Mesocorticolimbic Dopamine Pathway
[Page 2086]Addiction is a disease characterized by the compulsion to use psychoactive substances (including alcohol) despite negative consequences. There are numerous biological, social, and psychological factors that predispose an individual to addiction. The mesocorticolimbic (MCL) pathway is the neural system most closely associated with addiction. It comprises neurons in the midbrain region, specifically the ventral tegmental area (VTA), that project to the following structures (overview of structural roles is in parentheses):
- Striatum (executive function, craving)
- Nucleus accumbens (NAc) (motivation, pleasure, reward, reinforcement)
- Ventral pallidum (output for limbic signals, reward, and motivation)
- Medial and orbital prefrontal cortex (foresight and planning)
- Amygdala (fear response)
The VTA neurons release the neurotransmitter dopamine (DA) at the above sites, causing a feeling of pleasure or reward at the NAc. Over time, this changes the DA release ...