Brain Development

Chapter 4

neurons (aka nerve cells)

neurogenesis - the birth of new neurons - pieces: cell body, dendrites, axon and myelin sheaths.

environment - glial cells and synapses

modes of communication - electrical which is action potential and chemical which are neurotransmitters

structure of brain

cortex - outermost layer: gray matter and white matter

two hemispheres: corpus callosum and lateralization

four lobes: frontal, temporal, parietal, and occipital

subcortical: forebrain (limbic, pituitary, hypothalamus, and thalamus), midbrain, and hindbrain

nature and nurture

plastic in response to experience

experience-expectant - brain “expects”/requires stimulation to develop normally: suggests a sensitive or crucial period, example severe child neglect

experience-dependent - brain will develop depending on individual experience: the case for stimulation and activity, no age restrictions but most plastic in first 3 yrs. of life.

brain development in infancy and childhood

many cells, few connections

synpatogensis - new connections, no age restrictions, but most plastic in first 3 yrs. of life

first area - sensorimotor and subcortical

last area - pre-frontal lobe

transient exuberance

efficiency as a result of synaptic pruning and myelination

synaptic pruning - trim away unused connections

myelination - faster and more coordinated thought

specialization of lateralization

begins prior to birth and strengths with experience - hemispheric dominance

increasing complex tasks require coordination of effort across the corpus callosum

resilient once developed, but if damage occurs- plastic!

brain development in adolescence

renaissance period of brain development - triggered by puberty and decreased gray matter (synaptic pruning) and more white matter (myelination)

mismatched timing of brain development - limbic system: early adolescence

prefrontal cortex - early adulthood

brain development on adulthood and late life

peak maturity - mid 20s

characteristic patterns of slowing and loss

gray matter - fewer dendrites, synapses, glial cells: on decline, plateaus, and drops of 80

myelin - continues increasing, shorter plateau, and depletes

adulthood and late life continued..

plasticity remains - requires greater effort and neurogenesis still possible, but less sustainable

compensation - increased activation and cognitive reserve

pathological brain aging

neurocognitive disorders - dementia as the cognitive symptom, Alzheimer's disease, vascular dementia, Parkinson’s disease, and Lewy body dementia

affects black and Latino populations more than white - health disparities and social and contextual differences