6/10- Neuroscience of Adolescence Flashcards
Common disorders seen to arise in adolescence? Estimated age ranges?
- Impulse control disorders (early; 5-15)
- Anxiety disorders (early; 5-20)
- Substance use disorders (12-25)
- Schizophrenia (12-23)
- Mood disorders (relatively long; 15-37)
IMPORTANT SLIDE!!!
Adolescent ___ is associated with adult ___? Examples?
Adolescent problem behavior is associated with adult psychopathology
Early problem behavior:
- Tobacco use
- Alcohol use
- Drug use
- Trouble with police
- Sexual intercourse
Externalizing disorders:
- Antisocial personality disorder
- Drug abuse/dependency
- Alcohol abuse/dependence
- Nicotine dependence
What are the primitive regions of the brain (divisions)?
- Rhomboencephalon
- Mesencephalon
- Diencephalon
- Telencephalon
What neuronal mechanisms influence formation and maintenance of connections?
- Migration (neural movement)
- Aborization (extension of dendritic arms of the cells)
- Pruning (neuronal loss)
- Myelination (“insulation” of the axons)
Timeline and result of disruption: migration?
- Occurs prenatally
- Disruptions during 2nd TM implicated in schizophrenia and other disorders
Timeline and result of disruption: pruning?
- Increases at ~ age 2
- Brian processing becomes faster as superfluous connections are trimmed
Timeline and result of disruption: myelination?
- Different areas of the brain complete myelination at different ages
- Cortical association areas finish myelinating later so complex reasoning less in childhood
- Frontal lobes finish myelinating later, influencing attention, decision making, impulse control
T/F: There are different patterns of white matter maturation during adolescence?
Measured by what?
True;
- Relative white matter volume
- Centered MT ratio
T/F: Grey matter consistently increases during neuronal maturity
False; there are increases and decreases
What disease specific patterns may be seen in brain development (by brain volume and grey matter volume)
- ADHD
- COS: childhood-onset schizophrenia (progressive and region-specific loss of cortical gray matter)
Common genetic variants influence what structures? How/what influences?
Common genetic variants influence human subcortical brain structures; this paper shows single genetic variant that can influence size and shape of putamen
- Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance, and vesicle transport
- Identification of these genetic variants provides insight into the causes of variability in human brain development, and may help to determine mechanisms of neuropsychiatric dysfunction
T/F: The propensity to use drugs is a uniquely human phenomenon?
False (also seen in bees, birds, cats…..)
- Best animal model = self-administration
What are most common drugs of initiation?
- Marijuana (70%)
- Pain relievers (13%)
- Inhalants (6%)
- Tranquilizers (5%)
- Stimulants (3%)
What population groups are using the most (percentage using during the past month)?
- Mostly 18-20 yo (23%)
- 21-25 yo (20%)
T/F: Past month tobacco use is decreasing
True
What percent of the population in the most likely age groups exhibit current, binge, and heavy alcohol use?
- Almost 70% of 21-30 yo
- Still in the 50’s% throughout 40s and 50s
- 42% in > 65 yo
No inverted view!
(as in illicit drug use)
T/F: Marijuana use is increasing
True
- 6% of the population uses > 300 days/yr
- 8% of the population uses 20+ days in past month
How does nicotine exposure in adolescence change the brain?
Changes dendritic arborization process
- Changes in patterns of synaptic activity
- Can sculpt late brain development
- Consequent effects on synaptic interconnection patterns and behavior regulation
How does marijuana exposure in adolescence change the brain?
- Heavy marijuana use during adolescence and into young adulthood may be associated with altered neural tissue development and interference with neuromaturation that may have neurobehavioral consequences
- See increased cortical thickness with increased lifetime marijuana use
- Actually see differences in baseline (for people using alcohol and marijuana versus control)
- Some marijuana use does not give rise to these changes, but high and sustained use does
T/F: addiction is a failure of resolve/a lack of willpower
False; addiction is a brain disease!
In what ways is addiction a brain disease?
- Different drugs of abuse target distinct brain networks and nuclei
- Drugs of abuse alter neuronal networks and brain nuclei
- Drugs of abuse alter 2nd messengers, transcriptional elements, and eventually DNA synthesis
- Brain changes caused by genetics (i.e. differential expression of proteins) and the environment (e.g. stress) alter an individual’s response to drugs of abuse
Levels of what (NT-related things) predict reinforcing properties?
Dopamine (D2) receptor levels predict reinforcing properties
- Participants who liked the effects of methylphenidate had significantly lower levels of D2R
Dopamine transporter genotype predicts reinforcing effects of amphetamine
- There is decreased dopamine transporter in meth abusers (in caudate and putamen)
- 9/9 genotype doesn’t feel amphetamine effect as much (9/10 intermediate and 10/10 experience great effect and are most susceptible to abuse)
How does the environment effect neuroscience/development: enriched environment?
More:
- Neurons and synaptic connections
- Blood capillaries
- Mitochondrial activation
(rats)
How does the environment effect neuroscience/development: sight of mother’s face?
Sight of mother’s face stimulates endogenous opiates and the production of CRF in infant’s hypothalamus
- Activating sympathetic nervous system
- CRF also stimulates production of dopamine
How does the environment effect neuroscience/development: prolonged stress?
Prolonged stress results in neuron loss, especially in hippocampus
How does the environment effect neuroscience/development: abuse, neglect, under-stimulation and prolonged shame?
- Decrease level of endorphins, CRF, and dopamine
- Increase stress hormones and noradrenaline
Adverse childhood experiences (ACE) increase risk of what?
- Depression (~4x)
- Alcoholism (~4x)
- Illicit drug use (~3x)
___ increases the likelihood of depression, but ___ plays an important role
Stress increases the likelihood of depression, but genetics plays an important role
- Function of genotype for serotonin transporter (ss are 2-4x more likely to develop major depression)
Leading causes of death (2010)
- Heart disease
- Cancer
- Respiratory diseases
- Stroke
- Accidents
- Alzheimer’s
- Diabetes
- Nephritis
- Influenza
- Suicide
Link between depression and suicide:
__% are depressed at time of suicide
__% lifetime risk of suicide with untreated major depressive disorder
__% lifetime risk of suicide with treated major depressive disorder
Link between depression and suicide:
67% are depressed at time of suicide (probably more that just didn’t see doctor)
20% lifetime risk of suicide with untreated major depressive disorder
0.14% lifetime risk of suicide with treated major depressive disorder!
What subcortical structures are responsible for processing social/affective information?
- Amygdala
- Hippocampus
Responsibilities of amygdala?
Can be the thing that triggers/sucks you back in; so powerful
- Key in sending and receiving mechanisms for facial expressions, hearing and touch
- Key component in neural networks associated with experiences of fear, attachment, early memory, emotion throughout life-span;
- Rapid appraisal of threat
- Initiates fight/flight response
- Retains early learning and unconsciously integrates it into present experience;
- Damage causes deficits in visual memory and auditory recognition of fear and anger
- Damage results in reduced social judgment
- Critical component of emotional memory
Responsibilities of hippocampus?
(Atrophy of hippocampus tied to depression)
- Vulnerable to sustained stress mediated via glucocorticoids with resultant dendritic degeneration and cell-death
- Hipppocampal volume decreases with chronic stress
- Critical for encoding and storage of explicit memory for spatial, semantic, and temporal information
- Necessary for new episodic and autobiographical learning
- Damage leads to anterograde amnesia;
- Biological effect of secure attachment protects hippocampus from stress mediated via glucocorticoids
- Especially vulnerable to insults of stress or anoxia;
- Adult women of childhood abuse have decreased left hippocampal volume and increased dissociative symptoms
What results from damage to anterior cingulate gyrus?
- Decreased empathy
- Emotional instability
- Disruption of HPA and ANS functioning
- Increased responsiveness to stress
- Decreased expressiveness
- Reduced motivation to communicate
- Mutism
- Inappropriate social behavior
- Impulsiveness
