lecture 14

Question 1

motor development

Answer 1

between 1-3 months babies display hand movements similar to adults
develop pincer grasp at 10 mo
- emerging behaviors can predict neural maturation

Question 2

language development

Answer 2

language onset is between 1-2 years
around 5-10 words by 1 year
around 200-300 words by 2 year
around 25000 words by age 6 
largely complete by age 12

Question 3

language and motor development

Answer 3

language and motor skills develop in parallel to some degree but precise movements of muscles controlling speech sounds develop before children can speak
- even when motor skills developed to articulate most words vocabulary still progresses

Question 4

what are the major changes in language development

Answer 4

neural connectivity and myelination of speech zones

- happens at around 2-12

Question 5

development of problem solving ability

Answer 5

piaget: sensorimotor (0-2yr), preoperational (2-6), concrete operational (7-11), formal operational (12+)

Question 6

what are the neural underpinnings of piagets stages

Answer 6

grwoth spurts- sporadic period of sudden growth that lasts for ifnite time
epstein identified 5 spurts, first 4 coincide with piaget
due to growth of gial cells, blood vessels, myelin and synapses

Question 7

what does development of problem solving abilities tell us about brain development

Answer 7

if children perform a particular task poorly, can infer that brain regions governing task are not fully developed

Question 8

overman and colleagues

Answer 8

tested children on:
concurrent discrimination task (temporal lobe)
- around 12 m to learn all correct objects
nonmatching to sample (basal ganglia)
around 18 m to learn the pair

Question 9

experience on brain development

Answer 9

Hebb- how does experience impact brain development
found that rats raised in enriching kitchen performed much better than rats raised in barren environment- more and larger synapses and astocytes

Question 10

how does experience influence neural connectivity (pre and post natal)

Answer 10

chemoaffinity hypothesis- neurons or axons/dendrites are drawn towards signalling chemical that indicates correct pathway
postnatal- fine tuning of connections proceeds in an activity dependant manner

Question 11

abnormal expereince on brain development

Answer 11

absence of the right sensory experience at the right time can result in abnormal development
critical period: developmental window when some specific sensory experience has a long lasting influence on the brain

Question 12

imprinting

Answer 12

process that predisposes an animal to form an attachment to objects or animals at a critical period in development
- enlargement of synapses in chick forebrain

Question 13

3 experiments on abnormal experience

Answer 13

hebb- raised dogs in dark enclosures –> behaviorally muted and performed poorly on intelligence tests
harlow- seperated monkeys from their mothers –> incapable of forming normal social relationships in adulthood
riesen- showed absence of visual stimulation leads to atrophy of dendrites on cortical neurons

Question 14

stress in early life

Answer 14

associated with increased amygdala, decreased hippocampus and later development of depression and anxiety

Question 15

testosterone (androgen)

Answer 15

released during brief period during prenatal development: alters brain as much as alters sex organs
- sexual dimorphism at around 60 days
sex hormone for male

Question 16

estrogen

Answer 16

sex hormone responsible for distinguishing characteristics of female

Question 17

what parts of brain development are affected by hormones

Answer 17

number of neurons formed, number of neurons that die, cell growth, dendritic branching, synaptic growth, activity of synapses
- difference in receptors correspond to differences in volume

Question 18

rats reaered in complex environments- hormones

Answer 18

males showed more dendritic growth in visual cortex, females showed more dendritic growth in hippocampus, - same experience affects male and female brain differently

Question 19

gut bacteria and brain development

Answer 19

some neurodevelopmental disorders may be related to atypical microbiome

• mouse model of autism returned to normal from manipulation of gut bacteria
• proved gut bacteria can alter behavior

Question 20

injury and brain development

Answer 20

worst time for brain injury: last half of intrauterine period and first few months after birth
better time: first few years after birth (2) more resilient to deficits than damage in adults

Question 21

drugs on brain development

Answer 21

ongoing research

- low dosages can have potentially damaging impact on developing brain

Question 22

genetic abnormalities of brain developmeent

Answer 22

spina bifida- spinal cord abnormality due to the failure of the neural tube to close completely, motor problems
anecephaly- front end of neural tube doesnt close and forebrain fails to develop

Question 23

abnormal cell migration

Answer 23

schizophrenia- faulty connections produce a range of

- disorganized pyramidal neurons in hippocampus

Question 24

developmental disability

Answer 24

impaired cognitive functioning due to abnormal brain development
- many causes, genetic abnormalities, prenatal exposure to infections or toxins, birth trauma, malnutrition

Question 25

mechanism of developmental disabilities

Answer 25

examined brains of children with developemental disabilities and found dendritic growth was reduced
- suggests fewer connections in brain