Featured Research

from universities, journals, and other organizations

Depression Traced To Overactive Brain Circuit

Date:
August 4, 2004
Source:
NIH / National Institute Of Mental Health
Summary:
A brain imaging study by the NIH's National Institute of Mental Health (NIMH) has found that an emotion-regulating brain circuit is overactive in people prone to depression — even when they are not depressed.

Areas that show over-activity following tryptophan depletion in depression patients in remission — and thought to reflect a trait dysfunction — include emotion regulating circuitry involving the anterior cingulate, thalamus, ventral striatum and orbitofrontal cortex. (Source: NIMH Mood and Anxiety Disorders Program 2004)

A brain imaging study by the NIH's National Institute of Mental Health (NIMH) has found that an emotion-regulating brain circuit is overactive in people prone to depression — even when they are not depressed. Researchers discovered the abnormality in brains of those whose depressions relapsed when a key brain chemical messenger was experimentally reduced. Even when in remission, most subjects with a history of mood disorder experienced a temporary recurrence of symptoms when their brains were experimentally sapped of tryptophan, the chemical precursor of serotonin, the neurotransmitter that is boosted by antidepressants.

Neither a placebo procedure in patients nor tryptophan depletion in healthy volunteers triggered the mood and brain activity changes. Brain scans revealed that a key emotion-processing circuit was overactive only in patients in remission — whether or not they had re-experienced symptoms — and not in controls. Since the abnormal activity did not reflect mood state, the finding suggests that tryptophan depletion unmasks an inborn trait associated with depression.

Alexander Neumeister, M.D., Dennis Charney, M.D., Wayne Drevets, M.D., NIMH Mood and Anxiety Disorders Program, and colleagues, report on their positron emission tomography (PET) scan study in the August 2004 Archives of General Psychiatry.

The NIMH researchers and others had previously shown that omitting tryptophan from a cocktail of several other essential amino acids washes out the precursor chemical from the blood and brain, depleting serotonin and often triggering symptoms in people with a history of depression — and even in healthy people from depression-prone families. This added to evidence that a genetic predisposition that renders some people vulnerable to inadequate serotonin activity may be at the root of the mood disorder.

The researchers scanned subjects after their blood tryptophan levels were reduced by about three-fourths, using a radioactive tracer (a form of glucose, the brain's fuel) which reveals where the brain is active during a particular experimental condition.

They randomly gave 27 unmedicated depressed patients-in-remission and 19 controls either pills containing seven essential amino acids, such as lysine and valine, or identical-looking placebo pills. Subjects received either the active pills or placebos in repeated trials over several days in a blind, crossover design.

Sixteen (59 percent) of the patients experienced a transient return of symptoms under tryptophan depletion; their mood lifted to normal by the next day. Compared to controls, the patients showed increased brain activity in a circuit coursing through the front and center of the brain (orbitofrontal cortex, thalamus, anterior cingulate, and ventral striatum) — areas involved in regulating emotions and motivation that have been implicated in previous studies of depression. Whereas previous studies interpreted the circuit activation as a transient, mood-dependent phenomenon, the new evidence suggests that circuit over-activation is likely an underlying vulnerability trait, say the researchers.

Because of its ability to unmask what appears to be a trait marker for major depressive disorder, the researchers suggest that tryptophan depletion may be a useful tool for studying the genetic basis of depression.

"Since brain function appears to be disregulated even when patients are in remission, they need to continue long-term treatment beyond the symptomatic phase of their illness," noted Neumeister, who recently moved to the Yale University psychiatry department.

Also participating in the research were: Drs. Allison Nugent, Tracy Waldeck, Omer Bonne, Earl Bain and Marilla Geraci, David Luckenbaugh, NIMH; Dr. Markus Schwarz, Munich University Hospital of Psychiatry, Dr. Peter Herscovitch, NIH Clinical Center PET Department.

NIMH is part of the National Institutes of Health (NIH), the Federal Government's primary agency for biomedical and behavioral research. NIH is a component of the U.S. Department of Health and Human Services.


Story Source:

The above story is based on materials provided by NIH / National Institute Of Mental Health. Note: Materials may be edited for content and length.


Cite This Page:

NIH / National Institute Of Mental Health. "Depression Traced To Overactive Brain Circuit." ScienceDaily. ScienceDaily, 4 August 2004. <www.sciencedaily.com/releases/2004/08/040804090102.htm>.
NIH / National Institute Of Mental Health. (2004, August 4). Depression Traced To Overactive Brain Circuit. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2004/08/040804090102.htm
NIH / National Institute Of Mental Health. "Depression Traced To Overactive Brain Circuit." ScienceDaily. www.sciencedaily.com/releases/2004/08/040804090102.htm (accessed July 29, 2014).

Share This




More Mind & Brain News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

It's Not Just Facebook: OKCupid Experiments With Users Too

It's Not Just Facebook: OKCupid Experiments With Users Too

Newsy (July 29, 2014) If you've been looking for love online, there's a chance somebody has been looking at how you're looking. Video provided by Newsy
Powered by NewsLook.com
How Your Face Can Leave A Good Or Bad First Impression

How Your Face Can Leave A Good Or Bad First Impression

Newsy (July 29, 2014) Researchers have found certain facial features can make us seem more attractive or trustworthy. Video provided by Newsy
Powered by NewsLook.com
Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com
University Quiz Implies Atheists Are Smarter Than Christians

University Quiz Implies Atheists Are Smarter Than Christians

Newsy (July 25, 2014) An online quiz from a required course at Ohio State is making waves for suggesting atheists are inherently smarter than Christians. 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