The Causes of Anxiety

Last week, we read a paper published in Nature entitled "Amygdala circuitry mediating reversible and bidirectional control of anxiety" by Tye et al. I must confess that I understood little to none of the paper upon reading it the first time. After discussing the paper as a group, I believe that I have somewhat of a better understanding, although I would not take my word on this interpretation.

Anxiety and fear are two closely related responses, although fear, I believe, is better understood. This experiment was looking at the neural pathways that control anxiety in the amygdala.
So for part of the experiment, mice were injected with a virus that affected their basolateral amygdala, and then a light was shone onto certain parts of the amygdala to induce an anxious reaction. Once the neurons were unstimulated by the light, then the anxious reaction stopped.

The anxious reactions were tested by comparing the amount of time a mouse spent on a "maze" with no sides (so the mouse could easily fall off) versus the amount of time the mouse spent in the rest of the maze that had sides. The other test was an "open field test" where the mouse was in a big room with walls and the time was compared of how long the mouse spent around the outside of the room versus the how long the mouse was in the middle of the room. I believe another test they performed was with the light in the room on versus off for both the open field test and the maze. (The light on and off might have just been referring to the stimulation of the amygdala using light, I wasn't entire sure about this).

These tests made a lot of sense to me since mice are nocturnal, prey creatures. As a mouse, you don't want to be seen, you prefer corners and places with shadow where you can hide, and you don't like light, that exposes you.

From what I could tell, this experiment was highly successful in showing which neural pathways are associated with anxiety. This will be highly useful in the discovery of new ways to treat anxiety-like disorders.