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Learn how to not be afraid:-

Why do some people have the ability to remain calm and relaxed even in the most cases of stress? New experiments in mice from Howard Hughes Medical Institute (HHMI) researchers and provide insight into how changes in the brain when animals learn to feel safe and secure in situations that usually makes them anxious.

HHMI investigator Eric R. Kandel and Daniela D. Polak tests conducted in rats conditioned to feel safe in stressful situations. Experiments have shown that mice that developed conditioned inhibition of fear, which Kandel calls "learned safety."
Behavioral changes observed in the mice frustrated concern in the most effective anti-depressant drugs such as Prozac, said Kandel, who is at Columbia University. "It's a bit like psychotherapy," he noted. "This shows that behavioral intervention works."

This research is reported in the October 9, 2008, in the journal Neuron. Kandel conducted the study with Pollak, who will soon leave the Kandel lab to assume a position in the Faculty of Medicine, University of Vienna.

In the new study is noteworthy because it reveals in detail how elegant behavioral conditioning can affect the brain. According to Kandel, knowing how behavioral intervention works at the molecular and cellular levels may be a way of attention to identifying new ways to treat depression and anxiety disorders.

Kandel, who trained as a psychiatrist, is intrigued by new discoveries. "I've always been interested in how the work of psychoanalysis," he said. "As the experience of learning, and there must be a biological basis in the brain."

Two types of fear, instinctive and learned, and have evolutionary roots, which is necessary to stay alive. But in some people, pathological forms can be learned from the fear that will lead to debilitating anxiety disorders, post-trauma, or depression. I learned safety, on the other hand, reduces chronic stress, one of the hallmarks of depression and other psychopathologies. "The ability to identify, develop and exploit conditions of safety and security is fundamental to survival and mental health," said Kandil, "but little is known of the neurobiology of these processes."

In previous research, Kandel to teach the group of mice to associate myself with a particular tone with protection from an impending averse event. Over time, the mice became conditioned to take advantage of sources of security and safety in their environments. In the new study nervousness, Pollack Kandel sought to know the characteristics of behavioral and molecular learned safety in mice.

In their experiments, mice were trained to associate safety or fear with specific auditory stimuli (t). The air of fear, coupled with the shock stimulus audio light on the mouse in the foot. Air safety, and auditory stimuli was not followed by shock. Experiments have shown that the safety-conditioned mice learned to associate the tone with the absence of danger and displayed less anxiety in the presence of this reference safety.

Transition to a stress test, Kandel team placed the safety-conditioned mice in a pool of water for a swim test. Forced swimming test is usually used by researchers to measure how antidepressant drugs affect the behavior of mice. "In this desperate situation it seems - in mice, where they have no option to escape from the water - they are beginning to show signs of behavioral despair better than drugs for depression. We found that mice trained for safety could be overcome by a sense of hopelessness in the swim test," explained Kandil. The impact of anti-depressants in the safety-conditioned mice was similar and comparable in size to the treatment with the drug fluoxetine (Prozac), Kandel noted.

Pollak and Kandel then looked at how learned safety influenced the development of newborn cells in the dentate gyrus, the structure is located in an area of the brain called the hippocampus. Dentate gyrus is worth mentioning because it is one of the few structures in the brain that generate new neurons - even in adult animals.

The researchers found that mice which had been conditioned for safety had a greater number of newborn cells in the dentate gyrus. When Kandel's team used radiation to blunt the birth of new cells in the dentate gyrus, they discovered that their interventions both slowed safety learning and stunted the effects of anti-depressants learned safety.

Pollak and Kandel also found that safety learning to accelerate the expression of brain-derived neurotrophic factor or BDNF in the dentate gyrus. BDNF is a growth factor that promotes growth and differentiation of new neurons and their connections.

Intriguingly, genetic analysis revealed in the amygdala in the brain and fear center, learned safety tunes the expression of key components of the nervous system, dopamine, and the neuropeptide. Both systems are believed to influence learning, mood, and cognition.

Kandel said his group was intrigued to find that learned safety did not affect serotonin, a neurotransmitter typically targeted anti-depressant drugs. I learned safety appears to influence the levels of both dopamine neurons and neuropeptide, which suggests new ways to develop drugs for depression, he said.

"They gave us many insights and led us to a number of potential targets for new drugs," Kandel explained, noting that there are already agents in development that affect the dopamine and neuropeptide pathways