Addiction

Addiction

Chronic relapsing brain disorder characterized by compulsive drug seeking and use despite harmful consequences.

Substance Use Disorder (SUD)

Clinical disorder involving impaired control over substance use that causes significant impairment or distress.

Drug Reinforcement

Process by which a drug increases the likelihood of repeated use because of its rewarding effects.

Reward System

Brain network that reinforces behaviors necessary for survival and is hijacked by addictive drugs.

Mesolimbic Dopamine Pathway

Primary reward pathway connecting the VTA to the nucleus accumbens.

Ventral Tegmental Area (VTA)

Source of dopamine neurons involved in reward and reinforcement.

Nucleus Accumbens (NAc)

Brain region that mediates reward, motivation, and reinforcement.

Prefrontal Cortex (PFC)

Brain region involved in decision-making, impulse control, and inhibitory control over drug seeking.

Medial Prefrontal Cortex (mPFC)

Regulates executive control and suppresses compulsive drug-seeking behaviors.

Amygdala

Processes emotional learning and conditioned drug-associated cues.

Basolateral Amygdala (BLA)

Associates environmental cues with drug reward and relapse.

Hippocampus (HPC)

Encodes contextual memories associated with drug use.

Dorsal Hippocampus (dHPC)

Contributes to contextual learning and drug-associated memories.

Glutamatergic Neurons

Excitatory neurons that regulate reward learning and craving circuits.

Dopamine Neurons

Neurons that signal reward prediction and reinforcement.

Cannabinoid

Compound that activates cannabinoid receptors in the brain.

WIN 55,212-2

Potent synthetic cannabinoid receptor agonist commonly used in addiction research. :contentReference[oaicite:1]{index=1}

Self-Administration

Animal model in which animals voluntarily administer a drug to study reinforcing effects.

Operant Conditioning

Learning in which behavior is modified by its consequences, such as receiving a drug reward.

Fixed Ratio 1 (FR1)

Reinforcement schedule in which every response is rewarded.

Fixed Ratio 2 (FR2)

Reinforcement schedule in which every second response is rewarded.

Active Lever

Lever that delivers the drug during self-administration experiments.

Time-Out Period

Brief interval after drug delivery during which additional responses are not reinforced.

Extinction

Reduction of drug-seeking behavior when drug reinforcement is removed.

Reinstatement

Return of drug-seeking behavior after extinction due to cues, stress, or drug exposure.

Craving

Intense desire or urge to consume a drug.

Cue-Induced Craving

Craving triggered by environmental cues previously associated with drug use.

Drug-Associated Memory

Learned association between environmental cues and drug reward.

Addiction-Like Behavior

Collection of behaviors resembling human addiction observed in animal models.

Persistence to Respond

Continued drug seeking despite the absence of reinforcement. :contentReference[oaicite:2]{index=2}

Motivation

Willingness to work to obtain a drug reward. :contentReference[oaicite:3]{index=3}

Compulsivity

Continued drug use despite negative consequences. :contentReference[oaicite:4]{index=4}

Addiction-Like Criteria

Behavioral measures used to classify animals as addiction-prone. :contentReference[oaicite:5]{index=5}

75th Percentile Cutoff

Threshold used to classify animals as positive for addiction-like traits. :contentReference[oaicite:6]{index=6}

Reinforcement

Process that increases the probability of repeating a behavior.

Conditioning

Learning through associations between stimuli and rewards.

Reward Prediction

Error

Relapse

Return to drug use after abstinence.

Vulnerability

Predisposition to develop addiction due to genetic or environmental factors.

Resilience

Ability to resist developing addiction despite exposure.

Gene-Environment Interaction

Combined influence of genetics and environment on addiction risk.

Synaptic Plasticity

Long-lasting changes in synaptic strength that contribute to addiction.

Dopaminergic Signaling

Dopamine transmission involved in reinforcement and motivation.

Glutamatergic Signaling

Glutamate transmission involved in learning, memory, and relapse.

mPFC-NAc Projection

Prefrontal pathway that suppresses compulsive drug seeking; inhibition increases addiction vulnerability. :contentReference[oaicite:7]{index=7}

BLA-NAc Pathway

Projection involved in conditioned drug reward and addiction-like behaviors. :contentReference[oaicite:8]{index=8}

dHPC-NAc Pathway

Projection involved in contextual memory and reinforcement of drug seeking. :contentReference[oaicite:9]{index=9}

Optogenetics

Technique using light-sensitive proteins to control neuronal activity.

Chemogenetics

Method using engineered receptors activated by designer drugs to control neurons.

AAV

Vector commonly used to deliver genes into neurons for experimental manipulation.

Deschloroclozapine (DCZ)

Designer drug used to activate chemogenetic receptors. :contentReference[oaicite:10]{index=10}

qPCR

Molecular technique used to measure gene expression.

MicroRNA (miRNA)

Small non-coding RNA molecules that regulate gene expression.

Epigenetics

Heritable changes in gene expression without altering DNA sequence.

Sex Differences

Differences between males and females in addiction vulnerability and neurobiology.

Telescoping Effect

Phenomenon in which females progress from initial drug use to addiction more rapidly than males. :contentReference[oaicite:11]{index=11}

Female Vulnerability

Females show greater vulnerability to compulsive addiction-like behaviors than males. :contentReference[oaicite:12]{index=12}

Executive Control

Cognitive ability to inhibit inappropriate behaviors and impulses.

Conditioned Reinforcement

Drug-associated cues become reinforcing through learning.

Transcranial Magnetic Stimulation (TMS)

Non-invasive brain stimulation technique being investigated as a treatment for cannabis use disorder. :contentReference[oaicite:13]{index=13}

Cannabis Use Disorder

Substance use disorder characterized by problematic cannabis use causing impairment.