Navigation Links
Rutgers research identifies brain cells related to fear
Date:7/10/2008

NEWARK, NJ The National Institute of Mental Health estimates that in any given year, about 40 million adults (18 or older) will suffer from some form of anxiety disorder, including debilitating conditions such as phobias, panic disorders and post-traumatic stress disorder (PTSD). It is estimated that nearly 15 percent of U.S. soldiers returning from Iraq and Afghanistan develop PTSD, underscoring the urgency to develop better treatment strategies for anxiety disorders. These disorders can lead to myriad problems that hinder daily life or ruin it altogether such as drug abuse, alcoholism, marital problems, unemployment and suicide.

Functional imaging studies in combat veterans have revealed that the amygdala, a cerebral structure of the temporal lobe known to play a key role in fear and anxiety, is hyperactive in PTSD subjects. Potentially paving the way for more effective treatments of anxiety disorders, a recent Nature report by Denis Par, professor at the Center for Molecular and Behavioral Neuroscience at Rutgers University in Newark, has identified a critical component of the amygdala's neural network normally involved in the extinction, or elimination, of fear memories. Par's laboratory studies the amygdala and how its activity impacts behavior. His research was published online by Nature on July 9, 2008 and is scheduled to appear in the print edition later in July.

Earlier research has revealed that in animals and humans, the amygdala is involved in the expression of innate fear responses, such as the fear of snakes, along with the formation of new fear memories as a result of experience, such as learning to fear the sound of a siren that predicts an air raid.

In the laboratory, the circuits underlying learned fear are typically studied using an experimental paradigm called Pavlovian fear conditioning. In this research model on rats, a neutral stimulus such as the sound of a tone elicited a fear response in the rats after they heard it paired with an noxious or unpleasant stimulus, such as a shock to the feet. However, this conditioned fear response was diminished with repetition of the neutral stimulus in the absence of the noxious stimulus. This phenomenon is known as extinction. This approach is similar to that used to treat human phobias, where the subject is presented with the feared object in the absence of danger.

Behavioral studies have demonstrated, however, that extinction training does not completely abolish the initial fear memory, but rather leads to the formation of a new memory that inhibits conditioned fear responses at the level of the amygdala. As such, fear responses can be expressed again when the conditioned stimulus is presented in a context other than the one where extinction training took place.

For example, suppose a rat is trained for extinction in a grey box smelling of roses, and later hears the tone again in a different box, with a different smell and appearance. The rat will show no evidence of having been trained for extinction. The tone will evoke as much fear as if the rat had not been trained for extinction.

"Extinction memory will only be expressed if tested in the same environment where the extinction training occurred, implying that extinction does not erase the initial fear memory but only suppresses it in a context-specific manner," notes Par.

Importantly, it has been found that people with anxiety disorders exhibit an "extinction deficit," or a failure to "forget." However, until recently, the mechanisms of extinction have remained unknown.

As reported by Nature, Par has found that clusters of amygdala cells, known as the intercalated (ITC) neurons, play a key role in extinction. His findings indicate that ITC cells inhibit amygdala outputs to the brain stem structures that generate fear responses. Indeed, Par and his collaborators have shown that when ITC cells are destroyed with a targeted toxin in rats, extinction memory is impeded, mimicking the behavior seen in PTSD.

The significance of this finding derives from earlier results suggesting that PTSD reflects an extinction deficit and that the amygdala is hyperactive in this disorder. As a result, it might be possible to compensate for this abnormality and facilitate extinction with pharmacological interventions that enhance the excitability of ITC cells to inhibit amygdala outputs.


'/>"/>

Contact: Helen Paxton
paxton@andromeda.rutgers.edu
973-353-5262
Rutgers University
Source:Eurekalert

Related medicine news :

1. NYU, Rutgers study shows how using mental strategies can alter the brains reward circuitry
2. Rutgers scientist receives prestigious Young Investigator Award
3. Rutgers researchers show how the brain can protect against cancer
4. The Healthcare Foundation of NJ awards grant to Rutgers College of Nursings Rachel Jones
5. 2 Rutgers College of Nursing Ph.D students to receive FNSNA Fellowships
6. Rutgers College of Nursings Linda Flynn to receive N.J. Governors Nursing Merit Award
7. Rutgers research partner Stemcyte, Inc., expands to New Jersey
8. The Zonta Club of Essex County honors Rutgers College of Nursings Rachel Jones
9. Julia Quinlan to present awards at a conference hosted by Rutgers College of Nursing
10. Rutgers researchers unlock mysteries of vitamin A metabolism during embryonic development
11. NJSNA honors Rutgers College of Nursings Linda Flynn for excellence in research
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/28/2017)... ... March 28, 2017 , ... Award-winning medical group Allied ... as new board chair for Orange County health care system CalOptima Friday. CalOptima ... soon-to-be former chair Mark Refowitz’s term, which runs through June 30 of this ...
(Date:3/28/2017)... ... March 28, 2017 , ... With less than 10,000 ... access to quality care can be limited while the desire to conquer breakouts and ... prescription acne care for every customer online, today released its inaugural survey on the ...
(Date:3/28/2017)... St. Petersburg Florida (PRWEB) , ... March 28, 2017 , ... ... U.S. Marine Corp to raise money to for the Toys for Tots Literacy Campaign ... a federal budget in excess of $70 billion, the U.S. ranks at number 14 ...
(Date:3/28/2017)... , ... March 28, 2017 , ... ... be offered by the American Association of Integrative Medicine and available for application ... providers at the AutismOne 2017 Conference in Colorado Springs. , Ed Arranga, president ...
(Date:3/28/2017)... ... March 28, 2017 , ... The Lice Treatment Center® ... March 13-16, was a busy spot this year. Liz Solovay and Adrian Picheny, ... preventing outbreaks among camp communities during the upcoming 2017 camping season. “Lice infestations ...
Breaking Medicine News(10 mins):
(Date:3/28/2017)... , March 28, 2017  Medeon Biodesign, Inc., ... company, is pleased to announce that the Company ... of Panther Orthopedics, Inc., a San ... fixation solutions for orthopedic extremity applications.  ... expand rapidly, primarily due to procedure volume growth, ...
(Date:3/28/2017)... 2017 Summary ... as a Key Component of Multichannel Marketing" provides ... landscape in the digital age. While the ... medical advancements, it has been much slower to ... on traditional channels and methods. However, the decreasing ...
(Date:3/28/2017)... and TORONTO , March 28, ... leading full service medical device development firm, announced ... visionary Toronto -based medical device industrial ... better serve medtech companies throughout North America ... and experienced medical device talent spanning the design, engineering, ...
Breaking Medicine Technology: