8

to understand the working of the CNS , early in life

3/10 months until 1.5 years ( increase in brain weight 30%)

2 4 / 6 8 / 10 12 / 14 16 years of age ( increase in brain weight 5% 10% each 2 years )

brain growth takes pale without conccurrent increase in neuron nr

growth due to fglia cells and synapses

brain growth coincides with cognitive development

first 4 supurts coincide with the firt four stages of cognitive development

matures last ( compared to other brain regions)

another growt spurt at 8 years of age

growth spurt at 3 4 years of age

maturation continue up until 25 30

last in first out

(executive funtions → ageing)

continues trough life

birth of glia cells begins after most neurons are formed

axons are functional before myelination

regular adult functioning is attained only after myelination

starts after birth until 18 years of age

some region are myelinated after 3/4 years while others no myelination

used in dimple movements and sensory analyses

not myelinated : highest mental functions

*pruning* :synaptic pruning is a natural process that occurs in the brain between early childhood and adulthood. During synaptic pruning, the brain eliminates extra synapses

decline in gray matter at 6 to 7 years of age trough adolescence

white matter increases in the same time

gray matter loss due to neuron and synaptic pruning

tarts in dorsal parietal and sensorimotor regions

spreads laterally, caudally and rostrally

1. first region to mature are primary cortical regions ( basic motor functioning )
2. parietal regions controlling spatial language and skills mature at puberty ( 11/13 years)
3. tertiary regions like prefrontal cortex mature last in late adolsecene trough adutlthood

enviornmental deprivation longer than 6 months → serious consequnces for brain development

occipital cortex very sensitve for complex environemnt

density of synapses

length of synapses

adverse chilhood expirinces (ACEs) include

verbal or physical abuse

addiction of a family member

loss of parent

ACEs predict mental and physical health distruption at middle age

individuals with 2+ ACEs were 50 mire likely to have an addiction or attept suicide

ACEs compromise frontal lobe development

prenatal expirinces can also impact dentric organization and behaviours

ventromedial prefrontal cortex (VMPC):

empathy

impulse control

language

if developmnet not complete may result in anxiety and depresion

later to other problems

= location of excitatory synapses in particular

exposure to complex environment increases brain size

most noticebly in neocortex , gratest increase in occipital cortex

related to increase also increase in

1.density of glia cells

2.lenght of denditres

3.density of spines ( the location of most exitatory synapses)

young brain needs length

density will decrease for more length if needed

housing animals

changing objects to play with

showed increase in length of pysrlmidal cell dendrites in cortices (both young and older animals )

spine density decreases in young animals

spine dendity increases in older animals

similar functional benefits

performing better than impoverished counterparts

practicing a behivour ( palying a musical insturment)

expansion of reprentation of that behaviour in the brain

= plasticity

sensorymotor mapping of the fingers enlarges

while representation of the fingers not used remain unchanged

sparing of function follows infant leasions

earlier did not mean better, it meant worst

very poor outcomes in infants with early injuries

speech survives early brain damage

some elements of syntax and non language mat not

intlectual ability may decline as well

function that is affected

extent and location of the lesion

age at which the brain damage occurs (growth spurt )

1. before 1 year : disproportonetly grater impairments that later ones
2. between 1 and 5 years : followed by reorganization of brain function (rescue of speech functions)
3. older than 5 : permit little improvment of function

earlier leasion lower IQ more than later lesions

injuries before 1 year old produce overall more damage

1. language survives early left hemisphere injury
2. much of this survival seems attributed to appropriation of a potential language zone in the right hemisphere
3. this shift has a price → visuospatial orietation is impaired (crowding effect)
4. early lesions of right hemisphere produce deficits similar to those produced by such leasions in adulthood

a condition, caused by a brain injury, that results in a varying degree of weakness, stiffness (spasticity) and lack of control in one side of the body

left leasion depress only performance scores

right leasion depress both verbal and performance scores

complete shifts of language are also possible