New York (PTI): Scientists in the United States have identified brain cells linked to fear, paving the way for a more effective treatment of post-traumatic stress and other anxiety disorders.

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.

The latest path breaking research, which was published online by journal 'Nature' on July 9, was carried out by Professor Denis Par at New Jersey's Centre for Molecular and Behavioural Neuroscience of Rutgers University in Newark.

Looking into amygdala and how its activity impacts behaviour, Professor Par identified a critical component of the amygdalas neural network normally involved in the extinction, or elimination, of fear memories, the Science Daily online reported.

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.

Research has shown 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).

Combat soldiers returning from action have increasingly shown anxiety disorders, which can lead to myriad problems that hinder daily life or ruin it altogether such as drug abuse, alcoholism, marital problems, unemployment and suicide. According to one estimate, nearly 15 percent of American troops returning from Iraq and Afghanistan develop PTSD.