CHAPTER 5Infants and Toddlers

Physical Development

Half of all human genes are

involved in building the brain by

providing the codes for its basic

structures and functions.

Brain Development

Early Brain DevelopmentFormation and Migration of Neurons

• The brain is built of cells called neurons

• Neurons are the communication system of the brain

• A neuron’s job is to make connections with other neurons, constantly exchanging information

• A baby is born with 100 billion neurons

Early Brain DevelopmentFormation and Migration of Neurons

• Each neuron has an axon – a transmitter

• The axon is the long part of the neuron

• Axons send messages to other neurons

Early Brain DevelopmentFormation and Migration of Neurons

• Each neuron also has dendrites

• Dendrites are extensions that branch out

• Dendrites receive messages

Early Brain DevelopmentFormation and Migration of Neurons

• Information is transmitted through electrical impulses

• These impulses travel down the length of a neuron

• The impulse causes the neuron to produce a chemical response

Early Brain DevelopmentFormation and Migration of Neurons

• The chemical messenger then transmits the info from one neuron to the next through small gaps between the cells, called synapses

• Synaptogenesis is the creation of new neural connections or synapses

The Importance of Myelination

• Myelination consists of smooth layers of fatty proteins that sheath the neuron

• Electrical impulses travel 3x faster

• During prenatal development myelination occurs along the spinal cord

The most dramatic

myelination occurs before 2

years of age

Early Brain Development

• During early development, the brain generates about 2 to 3 times more neurons and connection than are needed to survive and function

Early Brain Development Pruning• Little used neural connections are eliminated

• These connections are ones that are not reinforced by the child’s environment

• Early experiences play a crucial role

• Pruning occurs throughout early childhood and into adolescence

Due to genetics or lack of reinforcement

(use it or lose it)

Keep

Toss

Reinforcement

Brain Development – Cerebral Cortex

• Left Hemisphere• Language processing• Develops rapidly around the

age of 2

• Right Hemisphere• Spatial relationship• Rapid development around the

age of 4 or 5

• This is the largest part of the brain• Controls higher thought process• Last part of the brain to finish growing• Easily influenced by the environment

Hi! Hey!

Brain Development – Cerebral Cortex

• Left Hemisphere• Logic• Reason (facts)• Objective• Verbal• Self-oriented• Categorical• Detail focused• Memory• Purposefulness• Words of Songs• Mathematics• Forms strategy• Order• Safe• Acknowledges

• Right Hemisphere• Intuition• Emotions• Subjective• Visual• Group-oriented• Relational• Whole picture focused• Creative• Playfulness• Tune of Songs• Arts (motor skill)• Forms possibilities• Imagination• Risk taking• Appreciates

Infant Brain Development

• By the time a baby is born, the brain controls important survival functions…• Breathing• Swallowing• Sucking• Heartbeat

• Sensory areas develop early • Smell• Taste• Touch• Sight• Hearing

Infant Brain DevelopmentBrain Plasticity

• Infant brains are more flexible than adults

• Allows the brain to be fine-tuned

• Helps the brain adjust to different situations

• Helps the brain recover from serious harm

Brain DevelopmentEnvironmental Effects• Environment shapes the way the brain forms

• Experiences are the chief architect of the brain

• Structure of the brain influences children’s interpretation of information

Brain DevelopmentEnvironmental EffectsEXPERIENCE - EXPECTANT

• Development will not happen unless a particular experience occurs during this critical period

EXPERIENCE - DEPENDENT

• Environmental inputs actively contribute to brain structure

• Experiences are not highly typical

• Can be positive or negative

Two types of environmental influences

Brain DevelopmentEnvironmental Effects

• Negative environmental effects increase risk for problems in brain development• especially during ‘experience – expectant’ processes

• Disruptions during the brain’s growth spurt can cause• Permanent reduction in brain size• Reduction in the number of neurons• Reduced myelination of cells• Decreased numbers of synaptic connections

NEONATAL DEVELOPMENT

Neonatal and Infant DevelopmentSight

• Poor vision• Looks for edges/contrasts• Not fully developed at birth• Blurry• Can track slow moving objects

Contrast ColorfulRed, blue, green

Patterns

Neonatal and Infant DevelopmentPerception

• Infants prefer to watch moving objects

• Infants are good at coordinating their movements with the movements of objects

• Infants also recognize and prefer complex patterns of motion made by people

• Infants detect depth and distance before they can crawl

The Visual Cliff

Click here to view the Visual Cliff video

Neonatal and Infant DevelopmentSound

• Can hear sounds that are whispered but not softer than that

• Cannot hear sounds of short duration as well as adults

• Prefer relatively high-pitched sounds

• Seem to be particularly attuned to human voices, especially own mothers’

• Prenatal exposure to sounds appears to “set” infants’ preferences for sounds after they are born

Neonatal and Infant DevelopmentTaste

• Newborns can distinguish among tastes that are sweet, salty, bitter, and sour – prefer sweet

Smell

• Newborns turn away and make faces when presented with strong or unpleasant smells

• Smells may be one of the first and most basic connections between neonates and their caregivers

Neonatal and Infant DevelopmentTouch

• The parts of the nervous system that process information about touch develop very early

• At birth, the presence of reflex responses to touch suggest the newborn is particularly sensitive on the face, hands, soles of the feet, and abdomen

• Temperature cues are used by infants to locate nourishment

Stages of Motor Development• Infants’ movements become more localized and

specialized during the first few years of life

• During the first year, infants’ reflexes become inhibited as the brain develops and they gain voluntary control over many of their movements

• After the first year, motor development mainly involves practicing and mastering previously learned skills

Neonatal Reflexes

Sucking Blinking Stepping

Rooting Tonic Neck Babkin

Palmar grasp

Moro Swimming

Babinski

Click here to watch a short video on neonatal reflexes

Stages of Large Motor Development

Involves movements of large muscles in the body

• Motor control precedes in a cephalocaudal direction, which means from the head to the feet.

• Head, trunk, and arm control appears before children are able to coordinate their hands and fingers – this is called proximodistal development

Stages of Large Motor Development• Lift head

• Sitting

• Crawling, Creeping

• Standing

• Walking

• The first year is achieving the above while the second year is when children try many variations in their movements

Stages of Fine Motor DevelopmentInvolves movement of the small muscles in the body

• Reaching

• Grasping

• Fingers in mouth

• Hands / feet

• Potty Control

Healthy Development• Safety

• Baby proof• Avoid Accidents• Car Seat

• Nutrition• Breast-feeding• Bottle

• Failure-to-Thrive (FTT)• Undernutrition

• Lack of food

• Malnutrition• Lack of proper calories

• Problems• Passive• Inactivity• Withdrawn• Avoid physical contact• Lag behind

• Language• Verbal• Reading• social

After children learn to walk, the leading cause of death is physical injuries 1/3 of all deaths for children 1 to 4 years of age

Benefits of Breast-Feeding for Infants and Mothers, page 160 Table 5.4

For Infants• Protein / Iron• Cholesterol / lactose (brain development)• Resistance to infections• Protection against diseases • Minimized risk of obesity• Slightly higher IQ & reading comprehension

For Mothers• Contact / intimacy• Weight loss• Faster recovery from childbirth• Delayed ovulation• Convenience• Less expense