We have exceptional abilities, don’t we? We are researching everything from the universe to life itself. When you look around, this is very unique “says Sousa, whose group includes undergraduates Ashwin Debnath and Cade Hottman, graduate students Ryan Risgaards and Zachary Gomez-Sanchez, and research intern Danielle Schmidt. “If we possess these special skills, something in the brain must be responsible, right? We are quite curious to learn what it is in the brain that makes it possible for us to perform all of that.”
