Chinese and French scientists have developed an extremely detailed blueprint of the crab-eating macaque’s claustrum, an elusive brain region believed to play a role in consciousness.
The detailed map of connections between nerve cells in the macaque claustrum and the rest of the brain could help us understand how this region and its different cell types play a role in cognitive functions, such as memory integration and abstract thinking.
The team also revealed significant differences in the structure and cell types of macaque and rodent claustrums, which could provide clues to help investigate the evolutionary mechanism behind consciousness.
Do you have questions about the biggest topics and trends from around the world? Get the answers with SCMP Knowledge, our new platform of curated content with explainers, FAQs, analyses and infographics brought to you by our award-winning team.
“A single-cell spatial transcriptome atlas and a whole-brain connectivity map of macaque claustrum are generated,” the team said in a paper published in the peer-reviewed journal Cell on April 3.
The claustrum is a thin sheet of neurons – nerve cells that send messages around the body – and supporting cells in the brain which connect to the cerebral cortex as well as subcortical regions of the brain, like the hippocampus.
Research into the brain region has revealed that it plays a role in brain functions such as sleep regulation, depression, behavioural engagement, cognitive control and consciousness.
There is still no scientific consensus about how consciousness is generated and why human awareness differs from other animals, though this ability must come from some action in the brain.
While the claustrum is known to orchestrate brain functions via connections with numerous brain regions, its molecular and cellular organisation have been poorly understood.
The researchers from BGI-Research, the Chinese Academy of Sciences (CAS) and the Claude Bernard University Lyon 1 in France sequenced more than 227,000 claustral cells from the brains of crab-eating macaques, also known as cynomolgus monkeys.
By analysing RNA, or the cell messengers that carry instructions from DNA for the synthesis of proteins, they built a transcriptome atlas that provides information on active genes.
The extensive research conducted by the team led to several discoveries about the macaque claustrum, including the identification of 48 cell types and four distinct zones of neurons that preferentially connect to specific brain regions.
It was determined that local claustral zones connect to functionally related cortical and subcortical areas, which means specific populations of claustral neurons are specialised for different types of information.
They also found that the macaque claustral neurons were similar to those in the insular cortex, which suggests the main role of the claustrum may act as a hub to control information and connections across the brain.
When comparing the claustrum of macaques to those of marmosets and mice, the scientists found there were macaque-specific cell types present. This means that during the evolutionary process, the macaque claustrum developed distinct cell types to suit specific brain functions. This may shed insight into how unique adaptations contribute to consciousness.
“Together, these findings suggest that there are specific claustral adaptations in different species,” the team said in the paper.
BGI said the findings could open new avenues for studying the emergence of cognition and consciousness in primates, which could also offer a perspective on the evolution of human consciousness.
It also held promise for helping better understand neurological disorders, and could help develop therapeutic strategies to modulate cognitive processing, the institution said.
The team said further study on the macaque claustrum was needed, as their study could be limited by their methods of defining cell types and connectivity.
The full data set on the macaque claustrum developed by the team has been made publicly available online.
More from South China Morning Post:
- Stroke survivor speaks again with help of an experimental brain-computer implant
- Longevity wellness gyms can help extend health spans so you live longer in good shape
- US decouples from China in war on cancer, denying access to research databanks
- China advances in brain-computer interface technology, aiming for US$900 per procedure
- How does the human brain work? Chinese team’s ‘groundbreaking’ study offers clues
For the latest news from the South China Morning Post download our mobile app. Copyright 2025.
