Behavioral Neuroscience Exam 2

Heritability of Psychological Disorders

Heritability: genetic influence, what genes are “turned on”

• Influenced by environment and experiences

Anxiety disorders, OCD, PTSD, major depressive disorder

• 20-45%

Alcoholism, anorexia

• 50-60%

ASD, ADHD, schizophrenia, bipolar disorder

• 75%+

General psych traits

• 50%

Gene

A sequence of nucleotides in DNA that create a specific protein

How genes work

Creat proteins which are molecules that have specific jobs in your body

Rosalind Franklin

Took first picture of double helix while working with Watson and Crick, but they got credit for it

DNA

Double helix structure, inactive unreadable form of your genes

“Closed recipe book”

RNA

Unzipped double helix, active readable form of your genes

“Open recipe book”

• Ingredients = amino acids

Transcription

Opening of DNA to RNA

Translation

“Read recipe”

Gather ingredients: creating amino acids

Put ingredients together: creates proteins

Genes create proteins and proteins do jobs

• Create neurotransmitters

• Create receptors for neurotransmitters

• Cause the reuptake of neurotransmitters

• Create new connections between neurons

• Trigger the growth of new neurons

• Trigger the death of existing neurons

All these biological mechanisms working together produce behavior

Epigenetics

There are molecules in your cells that can either increase or decrease the gene transcription process

• Turning your genes on or off

These molecules are influenced by your diet, exposure to toxins, medications, and experiences

Exposure to prenatal stress can result in

higher stress responses, anxiety, impaired memory, hyperactivity, increased risk of schizophrenia

Exposure to prenatal malnutrition can result in

Increased risk of depression and impaired cognitive function

Exposure to prenatal environmental toxins can result in

Cigarettes = difficulty in regulating emotions, attentional issues, excitability, and irritability

Air pollution = difficulty in inhibitory control and poorer academic acheivment

Great chance of epigenetic changes

Birth → 2 years old

Postnatal Experiences

Newborn rats that had mothers that gave them low rates of licking had changes in gene expression that resulted in higher stress responses later in life

• changes could be reversed if they were then fostered by mothers with high rates of licking and grooming

Cannabis exposure during adolescence changes gene expression resulted in altered dopamine levels

• reduced reward, motivation, and cognition

Gestation in First Trimester (0-12 weeks)

Neural plate forms (foundation of central nervous system)

Forms at 16 days after conception

Neural plate folds into neural tube and neural tube closes 6-7 weeks after conception

• Neural tube becomes brain and spinal cord

• Closing of neural tube required folic acid

  • Deficit leads to Spina Bifida

Movement and sense of touch start to develop

Gestation in Second Trimester (13-26 weeks)

Myelination of peripheral nerves begin

Brainstem matures (controls heart rate, breathing, blood pressure)

Sense of taste and hearing start to develop

• Fetus will be able to taste things you eat; wider variety consumed → less picky kid

• Start talking to the fetus

Gestation in Third Trimester (27-40 weeks)

Brain triples in weight due to rapid development of neurons

Cerebellum develops

Sleep cycles develop

Cerebral cortex begins to function at birth

Neural Connections in First Few Years of Life

1000 neural connections formed every second (proliferation)

Proliferation period is followed by a period of synaptic pruning

• Occurs in sensory pathways, then language areas, then higher cognitive function areas

Early childhood Myelination

Increases sharply from birth-2 years of age before leveling off for the rest of childhood with no sex differences present

• Increases sharply again during adolescence