Functional Neuroanatomy of Addiction Flashcards
Define addiction, abuse, dependence, withdrawal, tolerance, and cross-tolerance.
Addiction: Chronic, progressive behavioral disorder whose central feature is compulsive drug use despite adverse consequences. Abuse: Maladaptive use over 12+ months that leads to impaired functioning. Dependence: Abuse + withdrawal, tolerance, or a pattern of compulsive use. Withdrawal: Physical or psychological symptoms after the reduction or cessation of use. Tolerance: Need for increased amounts to achieve the same positive effects. Cross-Tolerance: Development of tolerance to one substance because of using another.
Where does dopamine originate? Where does it project to? What are the significance roles of these circuits?
Dopamine cell bodies are in the Ventral Tegmental Area. Project to the Nucleus Accumbens (reward) and the Prefrontal Cortex (executive control).
What 4 areas of the prefrontal cortex are important? What do they do?
DLPFC: Statistical/Cross-Benefit Analysis (“Top down control center). VMPFC: Assigns emotional valence. OFC: Impulse prevention. ACC: Vigilance.
What is the basic effects of drugs in creating addictive behavior?
Increase the limbic reward pathway by enhancing DA release, enhancing DA effects in the NA, &/or producing effects similar to DA. Chronic use sustains this increased limbic function and decreases PFC function.
Describe the limbic circuit. What happens to this in addiction?
This circuit uses DA. VTA supplies DA to NA. Amygdala assigns emotional value and acts at the VTA and NA. All of these pathways are excessive in addictive behaviors.
Describe the cortical control circuit. What happens to this in addiction?
This circuit uses GLU. The OFC and DLPFC project to the NA & the VMPFC, which also projects to the NA. The OFC should suppress addictive behavior, the DLPFC should calculate risk/benefit ratio of addictive behavior, and the VMPFC should assign positive feelings to not doing addictive behavior. These are likely to be deficient in addictive patients: Less active (less GLU), atrophy.
What is a goal of psychotherapy?
Strengthen the cortical control centers (PFC) in order to “reign” in the limbic system.