A new study identifies an immune brain cell that is unique to humans and is responsible for our superior cognitive abilities compared to other animals. However, what makes us special also makes us susceptible to neurological disorders such as schizophrenia, autism, and epilepsy.
Yale neuroscientists evaluated cells located in the dorsolateral prefrontal cortex, the region engaged in executive control tasks, which is shared by humans and monkeys, and refined the list to five cells found uniquely in the human brain, including microglia, an immune cell.
Microglia aids in brain maintenance rather than disease prevention and has a gene related to neuropsychiatric disorders that are absent in primates.
We can see the dorsolateral prefrontal cortex as the essential component of human identity, according to the study’s lead author Nenad Sestan, but we do not yet know what makes this unique to humans and distinguishes us from other monkey species.
The dorsolateral prefrontal cortex is responsible for switching and task-set reconfiguration, interference prevention, planning inhibition, and working memory.
Scientists hypothesize that the presence of microglia during adolescence has consequences for vulnerability to certain psychiatric diseases. Microglia are present throughout development and into adulthood.
According to the team, comparative investigations indicate that human brain development is unique.
Humans vary from other primates in that they maintain a fetal-like pace of brain mass growth throughout the first postnatal year, resulting in a comparatively large adult brain size.
However, they wished to discover hints as to what contributes to our superior cognitive abilities.
The scientists examined over 600,000 single-nucleus transcriptomes from the dorsolateral prefrontal cortex of adult humans, chimpanzees, macaques, and marmosets (dlPFC).
Thus, they were able to determine which cells are exclusive to each species.
‘Compared to other primate species, humans have a completely different environment and lifestyle, and glia cells, particularly microglia, are quite sensitive to these variations,’ Sestan added in a statement.
The microglia located in the human brain may reflect an immunological response to the surrounding environment.
Variations of the FOXP2 gene have been associated with verbal dyspraxia, a condition in which patients have trouble creating language or speech.
FOXP2 is also connected with neuropsychiatric disorders such as autism, schizophrenia, and epilepsy, according to other research.
This gene demonstrates primate-specific expression in a subset of excitatory neurons and human-specific expression in microglia, as discovered by Sestan and colleagues.
Shaojie Ma, a postdoctoral associate in Sestan’s group and co-lead author, stated in a release, ‘FOXP2 has fascinated scientists for decades, but we had no understanding of what makes it special in humans as opposed to other primate species.
We are ecstatic about the FOXP2 results since they offer up new avenues for the study of language and disorders.
