The cognitive abilities of the human brain increased during evolution
Scientists have reached an important stage in understanding the complex mechanisms that control the development of the cerebral cortex, the part of the brain that plays a key role in attention, perception, awareness, thinking, memory, language, and consciousness.
The brain is made up of billions of neurons that communicate with each other, forming many connections and synapses. The cerebral cortex (plural cortices) is the outer layer of nerve tissue in the brains of humans and other mammals. Previous studies have shown that mammalian brain development is accompanied by a progressive expansion of the cerebral cortex.
The deliberate study, led by Prof Lars Alan Larsen and Prof Soren Tvorup Christensen of the University of Copenhagen (UCPH) in Denmark, was published in Nature Communications.
The team began a genetic analysis of a large family that would have a child with primary microcephaly, a rare congenital brain disorder characterized by the decreased size of the cerebral cortex and varying degrees of cognitive dysfunction.
The researchers found that the children carried mutations in both copies of the RRP7A gene. Using stem cells and zebra cultures as body models, RRP7A plays an important role in brain stem cells to reproduce and form new neurons. This process is very complex and minor disturbances can have serious repercussions, which may explain why mutations affect the brain and not other tissues and organs.
“Our results are surprising because they reveal a previously unknown mechanism involved in brain development. It also underscores the value of research into rare diseases, which are important for patients and families affected by the disease. Also important for society is new knowledge of human biology,” he said. Prof. Larsen, Department of Molecular and Cellular Medicine.
In addition, the researchers found that mutations in RRP7A affect a function of the so-called primary cilia, single copies that are projected onto the cell surface as antenna-like structures to register environmental signals and control the formation of new neurons in the developing brain.
“Our results open up new ways to understand how the development of primary cilia control and how certain mutations in these antenna-like structures affect tissue and organ formation during development. To this end, we have initiated a number of studies.
Understanding the mechanism RRP7A regulates ciliary signals to control formation and the organization of neurons in the brain, and how defects in those signals can lead to brain malformations and cognitive impairment, said Prof. Christensen of the Department of Biology.”