Brain Development Flashcards
what is neurulation
formation of the hollow tube that eventually fold and become the spinal cord and brain
what is the biggest amount of change that happens from birth to one year
the amount of synapses (connections ) increase by 10X
called synaptogenesis
what is the process of pruning?
elimination of unused synapses after synpatogenesis
allows for brain to fine tune for specialized environment
in what developmetnal order are synapses grown and prune
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 )
which region experiences the most myelination after birth
prefrontal cortex
why does development happen in a layer /overlapping way
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)
what is the downfall of extended development
greater opportunity for maladaptive change
in what order (age) do which regions get myelinated
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
what is the pattern of growth / decay for grey matter
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)
which regions experiences one of the most white matter changes from age 5 to age 8
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
what combination of brain region fucntion leads to risky adolescent behaviour (dual-systems model)
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
describe the study of emotional evaluation and aging
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
what is the experience expectant system
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
give an example of the experience expectant system
binocular vision –> if newborn not exposed to normal exposure of light during development binocular depth perception will not develop
what is the experience dependent system
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
describe what happens to rats that are raised in enriched environments
develop better skills (perceptual, motor and maze solving)
abilities can be transferred to their pups
cortical and cerebellar changes also seen in enriched development
what is the sensitive period of development
developmental window where specific experience has long-term effects on behaviour and the brain
extra sensitive to certain stimuli
experience dependent
what is the critical period of development
narrow window of development where specific experience is required for normal development
rats and white noise study
evidence for sensitive period of development
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
describe study testing earlier and later trained musicians (sensitive period)
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
what are developmental disorders which arise from genetic causes
down syndorome
fragile x syndrome
what are the characteristics of Down syndrome
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
what are the characteristic of fragile X syndrome
more common in boys
intellectual disability more pronounced in non-verbal domains (forming letters and simple math)
developmental disorders cause by infections of toxins
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)
what is the primary deficit experience in Dyslexia
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 )
describe the phoneme discrimination reaction time study
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)
describe cell migration patterns in the brain tissue of someone with dyslexia
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
what are the main characteristics of autism
impairment in social interaction
restrictive or repetitive actives and interests, including repetitive motor actions (hand flapping)
describe brain development of someone with autism
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
