Featured Research

from universities, journals, and other organizations

Serotonin levels affect the brain's response to anger

Date:
September 15, 2011
Source:
University of Cambridge
Summary:
Fluctuations of serotonin levels in the brain, which often occur when someone hasn't eaten or is stressed, affects brain regions that enable people to regulate anger, new research has shown.

Fluctuations of serotonin levels in the brain, which often occur when someone hasn't eaten or is stressed, affects brain regions that enable people to regulate anger, new research from the University of Cambridge has shown.

Related Articles


Although reduced serotonin levels have previously been implicated in aggression, this is the first study which has shown how this chemical helps regulate behaviour in the brain as well as why some individuals may be more prone to aggression. The research findings were published September 15, in the journal Biological Psychiatry.

For the study, healthy volunteers' serotonin levels were altered by manipulating their diet. On the serotonin depletion day, they were given a mixture of amino acids that lacked tryptophan, the building block for serotonin. On the placebo day, they were given the same mixture but with a normal amount of tryptophan.

The researchers then scanned the volunteers' brains using functional magnetic resonance imaging (fMRI) as they viewed faces with angry, sad, and neutral expressions. Using the fMRI, they were able to measure how different brain regions reacted and communicated with one another when the volunteers viewed angry faces, as opposed to sad or neutral faces.

The research revealed that low brain serotonin made communications between specific brain regions of the emotional limbic system of the brain (a structure called the amygdala) and the frontal lobes weaker compared to those present under normal levels of serotonin. The findings suggest that when serotonin levels are low, it may be more difficult for the prefrontal cortex to control emotional responses to anger that are generated within the amygdala.

Using a personality questionnaire, they also determined which individuals have a natural tendency to behave aggressively. In these individuals, the communications between the amygdala and the prefrontal cortex was even weaker following serotonin depletion. 'Weak' communications means that it is more difficult for the prefrontal cortex to control the feelings of anger that are generated within the amygdala when the levels of serotonin are low. As a result, those individuals who might be predisposed to aggression were the most sensitive to changes in serotonin depletion.

Dr Molly Crockett, co-first author who worked on the research while a PhD student at Cambridge's Behavioural and Clinical Neuroscience Institute (and currently based at the University of Zurich) said: "We've known for decades that serotonin plays a key role in aggression, but it's only very recently that we've had the technology to look into the brain and examine just how serotonin helps us regulate our emotional impulses. By combining a long tradition in behavioral research with new technology, we were finally able to uncover a mechanism for how serotonin might influence aggression."

Dr Luca Passamonti, co-first author who worked on the research while a visiting scientist at the Cognition and Brain Sciences Unit of the Medical Research Council in Cambridge (and currently based at the Consiglio Nazionale delle Ricerche (CNR), Unitΰ di Ricerca Neuroimmagini, Catanzaro), said: "Although these results came from healthy volunteers, they are also relevant for a broad range of psychiatric disorders in which violence is a common problem. For example, these results may help to explain the brain mechanisms of a psychiatric disorder known as intermittent explosive disorder (IED). Individuals with IED typically show intense, extreme and uncontrollable outbursts of violence which may be triggered by cues of provocation such as a facial expression of anger.

"We are hopeful that our research will lead to improved diagnostics as well as better treatments for this and other conditions."

This study was supported by the James S. McDonnell Foundation


Story Source:

The above story is based on materials provided by University of Cambridge. The original story is licensed under a Creative Commons license. Note: Materials may be edited for content and length.


Journal Reference:

  1. Luca Passamonti, Molly J. Crockett, Annemieke M. Apergis-Schoute, Luke Clark, James B. Rowe, Andrew J. Calder, Trevor W. Robbins. Effects of Acute Tryptophan Depletion on Prefrontal-Amygdala Connectivity While Viewing Facial Signals of Aggression. Biological Psychiatry, 13 September 2011 DOI: 10.1016/j.biopsych.2011.07.033

Cite This Page:

University of Cambridge. "Serotonin levels affect the brain's response to anger." ScienceDaily. ScienceDaily, 15 September 2011. <www.sciencedaily.com/releases/2011/09/110915102917.htm>.
University of Cambridge. (2011, September 15). Serotonin levels affect the brain's response to anger. ScienceDaily. Retrieved March 6, 2015 from www.sciencedaily.com/releases/2011/09/110915102917.htm
University of Cambridge. "Serotonin levels affect the brain's response to anger." ScienceDaily. www.sciencedaily.com/releases/2011/09/110915102917.htm (accessed March 6, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, March 6, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Suicide Rates Up For Young Women In U.S.

Suicide Rates Up For Young Women In U.S.

Newsy (Mar. 6, 2015) — According to a report from the CDC, suicide rates among young women increased from 1994 to 2012 while rates among young men have decreased. Video provided by Newsy
Powered by NewsLook.com
Bupa Eyes India Healthcare Opportunities

Bupa Eyes India Healthcare Opportunities

Reuters - Business Video Online (Mar. 5, 2015) — Bupa is hoping to expand in India&apos;s fast-growing health insurance market, once a rule change on foreign investment is implemented. The British private healthcare group&apos;s CEO tells Grace Pascoe why it&apos;s so keen on the new opportunity. Video provided by Reuters
Powered by NewsLook.com
Liberia Releases Last Ebola Patient, But Threat Remains

Liberia Releases Last Ebola Patient, But Threat Remains

Newsy (Mar. 5, 2015) — Liberia&apos;s last Ebola patient has been released, and the country hasn&apos;t recorded a new case in a week. However, fears of another outbreak still exist. Video provided by Newsy
Powered by NewsLook.com
Doctor in Your Pocket Is Getting Smarter

Doctor in Your Pocket Is Getting Smarter

Reuters - Business Video Online (Mar. 5, 2015) — Mobile apps are turning smartphones into a personal doctors, with users able to measure heart rate, blood pressure and even blood sugar. But will it change our behaviour? Ivor Bennett reports from the Mobile World Congress in Barcelona. Video provided by Reuters
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:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

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