Featured Research

from universities, journals, and other organizations

Game Of Two Halves Leads To Brain Asymmetry

Date:
January 20, 2009
Source:
Wellcome Trust
Summary:
A tug-of-war between the two sides of the brain causes it to become asymmetrical, according to research published in the journal Neuron. Asymmetry in the brain is thought to be important to enable the two hemispheres to specialize and operate more efficiently.

Zebrafish brain.
Credit: Image courtesy of University College London

A tug-of-war between the two sides of the brain causes it to become asymmetrical, according to research published in the journal Neuron January 14. Asymmetry in the brain is thought to be important to enable the two hemispheres to specialise and operate more efficiently.

Left-right asymmetry is present in the brains of most animals and is first evident at the time of early brain development. However, until now, scientists did not know the mechanisms that bring it about. Now, in a study funded primarily by the Wellcome Trust, researchers have shown that a competition between the two sides causes this asymmetry.

By studying brain development in zebrafish, PhD student Jenny Regan and her colleagues in Professor Stephen Wilson's team at UCL (University College London) have shown that a protein known as Fgf8 acts as a magnet to attract nerve cells to one side of the brain. .

"Fgf8 is found in both sides of the brain, leading to a 'tug-of-war' competition between the two sides to attract the migrating group of nerve cells," says Dr Regan. "This isn't a fair fight, however – Fgf8 on the left-hand side has an ally to help it win the battle."

A second protein, known as Nodal, is present only on the left and teams up with Fgf8 to attract the group of nerve cells, triggering a cascade of events that lead to asymmetric development of the brain, with neurons on the left making different connections to those on the right. The combined action of Fgf8 and Nodal ensures that when the asymmetry develops, it is usually in the same direction – this helps to explain why there is consistent handedness between individuals. Nodal is known to also play a role in other areas of the body where asymmetry occurs, such as the heart and positioning of internal organs.

If Nodal is inhibited, the competition is fairer and the group of nerve cells has an equal probability of migrating to the right or left side, but a bias in the direction of migration can be restored by adding extra Fgf8 to one side of the brain.

"Brain asymmetry is essential for proper brain function," explains Professor Wilson. "It allows the two sides of the brain to become specialised, increasing its processing capacity and avoiding situations of conflict where both sides of the brain try to take charge.

"For example, faced with a predator, an animal would not want both sides of the brain to try to drive the escape as this might lead to conflict over which direction to turn. Instead, the animal might keep watch more with one eye (and consequently one half of the brain) and so each side of the brain might be dominant for particular activities."

Previous studies have shown that rearing chickens in the dark makes their brains less asymmetric. The chicks can still peck for food and watch out for predators, but only if doing one of these tasks at a time. When they try to do both, they are less efficient than fully asymmetric animals in which one eye specialises for one task and the other eye for the other task.

In humans, people with schizophrenia have disrupted brain asymmetries but as yet, it is not clear if there is a causal link between the asymmetry and schizophrenia.

"The direction and handedness that brain asymmetry takes is not critical for survival, but the strong bias towards one direction may be to ensure that all members of a population have consistent behaviours," adds Professor Wilson. "This may be very important for social animals, such as humans and schooling fish."

 


Story Source:

The above story is based on materials provided by Wellcome Trust. Note: Materials may be edited for content and length.


Cite This Page:

Wellcome Trust. "Game Of Two Halves Leads To Brain Asymmetry." ScienceDaily. ScienceDaily, 20 January 2009. <www.sciencedaily.com/releases/2009/01/090114124113.htm>.
Wellcome Trust. (2009, January 20). Game Of Two Halves Leads To Brain Asymmetry. ScienceDaily. Retrieved April 21, 2014 from www.sciencedaily.com/releases/2009/01/090114124113.htm
Wellcome Trust. "Game Of Two Halves Leads To Brain Asymmetry." ScienceDaily. www.sciencedaily.com/releases/2009/01/090114124113.htm (accessed April 21, 2014).

Share This



More Mind & Brain News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Study On Artists' Brain Shows They're 'Structurally Unique'

Study On Artists' Brain Shows They're 'Structurally Unique'

Newsy (Apr. 17, 2014) — The brains of artists aren't really left-brain or right-brain, but rather have extra neural matter in visual and motor control areas. Video provided by Newsy
Powered by NewsLook.com
Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) — A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Are School Dress Codes Too Strict?

Are School Dress Codes Too Strict?

AP (Apr. 16, 2014) — Pushing the limits on style and self-expression is a rite of passage for teens and even younger kids. How far should schools go with their dress codes? The courts have sided with schools in an era when school safety is paramount. (April 16) Video provided by AP
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) — A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins