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Prefrontal Cortex Holds the Key to Conquering Fear
> 1/25/2007 2:25:06 PM

The effective management of fear and its resulting stresses is essential to the daily lives of all humans. From our very beginnings, we've used both inherent and conditioned fear as central mechanisms of survival and self-preservation in the face of potential threats. For many, the obstacles posed by excessive fear can prove too great, crippling other central faculties and interfering with daily life. Scientists have long been interested in studying the initial physical fear response and the subsequent intellectual and emotional consideration given the stimuli in question (a process that often happens during flight).

When a human or animal encounters an object or entity that may be seen as dangerous, the eyes and other sensory systems send neural messages directly to the amygdala, a small walnut-shaped structure located in the lower brain. This action kickstarts the process of releasing glucose, heightening physical awareness to prepare the body for a quick response. All of these internal functions are unconscious, but after this initial stimulation, the brain more closely evaluates the threat to better gauge an appropriate response. Scientists generally believe that the prefrontal cortex, a cognitive center in the mammalian forebrain, plays an important role in this transition from stimuli to action, and recent research elaborates on the theory, reinforcing the crucial steps in the fear/stress response process.

In a newly published study, researchers in Puerto Rico seem to have isolated the area of the brain responsible for learned fear responses to stimuli among rats. By interfering with the functions of this isolated area, they all but eliminated the fight-or-flight mechanism in instances of learned fear. The rats in the survey were exposed to a pre-recorded tone after which painful electrical shocks were administered. Of course, the rats quickly learned to associate the tone with the shock and soon responded in fear to the sound itself, spending most of the tone's duration frozen in place. In a second group, researchers chemically inhibited the prefrontal cortex and observed that the rats, for the most part, no longer displayed the fear response when confronted with the tone. Their findings imply that the prefrontal cortex is responsible for creating learned conditional fear, and that without it the animals lost their apprehension regarding elements they'd been conditioned to fear.

The learned fear response should not be confused with that of genetic or innate fear. Researchers noted that rats dosed with the chemicals used to control the prefrontal cortex still displayed the same fearful reactions to more traditional threats-large animals, wide open spaces, etc., so these threats are too immediate and pre-programmed to necessitate a response from the prefrontal cortex. The stimuli-processing-reaction series is, of course, too complex to sum up in one series of studies, but the obvious implication is that scientists may soon develop a chemical combination with the potential to neutralize the prefrontal cortex and suppress learned fear in humans.