Researchers have created the most extensive map of gene activity found in the human prefrontal cortex to date. This particular brain region plays a vital role in functions like planning, decision-making, and regulating emotions and behavior. The map utilizes sequencing data from over six million individual cells sourced from nearly 1,500 people, providing valuable insights for studying neurodegenerative and psychiatric diseases more comprehensively.
The findings have been released in a collection of eight studies, which feature three papers published in the journal Nature.
Zhichao Miao, a computational biologist from the Guangzhou National Laboratory in China, commented on the impressive scale of the research. He noted that single-cell studies of the human brain had often involved relatively small groups of individuals, but this large-scale approach opens up new avenues for inquiry.
Focus on the Brain’s Planning Center
Panos Roussos, the director of the Center for Disease Neurogenomics at the Icahn School of Medicine at Mount Sinai in New York City, who contributed to all eight papers, explained that this extensive work began back in 2019. The initiative, known as the PsychAD Consortium and funded by the NIH, aims to link aspects of genetic variation, aging, and disease to alterations in specific brain cells.
The prefrontal cortex was the focal point of their studies, Roussos explained, due to its essential functions in working memory and ‘executive function,’ which includes planning and multitasking. He also mentioned that disruptions in a particular subregion—called the dorsolateral prefrontal cortex—are associated with several psychiatric disorders and types of dementia.
For their research, the team examined brain tissue from nearly 1,500 donors, who had passed away, ranging in age from infants to an individual who was 108 years old. These participants had diverse ancestries and included both neurotypical individuals and those diagnosed with one of eight brain disorders, such as Alzheimer’s disease, Parkinson’s disease, and bipolar disorder.
Through a method known as single-cell RNA sequencing, the researchers analyzed RNA transcripts within individual brain cells at the time of sampling, providing a detailed view of each cell’s status and functions.
This approach allowed the research team to record gene activity in more than 6.3 million individual brain cells, including neurons, immune cells, and vascular cells.
According to Roussos, studying the same brain region under varied conditions allows researchers to make more consistent comparisons, thereby linking their findings to existing genetic and molecular studies. He emphasized that while this research offers significant insights into brain disease, understanding the full picture will require exploring additional brain regions.
Study of Lifespan Changes
The researchers kicked off their investigation with a foundational study that looked at how the human dorsolateral prefrontal cortex evolves throughout a person’s life. They analyzed healthy brains from individuals aged less than one to 97 years. They identified three distinct stages of cortical development, which included a rapid remodeling phase in early life, a stable phase during mid-life, and another remodeling phase starting around age 65. The team observed different patterns of gene activity regarding various cell types, illustrating changes related to early brain development and late-life modifications associated with immune cell activity and the brain’s daily rhythms.
