The 20th century was a watershed in neurobiology; in particular, the years 1990 to 2000 were the “decade of the brain.” To understand the neurobiology of anxiety comprehensively would require an intensive familiarity with neurochemistry and neuroanatomy. The reader might enjoy taking a look at Joseph LeDoux’s The Emotional Brain, in which a wonderful illustration of the emotional circuitry of the brain becomes intimately connected to the way we perceive fear.
LeDoux details the different inputs, conscious and unconscious, from an immediate sensory input (sight and smell) to higher thinking (“this is a stick, not a snake”) and examines their creation, neuroanatomically, of our emotional and bodily flight-or-fight response. Several basic things show up time and again in today’s research, all of which make our work very exciting and gratifying in 2005. We know certain areas of the brain axis are highly involved in the creation of anxiety. In particular, a region called the amygdala responds to potentially dangerous stimuli by chemically arousing the body to respond immediately.
When danger is perceived to be close at hand, the amygdala’s connections to the rest of the body bypass any areas of higher thought, which make our bodies respond in a fight-or-flight way. This circuitry (called the limbic system,as in liminal, or threshold between emotion and thought), in turn, makes the memory of the particular trauma or perceived trauma indelible and codes the input of this memory on file for use in future dangerous situation assessments. We know that chronic stress is associated with an increase in cortisol,which can result in the creation of illness or have all kinds of deleterious long-term effects on the body, making the expense of long-term anxiety quite costly to the body (in extreme panic, cortisol can flood the body and create a shock similar to surgical shock, or sudden death).
Panic disorder and posttraumatic stress disorders are the best studied in the neurobiological realm; however, many exciting areas remain for future discovery with respect to imaging and understanding the roles of all of the different neurotransmitters which the brain uses in its regulation of anxiety. Major neurotrans-mitters that receive frequent mention include cortisol, epinephrine, norepinephrine, -aminobutyric acid (GABA), and serotonin. It is just as important to remember that literally hundreds of unidentified neu-rotransmitters make up the complexity of our thinking and feelings, as well as their connections to the rest of the body. While we may know something about the actions of any given neurotransmitter, it is still too early to know how those interactions may cascade or interface downstream with the entire “soup” of our brain chemistry.
Rick’s comments: In the answer to Question 10, it is mentioned that one successful style of dealing with anxiety is humor. I’ve per-formed and written some comedy, so this seems to apply. I bring this up a question later because my first reaction to LeDoux’s example of higher thinking (“this is a stick, not a snake”) was: “wasn’t that the mistake that Yul Brenner made in the movie The Ten Commandments?” When I am doing something that causes me anxiety (writing, for instance) I am more likely to think in humorous or offbeat ways. When, as a youngster, some friends and I walked on a frozen lake, which terrified me, I was actually coming up with one joke after another to hide my fear. (The next time you see someone standing on a frozen lake doing a comedy routine, it’s probably me.) Now that’s neurobiology!