The pleasure chemical?
Dopamine is often hailed as the neurochemical that mediates pleasure. The truth is, dopamine plays more of a role in “surprise” pleasure, or unexpected pleasure. This could be situations such as running into a friend or getting surprised with your favorite meal. Even if something good is going to happen, dopamine will play less of a role in mediating pleasure since it is predicted. It plays a role in addiction as well. It is released when one sees paraphernalia as a predicted feedback response. For example, a heroin addict may have learned to associate a needle with the high. When the drug doesn’t deliver what is expected, negative results ensue. This suggests that dopamine plays a role moreso with desire than pleasure. One generalization of dopamine’s roles involve salience, which tells when something demands attention. If a loud noise appears out of silence, dopamine will be released.
However, this is oversimplifying things. Some roles of dopamine include:
- Movement: It plays a role in smooth and controlled movements.
- Circadian rhythm: It suppresses melatonin in the morning to wake you up and can incite its release later in the day.
- Focus and attention: It may be responsible for determining what information to keep in one’s short term memory.
- Nausea: It controls nausea and vomiting by acting as a suppressant to prevent it.
- Cognition: It regulates the flow of information from other parts of the brain.
- Social function: Low levels are associated with social anxiety; high levels are associated with extreme sociability and sexual activity.
- Lactation: Stimulates lactation (some antipsychotics, which affect dopamine, can cause lactation even in men).
- Pain: It plays a role in processing pain in different parts of the central nervous system, including the spinal cord and thalamus.