NEUROBIOLOGY OF ADOLESCENT

TOBACCO/NICOTINE USE DISORDERSKARA S. BAGOT, MDASSISTANT PROFESSOR

ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI

Nicotine and the adolescent brain

Yuan et al., 2015

MATURATION

THIS LECTURE COVERS

•INTRODUCTION TO REGIONS & TERMS

•NORMAL ADOLESCENT BRAIN DEVELOPMENT

•THE ADDICTED BRAIN

•NEUROBIOLOGICAL CONSEQUENCES

•SUMMARY

ADOLESCENCE = KEY FOR BRAIN MATURATION

NEUROSYSTEMS KEY TO DRUG EFFECTS

SUBCORTICAL STRUCTURESD

ennison et al., 2013

Nucleus accumbens (NAc): reward, euphoria, craving

Pallidum: (ventral) reward/pleasure

Hippocampus: learning, memory, stress

Thalamus: habits, perseveration

Amygdala: emotional/social processing, conditioned response to cues, associate rewards in the environment, hedonic processing

Ventral tegmental area (VTA): reward, motivation, cognition-origin of the dopaminergic cell bodies of the mesocorticolimbic dopamine system 

Caudate Putamen

CORTICAL STRUCTURES – EXECUTIVE FUNCTION

• ATTENTION, INHIBITION, COG CONFLICT RESOLUTION, RISKY DECISION-MAKING

• ANTERIOR CINGULATE CORTEX (ACC) – REWARD, IMPULSE CONTROL

• ORBITOFRONTAL CORTEX (OFC) – SENSORY INTEGRATION, DECISION-MAKING

• ACC & OCC…• RECIPROCALLY CONNECTED

• KEY NODES OF MESOCORTICAL DOPAMINE CIRCUITS

• DORSOLATERAL PREFRONTAL CORTEX (DLPFC) – ABSTRACT REASONING, INHIBITION, WORKING MEMORY, COGNITIVE FLEXIBILITY

CORTICAL STRUCTURES - SMOKERS

• ACC – ENHANCED ACTIVATION 🡪 DIFFICULTY RESISTING CUE-INDUCED CRAVING

• OFC – GENERATING OUTCOME EXPECTANCIES THAT GUIDE DECISION-MAKING

• DEFICIENCY ~ IMPULSIVITY AND DISINHIBITION

• ACC + OFC + DLPFC • CONTROL THE URGE TO SMOKE

• ACTIVATION ~ CRAVING

NEUROTRANSMITTERS KEY TO DRUG EFFECTS

• DOPAMINE (DA): SALIENCE, REWARD, PLEASURE

• OPIOID PEPTIDES: ANALGESIC, REWARD

• SEROTONIN (5-HT): MOOD

• NOREPINEPHRINE (NE): AROUSAL MOOD, SENSORY PROCESSING

• GABA: INHIBITORY; ANXIETY, MEMORY, ANESTHESIA • GLUTAMATE (GLU): EXCITATORY; COGNITION, LEARNING, MEMORY

• CORTICOTROPIN-RELEASING FACTOR (CRF): RELEASE OF PITUITARY GLAND HORMONES 🡪 ACTIVATE HPA AXIS 🡪 STRESS

• ACETYLCHOLINE (ACH): MOOD, AROUSAL

• CANNABINOIDS: COGNITION, MEMORY, MOVEMENT

REWARD CIRCUITRY

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