Chapter 4

The First Two Years

  • Infancy (first year) through toddlerhood (2-3ish years)

Changes in Body Proportions

  • Children grow in a Cephalocaudal trend:

    • Head to Tail

    • Head develops more rapidly than lower part of body

  • Proximodistal trend:

    • Near to far

    • Growth proceeds from center of body outward

    • In puberty, the Proximodistal trend reverses

Body Growth

Faster growth than at any other time (occurs in spurts)

Neurons and Their Connective Fibers

Vocabulary

  • Neurogenesis: The creation of new neurons

  • Synaptic connection: the specialized junctions where neurons (nerve cells) communicate with each other or other cells by transmitting electrical or chemical signals

    • Growing Synaptic connections = growing/creating new neurons and dendrites within the connectome

  • Synaptogenesis:

  • We LOVE dendrites because they accept info/signals from other neurons and pass the info into the cell body

    • the more we have the most efficient we think

      • Every time you learning something new, you are growing dendrites

  • 9, 32, 66, and 83 are the ages correlated with the connectome (a comprehensive, structural map of the neural connections within a brain)

    • 9: A change in how we use the brain

    • 32: When the brain has “matured”

Development of Neurons

  • Establish unique functions by forming synaptic connections with neighboring cells

    • Stimulation vital for survival of neurons; formation of new synapses

  • Synaptic Pruning: the brain’s natural process of eliminating unused or weaker synapses between neurons to make neural networks more efficient; removing unnecessary synapses, strengthens remaining ones

    • Age 2ish: massive synaptogenesis followed by pruning

Myelination

  • Insulating fatty sheath covering nerve fibers

  • Improves efficiency of message transfer

  • Glial cells: responsible for myelination

    • Account for half the brain’s volume

    • Multiply rapidly in first two years

Regions of Brain Development

  • Basic functions

  • Motor & sensory processing

  • Emotional & memory center

  • High cognitive functions

Cerebral Cortex and Cortical Regions

  • Cerebral cortex: 85% of brain's wt, surrounds rest of brain

  • Cortical regions develop as capacities emerge

  • 1st yr: auditory and visual; body movement areas

  • Occipital, parietal, cerebellum (sco nak uds)

  • Infancy - preschool: language areas

  • PFC, temporal lobe (400 next sido)

  • Prefrontal cortex:

  • Responsible for complex thought

  • Functions more effectively from age 2 most

  • The main part of the prefrontal cortex is executive function (a group of neurons that direct everything)

The brain

  • frontal lobe: movement, thinking, personality, and purpose

  • Occipital lobe: vision

  • Temporal lobe: hearing, memory, and language processing

  • Parietal lobe: sensory, touch

Lateralization of the cerebral cortex

Left hemisphere

  • Sequential, analytic processing

  • Verbal communication

  • Positive emotion

Right hemisphere

  • holistic, integrative processing

  • Making sense of spatial information

  • Regulating negative emotion

Brain plasticity

  • highly plastic cortex during first few years:

  • Many areas not yet confirmed to specific functions

  • High capacity for learning

  • Early experiences influence its organization

  • If injury occurs and loss of function happens in the brain, the brain will work to improve, learn and reorganize the functions again

  • If part of cortex is damaged, other areas can take over

  • If you want a child to know/learn a skill, teach it to them before the age of 11

Sensitive periods in brain development

  • appropriate stimulation vital for brain growth

  • Early, extreme sensory deprivation may result in permanent brain damage and loss of functions

  • Rushing early learning overwhelms neural circuits impedes brain’s potential

Experience-expectant brain growth

  • occurs early and naturally

  • Rapidly developing organization

  • Depends on ordinary experiences “expected” by brain for normal growth

Experience-dependent brain growth

  • occurs throughout our lives

  • Growth and refinement

  • Results from specific, individual learning experiences

Sensitive periods

  • Sensitive period: A specific window in time where the brain is primed and ready to learn a new skill in the environment

  • During a sensitive period, any stimuli is/can be learned

  • Learning languages: birth to age 7

  • Vision: first two years

  • Motor skills: first four years

  • Emotional attachment: first two years (particularly first 6 months)

Changing states of arousal

  • sleep-wake pattern gradually shifts to night-day schedule, and total sleep time declines

  • Lower quality of sleep linked with distractibility and behavioral problems

  • Circadian rhythm isn’t set until a minimum of 2 months of age

  • According to research, bedtime for toddlers need to be 7 pm is the best time for sleep training

Influences in early growth

  • heredity

  • Nutrition

    • breastfeeding vs bottle-feeding

  • Malnutrition

Nutrition and Breastfeeding

  • Crucial for development in first two years

  • Benefits of breastfeeding:

  • Nutritional completeness

  • Correct fat-protein balance

  • Helps ensure healthy physical growth

  • Protects against disease

  • Protects against faulty jaw and tooth development

  • Digestibility

  • Smooths transition to solid foods

  • Colostrum: pre-milk

Emotional Well-Being

  • affection as vital as food

  • Growth faltering: weight, height, and head circumference substantially below norm

    • infants are withdrawn and apathetic

    • Often result of disturbed parent-child relationship

    • May cause lasting cognitive and emotional difficulties

  • Non-organic failure to thrive is interchangeable with the term of an infant growth is faltering but there is no known cause

  • Psychosocial dwarfism

Reflexes: built-in reactions to stimuli

  • Rooting reflex: when infant’s cheek is stroked, or the side of the mouth is touched

  • Sucking reflex: newborns automatically suck an object placed in mouth

  • Moro reflex: a neonatal startle response that occurs in reaction to a sudden, intense noise or environment

  • Grasping reflex: occurs when something touches the infant’s palms

  • Swimming reflex: if you put a newborn in a body of water, they naturally start swimming

Motor development

  • Gross-motor development: crawling, standing, walking

  • Fine-motor development: reaching, grasping

  • Rate of motor progress varies

Vision

  • The least developed sense when born

  • by 3 months

  • Matches voice to face

  • Distinguish between male and female

  • Discriminate between faces of own ethic group and those of others

Developments in hearing

  • One of the most developed sense when born

Smell

  • one of the most activated senses when born

  • Smell is better as a newborn than as an adult

  • Newborns can sniff out their own parents