l04 slides
TRANSCRIPT
-
8/14/2019 L04 Slides
1/13
1
Repeated Administration
Addiction Physical and psychological dependence
Tolerance More drug is needed for same effect
Sensitization Same amount of drug induces larger effect
How Does a Drug Work?
Drug Mechanisms
Agonist- Facilitates or
mimics NT
Antagonist- Prevents NT
action
For example:
Drug Effects
Block Action
Potential
-
8/14/2019 L04 Slides
2/13
2
Sites of Drug Action Acetylcholine
Drug Effects Serotonin
-
8/14/2019 L04 Slides
3/13
3
Drug Effects Dopamine
The Reward Pathway
Reward
nucleus
accumbens
Planning
Inhibition
Self-control
Emotional memory
Prefrontal
cortex
amygdala
Ventraltegmental
area
DA
Video-Major Points
All drugs self-
administered
by animals are
also self-administered
by people
-
8/14/2019 L04 Slides
4/13
4
Drug Effects
http://learn.genetics.utah.edu/content/addiction/drugs/mouse.html
Cocaine & Amphetamine
Routes of Administration Behavioral Effects
Autonomic functions
Increase blood pressure
Increase body temperature
Psychomotor stimulant effects Decreased fatigue, Increased arousal
Reduced appetite
Elevated mood (euphoria)
-
8/14/2019 L04 Slides
5/13
5
Changes in Brain Function Drug Effects
Addiction & Release of DA
Time (hours)
Cocaine Self-injectionsTime (hours)
Amphetamine Self-injections
Marijuana
60 Cannabinoids
THC psychoactive agent
-
8/14/2019 L04 Slides
6/13
6
Behavioral EffectsLow to Moderate Doses
Disinhibition, relaxation, drowsiness Exhilaration, euphoria
Sensory - perceptual changes
STM impairment
Balance impaired
Decreased muscle strength
Small tremor
Poor on complex tasks (e.g., driving)
Large Doses
Pseudo hallucinations
Synesthesias
Impaired judgment, slower RT
Pronounced motor deficits
Disorganized thoughts
Confusion
Paranoia
Agitation
Receptor Location
CB1 receptor
Effect on the Brain Drug Effects
-
8/14/2019 L04 Slides
7/13
7
%c
hangeinaccumbensDA
Increase In Dopamine Inhibition and Excitation
Embryonic Development Early Neural Development
-
8/14/2019 L04 Slides
8/13
8
Early Neural Development Early Brain Development
Early Brain Development Rapid Growth
Postnatal
Prenatal
-
8/14/2019 L04 Slides
9/13
9
Steps in Brain Development
1. Neurogenesis
2. Migration
3. Differentiation
4. Synaptogenesis
5. Apoptosis
6. Remodeling
1. Neurogenesis
Starts with Closure of Neural Tube
1. Neurogenesis
Birth-Dating Neurons
BrdU -synthetic
nucleoside-
inserted into DNA
1. Neurogenesis
Ventricular Mitosis
Stem Cell: Genetic Memory For Division
-
8/14/2019 L04 Slides
10/13
10
Adult Neurogenesis
The Olfactory BulbHippocampus
2: Migration
Importance of Radial GliaCell Adhesion Molecules
Radial Migration
Inside-Out Cortical Pattern
Tangential Migration
Interneurons
Aberrant Migration
Dyslexia: A region of the left hemisphere important
for language comprehension
3. Differentiation
Migrating cells immature
Structurally
Functionally
At destination, determined by:
Genetic Blueprint
Proteins
Environmental Signals
From Surrounding Cells
-
8/14/2019 L04 Slides
11/13
11
Induction Experiment 4. Synaptogenesis
Axons
Chemotropic Guidance 4. Synaptogenesis:Myelin
Begins before birth in M1 and S1
Continues into adolescence (frontal lobes)
-
8/14/2019 L04 Slides
12/13
12
4. Synaptogenesis: Dendrites
Usually begins after migrationBegins prenatally, but continues postnatally
5: Apoptosis
Up to 50% neurons born in
1st 7 months die
Neurotrophic Growth Factors
Required for Survival
Brain structure as much
about sculpting as growth
6. Synaptic Remodeling
Max # of Synapses at between 1 and 5 yrs of age
Development Done?
By 5-6 years of
age, 95% of
structural
developmentcomplete
-
8/14/2019 L04 Slides
13/13
13
Nature? Intrinsic factors (genes)
Mutations
Nurture? Extrinsic factors (environment)
Twin studies
What determines development?
Phenylketonuria (PKU)
Enzymatic Disorder
Phenylalanine
IQ < 30
Episodic Seizures
What determines development?
The Teenage Brain The Aged Brain
Normal Aging: Cortical Thinning