The limbic system is the part of the brain that regulates emotion and memory.
It is located in the midbrain, which, from an evolutionary perspective, is the second oldest part of the brain (the brain stem is the oldest part, and the cortex, that wrinkly part of the brain, is the newest part).
The midbrain is also sometimes called the reptilian brain because it is similar to the brain structure of reptiles, who do not have a cortex. The cortex grew around the midbrain and is what gives us our higher-order levels of thinking (processing math, reading, and so on).
Anxiety occurs in the midbrain, specifically in the limbic system. Therefore, the medications that target anxiety have some effect on the midbrain and the neurotransmitters there. We will review different neurotransmitters and how those medications affect them.