In addition to neurotransmitters, other neurochemicals can also have dramatic effects. For example, brain-derived neurotrophic factor (BDNF) aids in the growth of new neurons and overall brain health.
Stress biases the brain toward any of our old habits over new actions. The dorsal striatum says, “Let’s do it this way, because we’ve always done it this way.” And the prefrontal cortex says, “But that won’t help us get where we want to go.” Meanwhile, the nucleus accumbens says, “Ooh, that cupcake looks delicious.”
The prefrontal cortex.
Each quadrant of the prefrontal cortex is primarily responsible for a different group of functions. The medial parts are more self- focused, while the lateral parts are more focused on the outside world. Along the vertical dimension, the ventral parts are more emotional, while the dorsal parts are focused more on thinking. Thus the primary distinction in the prefrontal cortex is between dorsolateral and ventromedial (in other words, the top-side versus the bottom-middle). The ventromedial prefrontal cortex is the more self-focused, emotional part of the prefrontal cortex and is particularly important in motivation and controlling your impulses. Calling it “emotional” might seem confusing, since I’ve said that the limbic system (rather than the prefrontal cortex) is the emotional part of the brain, but think of it this way: the ventromedial prefrontal cortex thinks about emotions, while the limbic system feels them. In contrast, the dorsolateral prefrontal cortex thinks more about the outside world and is thus more responsible for planning and problem solving.
The "feeling brain" aka limbic system
It is primarily composed of four regions: the hypothalamus , the amygdala , the hippocampus , and the cingulate cortex . The hypothalamus controls stress. The amygdala is the key to reducing anxiety, fear, and other negative emotions. The hippocampus is responsible for creating long-term memories, and because its neurons are very sensitive to stress, it often acts as the canary in the coal mine of depression. Lastly, the cingulate cortex controls focus and attention, which is of huge importance in depression, because what you focus on, whether by automatic.
In addition to the prefrontal cortex and limbic system, two other regions play important roles in depression: the striatum and the insula . Both are closely connected to the fronto- limbic system, and in fact, scientists sometimes lump parts of them into the limbic system.
Many many suggestions backed up by research:
Think of happy memories. Happy memories boost serotonin in the anterior cingulate (chapter 8). Try to think of one happy memory before you go to sleep— write it in a journal or just reflect on it.