Being A Chicken Is Achieved, Not Innate

You should know that those characters played by Bruce Willis or Van Damme have achieved their braveness, because they were born cowards, just as any of us.

Moreover, research made on rats not only showed this, but also found the part of the brain's cortex that controls the learned (not innate) fear behaviors. "The results suggest that hyperactivity in a region of the prefrontal cortex might contribute to disorders of learned fear in humans, such as post-traumatic stress disorder and other anxiety disorders," said authors Dr. Kevin A. Corcoran and Dr. Gregory Quirk, of the Ponce School of Medicine in Puerto Rico.

Scientists have long thought that the amygdala, found inside the brain, controls all our fear and emotional learning. But the new research involves the cortex - the outer brain zone - in the fear responses. "This is the first paper demonstrating that a region of the cortex is involved in learned fear but not in innate fear," says Dr. Markus Fendt, of the Novartis Institutes for Biomedical Research in Basel, Switzerland.

The researchers made rats associate a 30-second tone with a hit to the foot at the end of the tone. This provoked a fear reflex on rats: when hearing the same tone the next day, rats remained nearly 70 % of the time of the tone frozen, a typical fear reaction.

Other group of rats suffered a chemical blockage in the prelimbic cortex, near the front of the brain and the midline between the two hemispheres. These rodents expressed only 14 % the fear reactions.

But the rats' innate (natural) fears appeared not affected by blocking the prelimbic cortex; they displayed the freezing reaction when seeing a predator or being placed in a large open area as they did to hearing the tone.

The rats used in the experiment involving the prelimbic cortex were tested drug-free the next day. They displayed a normal fear response, thus suppressing the prelimbic cortex that did not impede them from learning to fear the tone. The prelimbic cortex is linked to the amygdala, and the team suspects that "by modulating amygdala activity, the prelimbic cortex is important for determining the circumstances in which it is appropriate to convey learned fears."

But the innate fear seems to have no cortex control. "Corcoran and Quirk's work raises the question of whether learned fear is more controllable--for example, by higher brain functions--than innate fear," says Fendt.