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 New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>