Fear is a "gut" feeling

                As of late, neuroscientists have been conducting more research on threats and fear. These studies will provide insight on how diseases such as post-traumatic stress disorder and certain phobias must be dealt with. Although more information is needed to develop cures, these studies are a step in the right direction and will serve as a base to the progressive research of the future in this field.

In their study, Intuitively detecting what is hidden within a visual mask, neuroscientists Anne Cleary, Anthony Ryals, and Jason Nomi prove that humans are capable of “Recognition Without Identification" (RWI), more commonly known as “gut feelings” or instinct. These gut feelings arise in situations where an individual does not have sufficient information. Thus, he or she must rely on instinct to act appropriately.

                Their study focuses largely on the evolutionary implications of RWI. Their research suggests that RWI is an evolutionary product, and they test this by having the research participants’ view threatening images. The images were obscured with Photoshop and the participants wore masks to hinder their identification. The participants were able to recognize over 32% of the threatening images, versus only 1% of non-threatening ones. This highlights that this trait is evolutionary since it has been favorable for people to recognize threats in the past, to help them survive those threats. Their traits would be passed down (including RWI abilities) while the genes of those that did not survive would eventually be eradicated from the gene pool.

                Recently, a research team led by Urs Meyer, a staff member of the Laboratory of Physiology & Behaviour at ETH Zurich, has discovered where these gut feelings in response to threats arise from. It is not only a product of the brain as expected, but the stomach sends signals to the brain in a situation with a threat present. The brain will read these signals and will then translate them into fear, so that the body may act accordingly. The vagus nerve sends signals to both organs in each direction. The nerves extending from the brain to the internal organs are termed the efferent nerves, and those from the stomach to the brain are the afferent nerves. When the afferent nerves were cut in rats, they responded with less fear to threats.

This study demonstrates that the feelings felt by humans in the former study, was induced by the vagus nerve sending signals from the stomach to the brain. Without this nerve, humans would be less adapted to recognize threats and would be less efficient in responding in a logical manner. However, they would still be able to recognize learned threats from the past, since cutting the afferent nerves did not affect learned fear. When the rats in Meyer’s study were conditioned to link a sound to an unpleasant experience, the vagus nerve played no role and they still experienced fear with cut afferent nerves.

                It is now clear that the stomach, not only the brain, plays a significant role in how we respond to fear. However, although it is clear that there are signals sent to the brain from the stomach, it is still not clear what those signals are. Scientists are still trying to determine the role of the vagus nerve and the dialogue between the brain and the body. More information on fear and how it functions in the body will provide insight on how we must handle diseases such as post-traumatic stress disorder and certain phobias. If they can learn that the situation is not threatening in actuality, they can overcome their phobia. Although these studies are a start, more information is needed.