Brain Development

Question 1

what is neurulation

Answer 1

formation of the hollow tube that eventually fold and become the spinal cord and brain

Question 2

what is the biggest amount of change that happens from birth to one year

Answer 2

the amount of synapses (connections ) increase by 10X

called synaptogenesis

Question 3

what is the process of pruning?

Answer 3

elimination of unused synapses after synpatogenesis

allows for brain to fine tune for specialized environment

Question 4

in what developmetnal order are synapses grown and prune

Answer 4

first region to grow and prune is sensorimotroe cortex

second in the parietal and temporal cortex

prefrontal is the last to experience growth and pruning

(don’t occur one after the other however, there are overlapping periods )

Question 5

which region experiences the most myelination after birth

Answer 5

prefrontal cortex

Question 6

why does development happen in a layer /overlapping way

Answer 6

the extended period allows for better adaptation to development

overlapping of regions allows for them to better interact with each other (specialization in one region can promote specialization in another)

Question 7

what is the downfall of extended development

Answer 7

greater opportunity for maladaptive change

Question 8

in what order (age) do which regions get myelinated

Answer 8

1 months - very little myelination mostly at cortico-spinal tract

3-6 moths orbital myelination

7-9 months corpus callosum development

all white matter pathways developed at 9 months

Question 9

what is the pattern of growth / decay for grey matter

Answer 9

increases until 8 or 9 then decreases

within grey matter there is white matter –> More myelination in white –> integrates into grey matter –> grey matter become more white –> looks like there is less grey but Is just a changed composition (mixed with glia and axon projections that aid in connection involved in brain and skill development)

Question 10

which regions experiences one of the most white matter changes from age 5 to age 8

Answer 10

big region of white matter change with arcuate fasciculus

increase in white matter here related to better reading skills

helps us learn about brain networks important for language

Question 11

what combination of brain region fucntion leads to risky adolescent behaviour (dual-systems model)

Answer 11

the inmatture still developing prefrontal cortex (cognitcve control system, top-down processing) mixed with the matured limbic system responsible for seeking out reward

lack of cognititve control of frontal cortex over emotions may be the reason why mental health disorder also emerge at this age

Question 12

describe the study of emotional evaluation and aging

Answer 12

methods –> shows people positive end negative pictures, had them rate how negative images made them feel

how negatively the negative pictures were related decreases with age

amygdala less prepared to find stimuli emotionally

Question 13

what is the experience expectant system

Answer 13

the idea that the nervous system has evolved to “expect” certain experiences during development that occur in almost all newborn

development very effected when these experiences the system expects are absent

basic function, less flexible, develops earlier

Question 14

give an example of the experience expectant system

Answer 14

binocular vision –> if newborn not exposed to normal exposure of light during development binocular depth perception will not develop

Question 15

what is the experience dependent system

Answer 15

system based on personal experiences –> not required for nervous system to develop normally

input at certain age of certain skills like music important for being able to develop that system

more complex, flexible, develops later

Question 16

describe what happens to rats that are raised in enriched environments

Answer 16

develop better skills (perceptual, motor and maze solving)
abilities can be transferred to their pups
cortical and cerebellar changes also seen in enriched development

Question 17

what is the sensitive period of development

Answer 17

developmental window where specific experience has long-term effects on behaviour and the brain

extra sensitive to certain stimuli

experience dependent

Question 18

what is the critical period of development

Answer 18

narrow window of development where specific experience is required for normal development

rats and white noise study

Question 19

evidence for sensitive period of development

Answer 19

deaf children that received cochlear implant before 24 months vs children that got them after development the same amount of language understand as compared to hearing children while ones that didn’t did not

second language learning –> simultaneous language learners had changes in brain structure of basal ganglia in relation to being able to produce the proper accent

absolute pitch

Question 20

describe study testing earlier and later trained musicians (sensitive period)

Answer 20

tested early (learning before 7) and later trained musicians with same total amount of trained

played rhythms and asked them to tap along

early trained musicians were more aligned with the rhythm

brain findings –> more white matter density in corpus callous in early trained musicians

why corpus callosum? influenced by environmental facts, experiences significant change between 6 and 8, important for bimanual skills

Question 21

what are developmental disorders which arise from genetic causes

Answer 21

down syndorome

fragile x syndrome

Question 22

what are the characteristics of Down syndrome

Answer 22

intellectual disabilities in both verbal and non verbal domains

may have special abilities / interest (ex. calendar memory)

sociable personalities

slowed condition development in childhood and accelerate cognitive aging in adulthood

Question 23

what are the characteristic of fragile X syndrome

Answer 23

more common in boys

intellectual disability more pronounced in non-verbal domains (forming letters and simple math)

Question 24

developmental disorders cause by infections of toxins

Answer 24

viral infections such as rubella or herpes

fetal alcohol syndrome (kids also at higher risk of ADHD, impulsivity, social and emotional difficulties and substance abuse)

Question 25

what is the primary deficit experience in Dyslexia

Answer 25

phonological processing (linking particular letter to particular sounds)

difficulty with consonants as they are rapidly changing in time\

dyslexia = less common in language with less complex phonological soundings (French and English are particularity bad for dyslexics )

Question 26

describe the phoneme discrimination reaction time study

Answer 26

Looked at functional connectivity between superior temporal gyrus left (auditory, Wernicke’s) and inferior frontal gyrus left (frontal, Broca’s)

Greater Functional connectivity related to being able to discriminate sounds

people with dyslexia takes longer to discriminate sounds (less white matter in the arcuate fasciculus)

Question 27

describe cell migration patterns in the brain tissue of someone with dyslexia

Answer 27

cell migrations irregularities in the Sylvia fissure (i.e Wernicke’s area and inferior parietal cortex),Disrupts connections between visual word-form area and inferior frontal lobe (Broca) that is important for decoding the sounds of words and translating sound to action.

the top layer of the cortex has less cell bodies –> one pocket in layer that is over populated –> suggest during cell migration the neurones ended up in the wrong place

Question 28

what are the main characteristics of autism

Answer 28

impairment in social interaction

restrictive or repetitive actives and interests, including repetitive motor actions (hand flapping)

Question 29

describe brain development of someone with autism

Answer 29

overall Brian volume is enlarged

children have increase cortical thickness and white matter in early development but is follows by a slower rate of myelination later leading them to fall behind in white matter development and cortical thickness