Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neural connection keeps instincts in check

10.01.2017

EMBL scientists identify the physical connection through which the prefrontal cortex inhibits instinctive behavior

From fighting the urge to hit someone to resisting the temptation to run off stage instead of giving that public speech, we are often confronted with situations where we have to curb our instincts. Scientists at EMBL have traced exactly which neuronal projections prevent social animals like us from acting out such impulses. The study, published online today in Nature Neuroscience, could have implications for schizophrenia and mood disorders like depression.


The prefrontal cortex connects to a very specific region of the brainstem (the PAG) through prefrontal cortical neurons: those labeled in purple directly project to the PAG and control our instinctive behaviors.

Credit: EMBL/Livia Marrone

"Instincts like fear and sex are important, but you don't want to be acting on them all the time," says Cornelius Gross, who led the work at EMBL. "We need to be able to dynamically control our instinctive behaviours, depending on the situation."

The driver of our instincts is the brainstem - the region at the very base of your brain, just above the spinal chord. Scientists have known for some time that another brain region, the prefrontal cortex, plays a role in keeping those instincts in check [see box]. But exactly how the prefrontal cortex puts a break on the brainstem has remained unclear.

Now, Gross and colleagues have literally found the connection between prefrontal cortex and brainstem. The EMBL scientists teamed up with Tiago Branco's lab at MRC LMB, and traced connections between neurons in a mouse brain. They discovered that the prefrontal cortex makes prominent connections directly to the brainstem.

Gross and colleagues went on to confirm that this physical connection was the brake that inhibits instinctive behaviour. They found that in mice that have been repeatedly defeated by another mouse - the murine equivalent to being bullied - this connection weakens, and the mice act more scared. The scientists found that they could elicit those same fearful behaviours in mice that had never been bullied, simply by using drugs to block the connection between prefrontal cortex and brainstem.

These findings provide an anatomical explanation for why it's much easier to stop yourself from hitting someone than it is to stop yourself from feeling aggressive. The scientists found that the connection from the prefrontal cortex is to a very specific region of the brainstem, called the PAG, which is responsible for the acting out of our instincts. However, it doesn't affect the hypothalamus, the region that controls feelings and emotions. So the prefrontal cortex keeps behaviour in check, but doesn't affect the underlying instinctive feeling: it stops you from running off-stage, but doesn't abate the butterflies in your stomach.

The work has implications for schizophrenia and mood disorders such as depression, which have been linked to problems with prefrontal cortex function and maturation.

"One fascinating implication we're looking at now is that we know the pre-frontal cortex matures during adolescence. Kids are really bad at inhibiting their instincts; they don't have this control," says Gross, "so we're trying to figure out how this inhibition comes about, especially as many mental illnesses like mood disorders are typically adult-onset."

Tiago Branco is now at the Sainsbury Wellcome Centre.

Background information: from metal rods to Pac-man

Neuroscience textbooks have long carried the story of Phineas Gage. In 1848, while he was packing explosives into a rock to clear the way for a railroad, a premature explosion shot a metal rod through Gage's head. Remarkably, he survived. But his personality appears to have changed - although accounts and interpretations vary over what exactly the changes were, and how long they lasted. Nevertheless, Gage's case was instrumental in proving that there was a connection between brain and personality. Exactly which parts of Gage's brain were damaged has also been the subject of intense debate. The frontal lobes of his brain were certainly affected, and computer-based reconstructions of Gage's injury, as well as studies of other patients - injured in accidents or by stroke - have pointed to the prefrontal cortex as a likely seat for our inhibitions.

A study of people trying to avoid injury - albeit in a simulated environment - hinted at how that inhibition might come about. Looking at the brains of people as they played a Pac-man-like game in an MRI scanner, scientists found that while players were 'running away' from 'Pac-man', their pre-frontal cortex was active, but in the moments just before their character was eaten, players' pre-frontal cortex would shut down and a region of the brainstem called the PAG became active. This study suggested a link between those two brain regions, and inspired Gross and colleagues to investigate.

Media Contact

Isabelle Kling
isabelle.kling@embl.de
49-622-138-78355

 @EMBLorg

http://www.embl.org 

Isabelle Kling | EurekAlert!

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>