The nucleus accumbens is found in the basal forebrain situated between the C-shaped caudate and the putamen.
The nucleus accumbens is a pleasure center of the brain and is considered a reward pathway within the brain. When we do anything that we consider rewarding, we activate dopamine neurons in the brain. This in turn causes an increase in dopamine levels in the nucleus accumbens. Thus, the nucleus accumbens becomes an important part of a major dopaminergic pathway in the brain, stimulated during rewarding experiences.
Sometimes pain or discord in relationships play off between nucleus accumbens and amygdala, the pain center. In fact, dopamine levels rise anytime we experience something that we judge as either positive or negative.
In this sense, fear can be related to the experience of pleasure. On one end of the C-shaped caudate is the nucleus accumbens, which is a pleasure center. And at the other end is the amygdala, the pain or fear center, and they’re really close together. Pleasure excites the nucleus accumbens. But when it and the amygdala fire at same time, intense pleasure is experienced.
To sum up, the nucleus accumbens is an important brain area that responds to rewarding environmental stimuli, both positive and negative.