Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Building a bigger brain

08.01.2019

A gene, found only in humans and active in the cerebral cortex, can enlarge the ferret brain

The human brain owes its characteristic wrinkled appearance to its outer layer, the cerebral cortex. During human evolution, the neocortex, the evolutionarily youngest part of the cerebral cortex, expanded dramatically and had to fold into wrinkles to fit inside the restricted space of the skull.


The picture shows the developing ferret brain. Magenta marks glial cells and clearly shows the outer contour of the brain. The green area consists of neurons that contain ARHGAP11B.

Kalebic / Gilardi / MPI-CBG

The human neocortex supports advanced cognitive skills such as reasoning and language. But how did the human neocortex become so big? The answer may lie in genes that are unique to humans, such as ARHGAP11B. Researchers at the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Dresden found that this human-specific gene, when introduced into the developing brain of ferrets, can cause an enlargement of their neocortex.

ARHGAP11B causes neural progenitor cells, which are cells that produce neurons, to make more of themselves for a longer period of time. The result is an expanded neocortex. The researchers published their findings in the journal eLife.

The human neocortex is roughly three times bigger than that of our closest relatives, the chimpanzees, and is the seat of many of the higher cognitive functions that are unique to humans, such as our speech or the ability to learn. A key question for scientists is how in human evolution the neocortex became so big.

In a 2015 study, the team around Wieland Huttner, research group leader at the MPI-CBG, found that under the influence of the human-specific gene ARHGAP11B, mice produced much more neural progenitor cells and could even undergo folding of their normally unfolded neocortex. The results suggested that the gene ARHGAP11B plays a key role in the evolutionary expansion of the human neocortex.

There are two types of neural progenitors in the mammalian neocortex: apical and basal. A subtype of the latter, called basal radial glial cells, are driving neocortex growth in human development. Unfortunately, mice have very few of them, which makes mice unsuitable to test whether the human-specific gene ARHGAP11B – via its effects on basal radial glial cells – can indeed cause an enlargement of the neocortex.

A team of researchers from the research group of Wieland Huttner now investigated what ARHGAP11B would bring about in a ferret brain. Ferrets have a larger neocortex than mice and possess more basal radial glial cells. The first author of the study, Nereo Kalebic, explains what he was able to observe:

“In ferrets, ARHGAP11B noticeably increased the number of basal radial glial cells. It also extended the time window during which the basal radial glial cells produced neurons. As a result, these ferret brains contained more neurons and thus had a bigger neocortex.” These results suggest that ARHGAP11B may have a similar role in the developing human brain. This study also provides the first evidence of a human-specific gene increasing the number of basal radial glial cells in a folded neocortex.

Wieland Huttner, who supervised the study, gives an outlook: “Further experiments need to be done to determine whether the ferrets with a larger neocortex also have enhanced cognitive abilities. If they do, testing these animals may provide insights into human cognition.”

Wissenschaftliche Ansprechpartner:

Wieland Huttner
+49 (0) 351 210 1500
huttner@mpi-cbg.de

Nereo Kalebic
+49 (0) 351 210 2516
kalebic@mpi-cbg.de

Originalpublikation:

Nereo Kalebic, Carlotta Gilardi, Mareike Albert, Takashi Namba, Katherine R Long, Milos Kostic, Barbara Langen, Wieland B Huttner: “Human-specific ARHGAP11B induces hallmarks of neocortical expansion in developing ferret neocortex” eLife, 28. November, 2018.

Katrin Boes | Max-Planck-Institut für molekulare Zellbiologie und Genetik
Further information:
https://www.mpi-cbg.de/de/home/

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Programming light on a chip

Research opens doors in photonic quantum information processing, optical signal processing and microwave photonics

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new integrated photonics platform that can...

Im Focus: Physicists uncover new competing state of matter in superconducting material

A team of experimentalists at the U.S. Department of Energy's Ames Laboratory and theoreticians at University of Alabama Birmingham discovered a remarkably long-lived new state of matter in an iron pnictide superconductor, which reveals a laser-induced formation of collective behaviors that compete with superconductivity.

"Superconductivity is a strange state of matter, in which the pairing of electrons makes them move faster," said Jigang Wang, Ames Laboratory physicist and...

Im Focus: Tumors backfire on chemotherapy

Some patients with breast cancer receive chemotherapy before the tumor is removed with surgery. This approach, called 'neoadjuvant' therapy, helps to reduce the size of the tumor to facilitate breast-conserving surgery, and can even eradicate the tumor, leaving few or no cancerous cells for the surgeon to remove. In those cases, the patients are very likely to remain cancer-free for life after surgery.

But not all tumors shrink under chemotherapy. If the tumor resists neoadjuvant therapy, there can be a higher risk of developing metastatic disease, meaning...

Im Focus: One of the world's fastest cameras films motion of electrons

Kiel research team examines ultrafast conversion of light energy in a solid

During the conversion of light into electricity, such as in solar cells, a large part of the input light energy is lost. This is due to the behaviour of...

Im Focus: First detection of rain over the ocean by navigation satellites

In order to analyse climate change or provide information about natural hazards, it is important to gather knowledge about the rain. Better knowledge of precipitation and its distribution could, for example, help protect against river flooding. A new approach uses, for the first time, information contained in radar signals from navigation satellites to detect rain over the sea. The technology could help to monitor atmospheric precipitation better than before.

In order to analyse climate change or provide information on natural hazards, for example, it is important for researchers to gather knowledge about rain.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

How herpesviruses shape the immune system

09.01.2019 | Health and Medicine

Stanford researchers create a wireless, battery-free, biodegradable blood flow sensor

09.01.2019 | Interdisciplinary Research

Research explains public resistance to vaccination

09.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>