Happiness, sleep, learning, addiction, movement, eating, motivation, and pain. How are all of these seemingly different phenomena linked? The neurotransmitter, dopamine! There are actually 4 main dopamine pathways with different types of dopamine receptors in each, resulting in this neurotransmitter's wide influence on behavior. Read below to learn more about dopamine pathways, and like, comment on, or share this post to give me a mesolimbic dopamine boost! * * * 1. All 5 dopamine receptors are GCPRs (see post from 2/11/18 for a video). Receptors D1/5 are considered "D1-like" receptors, whereas D2-D4 receptors are considered "D2-like." There are different amounts across the 4 dopamine pathways (swipe for a diagram). * 2. Nigrostriatal – Originates in the substantia nigra. It is heavily involved in movement. Individuals with Parkinson's disease have a loss of dopamine neurons in this pathway, contributing to symptoms like tremors, rigidity, and poor balance. . * 3. Mesolimbic – Originates in the ventral tegmental area (VTA) and spreads to subcortical regions like the nucleus accumbens and amygdala. It is involved in reward seeking behaviors, including evaluation of an outcome’s desirability, motivation to do a behavior that will get you a desirable outcome (like praise), motivation to stop doing a behavior that will result in an undesirable outcome (like pain), learning the relationship between the behavior-outcome to guide future actions, and craving of desirable outcomes. Clinically, dysfunction is mostly associated with symptoms of addiction, depression, and schizophrenia. . * 4. Mesocortical – Also originates in the VTA and spreads to cortical regions, like the medial prefrontal cortex. It has a close association with the mesolimbic pathway, so is involved in similar functions and clinical conditions. . * 5. Tuberoinfundibular – Originates in the hypothalamus and projects to the pituitary gland. It is involved in regulation of prolactin, a hormone that controls breast milk production. Dysfunction is related to abnormal breast milk production, headaches, vision problems, and menstrual cycle changes.