What’s Up-The Neurobiology What’s Up-The Neurobiology of Learning and Adolescent of Learning and Adolescent Substance Abuse Substance Abuse Merrill Norton Pharm.D.,D. Ph., Merrill Norton Pharm.D.,D. Ph., NCAC II, CCS NCAC II, CCS Clinical Associate Professor Clinical Associate Professor University of Georgia University of Georgia College of Pharmacy College of Pharmacy Athens,Georgia 30602 Athens,Georgia 30602 706-542-5371 706-542-5371 [email protected][email protected]
Transcript
What’s Up-The Neurobiology of What’s Up-The Neurobiology of Learning and Adolescent Substance Learning and Adolescent Substance
AbuseAbuse
Merrill Norton Pharm.D.,D. Ph., NCAC II, CCSMerrill Norton Pharm.D.,D. Ph., NCAC II, CCS
Clinical Associate ProfessorClinical Associate Professor
““......relatively permanent changes in behavior relatively permanent changes in behavior produced by experienceproduced by experience””– Learning involves changes in the nervous Learning involves changes in the nervous
system produced by experiencessystem produced by experiences– Nervous system changes are physicalNervous system changes are physical– Learning allows us to adapt our behaviors to Learning allows us to adapt our behaviors to
the environment the environment – Learning involves interactions among the Learning involves interactions among the
motor, sensory, and memory systemsmotor, sensory, and memory systems
14.3
Forms of LearningForms of Learning
PerceptualPerceptual learning functions to identify objects learning functions to identify objects and situationsand situations
Stimulus-ResponseStimulus-Response learning involves making a learning involves making a response when a particular stimulus is presentresponse when a particular stimulus is present– Classical conditioningClassical conditioning– Operant ConditioningOperant Conditioning
MotorMotor learning involves forming new circuits in learning involves forming new circuits in motor systemmotor system
Relational Relational learning involves identifying learning involves identifying connections between stimuliconnections between stimuli
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Overview of LearningOverview of Learning
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Relational LearningRelational Learning Relational learningRelational learning involves connections between involves connections between
individual stimuliindividual stimuli Examples of relational learning includeExamples of relational learning include
– Forming an association between the image of an Forming an association between the image of an object and the sounds of that objectobject and the sounds of that object
– Knowing the content of a space and the relationship Knowing the content of a space and the relationship between the objects in that space (between the objects in that space (spatial learningspatial learning))
– Remembering sequences of events (Remembering sequences of events (episodic learningepisodic learning))– Viewing and recalling the actions of another person Viewing and recalling the actions of another person
((observational learningobservational learning))
14.6
The Hebb RuleThe Hebb Rule Donald Hebb argued that synapses that are Donald Hebb argued that synapses that are
active at the same time that the postsynaptic active at the same time that the postsynaptic neuron fires, are strengthened over timeneuron fires, are strengthened over time– Implies that repeated neural activity will produce Implies that repeated neural activity will produce
physical changes in the nervous systemphysical changes in the nervous system Rats exposed to enriched environments Rats exposed to enriched environments
exhibit neural changes:exhibit neural changes:– Thicker cortexThicker cortex– More glial cellsMore glial cells– More Acetylcholine(Long term Memory)More Acetylcholine(Long term Memory)
14.7
Neurobiological Foundations Neurobiological Foundations of Mental Health and Illnessof Mental Health and Illness
(Modified from Andreasen and Black, 2001)(Modified from Andreasen and Black, 2001)
Thoughts, Feelings, and BehaviorThoughts, Feelings, and Behavior
MindMind//BrainBrain SystemsSystems (mental/cognitive systems such as emotion or (mental/cognitive systems such as emotion or
language, chemical systems such as dopamine or serotonin).language, chemical systems such as dopamine or serotonin).
CircuitsCircuits
CellsCells
MembranesMembranes
MoleculesMolecules
GenesGenes
Limbic Cortex and Limbic Cortex and HypothalamusHypothalamus
Basal Ganglia- “The Basal Ganglia- “The Secretary”Secretary”
Limbic System- “The Driver”Limbic System- “The Driver”
Brain Development/AgingBrain Development/Aging
Recent research(imaging studies) have Recent research(imaging studies) have given scientists an estimate of brain given scientists an estimate of brain chemistry development:chemistry development:
Age 11 - 50% complete (pre-puberty)Age 11 - 50% complete (pre-puberty) Age 18 - 75% complete(post puberty)Age 18 - 75% complete(post puberty) Age 24-34 - 100% completeAge 24-34 - 100% complete Age 44 - 75% Age 44 - 75% Age 60 - 50%Age 60 - 50%
Addiction Risk FactorsAddiction Risk Factors
GeneticsGenetics Young Age of OnsetYoung Age of Onset Childhood Trauma (violent, sexual)Childhood Trauma (violent, sexual) Learning Disorders (ADD/ADHD)Learning Disorders (ADD/ADHD) Mental IllnessMental Illness
Short term memory processed into long term memoryShort term memory processed into long term memory
– AmygdalaAmygdala Controls rage, lust, fear and other strong emotionsControls rage, lust, fear and other strong emotions
– CerebellumCerebellum Balance and planning of movementBalance and planning of movement
AnandamideAnandamide
Sanskrit ananda means “bliss”Sanskrit ananda means “bliss” Chemical messenger involved in mood, Chemical messenger involved in mood,
memory, pain perception and appetitememory, pain perception and appetite Natural molecular keyNatural molecular key THC fits same receptorTHC fits same receptor Anandamide is fragile and breaks down Anandamide is fragile and breaks down
quicklyquickly– No intense high like THCNo intense high like THC
ChocolateChocolate
MJ use Lowers Glucose MJ use Lowers Glucose Metabolism in Frontal and Metabolism in Frontal and
Temporal LobesTemporal Lobes
P. hipp.
Medial OFC
Superior
Middle
Inferior
Temporal Gyri
Marijuana Makes People Stupid…
and they stay stupid..
Multiple Neurotransmitter Receptor Sites For Marijuana
Anandamide
GABADopamine
Glutamate
The Blood-Brain Barrier
THC Binds To Glial Cells of BBB
The learned helplessness that results from exposure to the absence of control generalizes to other situations. Marijuana creates the state of learned helplessness.
PSYCHOACTIVE CHEMICAL DEPENDENCE IS A PSYCHOACTIVE CHEMICAL DEPENDENCE IS A COMPLEX ILLNESSCOMPLEX ILLNESS
