Lecture 4 - The amazing newborn and physical development in Infancy

Newborn Baby’s Appearance - Average Dimensions

20 inches, 7.5 pounds

7.5-9.5 normal, above is irregular

boys are typically longer than girls

Do baby’s come attractive out the womb?

skin looks very red and splotch

eyes are puffy

potbelly

pointy head

Babiness features

rounded face, chubby cheeks, large forehead, small mouth

The Apgar Scale - 5 Criteria

Rated out of 0-2 for each criterion

1. Heart Rate

2. Respiratory Effort

3. Muscle tone (limp or rigorous muscle tone)

4. Color (blue or normal color)

5. Reflex irritability (pulls on the arm and should automatically recoil)

How often is the Apgar scale measured

1 minute and 5 minutes after birth

What do the numbers in the Apgar scale mean?

7-10 indicates good physical condition

4-6 babies may need some assistance

3-below indicate emergency, baby needs help

Reflex

an inborn, automatic response to a particular form of stimulation. organized behavior patterns that govern the newborn’s movement

• involuntary

Purpose of Reflexes

to provide newborns with adaptive responses to their environment before they have the opportunity to learn about the world

Some reflexes baby’s have out of the womb

1. Sucking

2. Eye Blinking

3. Withdrawal

4. Babinski - toes fan out, then curl

5. Rooting- finding nipple

6. Moro - arches back and braces when dropped

7. Palmer - voluntary grasping

8. Tonic Neck - lies on back and turns to the side, one arm comes up

9. Crawling - voluntary control

10. Stepping - voluntary walking

11. Escape - keeps breathing channels clear and not suffocation

Characteristics/Nature of Relfexes

• Some have survival value (e.g., rooting- finding the nipple, sucking)

• Some are precursors for later motor skills (e.g., stepping reflex- stimulates muscles and NS)

• some are remains from earlier versions of homo sapiens- e.g., moro reflex (startle response)

• Duration- most disappear during the first 6 months

• Helpful for diagnosing early neurological problems

Touch for newborns

Sensitivity to touch and pain is well developed at birth

• helps stimulate physical and emotional development

Taste and Smell for newborns

• higher development sense of taste - can tell the difference between sour and sweet and bitter - babies tend to like sweet the most

• able to communicate taste and odor preferences. some odor preferences are likely innate

• attracted to the odor of mother’s lactating breast (helps them find food and mother)

Hearing for newborns

• newborns prefer complex sounds (like voices or music)

• They can distinguish almost all sounds in human languages (come prepared to listen basically)

• can lactate + orient to sound at 2 months. slow.

Vision for newborns

• least mature of newborn senses

  • visual sensors in the brain and eyes are still developing

• visual acuity is limited

  • fineness to discrimination

Newborn States - 5 different states of arousal

states of arousal = degree of sleep and wakefulness

Sleep and crying are the two main focus points

Sleep

babies spend most of their time sleeping

• time spent: 16/18 hours a day (hours are non-consecutive and unpredictable)

  • this leads to sleep deprivation for the parents because they keep having to wake up to care for their child

Babies alternate between REM and non-REM sleep

In REM sleep, babies’ brains and bodies are more active. Babies spend 50% of their sleep in REM; stimulation for brain (arms and legs move)

non-REM: brain is quieter (deep sleep)

Crying

Babies spend 2-3 hours crying or on the verge of crying

Function= babies communicate their needs through crying

There are different types of crying: mad, basic, pain

• hunger is the most common cause of crying

• crying is increased during early weeks, peaks at about 6 months, then declines

Impact = stimulate strong feelings of arousal and discomfort for caretakers or bystanders

Ways to soothe a crying infant

• rocking

• holding

• feeding

• swaddling in a blanket

What is the energy needs of a baby, how much time is breastmilk recommended for

2x more of those of adults

25% of the intake is devoted to growth in babies

breast feeding is recommended for around 6 months exclusively, 1 year with food

Which form of food is preferred: breastmilk or formula? What are its advantages

Breast Milk

Advantages:

• correct balance of fat + protein

• nutritional completeness

  • only need breastmilk, no other food

• Protection against disease

  • antibodies are transferred to a baby from mom (have fewer respiratory and intestinal illnesses, decreased infections

• Digestibility

• Smoother transition to smaller foods

• Cheaper, more immediate, safer

Breast Milk advantages for mother

Weight loss

Breast Cancer Protection

Three Reasons why formula is sometimes considered

1. Medical reasons (mom is taking antidepressants or medication and doesn’t want to transfer it to the baby)

2. Historical trends (around 1970-2010, formula had just come around, it was easier and more normalized)

3. Societal structures and barriers (not comfortable feeding baby in public)

In the first 2 years, how do infants grow?

• They grow in spurts

• Infants plump up an fill out- their “baby fat” (9 months)

• Infants grow unevenly

Cephalocaudal Trend

organized pattern of physical growth + motor control that proceeds from the head to the tail (top to bottom)

• growth of the head and chest grows first, then the limbs

Proximodistal trend

pattern of physical growth and motor control that proceeds from the center of the body outward

• arms and legs grow before hands and feet

• fine motor control takes time to develop

Neuron

nerve cells that store and transmit information, electrically excitable

• at birth you have nearly all existing neurons

Synapses

the gaps between neurons, across which chemical messages are sent

Neurotrasmitters

chemical messengers of the nervous system; chemicals released by neurons that cross the synapse to send messages to other neurons

What big development happens in the first two years?

connections between neurons occur

• happens at an amazing growth of neural fibers and synapses (very fast rate)

• experience and stimulation play a key role

• eventual synaptic pruning- unused and unnecessary synapses are eliminated

Synaptic pruning

unused and unnecessary synapses are eliminated

Myelination

process, which neural fibers are coated with an insulating fat sheath called myelin - this sheet speeds up the rate at which chemical messages are sent between neurons

Glial Cells

Cells that are responsible for the myelination of neural fibers, which improves the efficiency of message transfer

Brain Plasticity

brains willingess to change

P. 122 of textbook says:

The extent to which plasticity depends on is several factors, including age and time of injury, site and severity of damage, skill area, and environmental supports for recovery. Plasticity is higher in younger ages, but is not limited to it

Recovery after early brain injury is greater for language than for spatial skills because spacial processing is the older of the two capacities in our evolutionary history and, therefore, a more lateralized at birtth. But early brain injury has far less impact than later injury on both language and spatial skills, revealing the young brain’s plasticity

Growth of the cerebral cortext

most growth occurs here- it is the largest structure of the brain

The cerebral cortex contains most of the neurons and synapses

It is the last brain structure to stop growing

Sequence of brain development vs Quality

• Sequence of brain development is genetically programmed

• Quality of neural development is shaped by experiences

• Rich experiences from stimulation produce rich brains

Timing is important:

believe that experiences “wire” brain during the period of growth (sensitive periods)

Repeated experience helps knot neurons into ciruts

General downsides and Upsides of Early Brain Plasticity

Downsides- under stimulation can have grave consequences —> underdeveloped and smaller brains (happens to kinds who aren’t touched or played with)

Upsides- malleable early brain is more likely to recover from strokes and injuries - comprehension - early preschool programs can help overcome deficits

Does the quality of caregiving have a big effect on brain development?

YES.

Parental interactions and responses play a central role in setting up neural circuitry (e.g., playful interactions)

overstimulation can be problematic

Gross Motor Skills

control over actions that help infants get around in their environment, such as crawling, standing, and walking

Fine Motor Skills

smaller movements, such as reaching and grasping

• girls get fine motor skills before boys do (develop faster)

Infant learning: classical conditioning

A neutral stimulus is paired with a stimulus that leads to a reflexive response. Once a baby’s nervous system makes the connection between two stimuli, the neutral stimulus produces the behavior by itself

• helps infants recognize which events usually occur together in everyday learning, so they can anticipate what is about to happen next. Environment becomes more orderly and predictable

Infant learning: operant conditioning

Infants act on their environment, and the stimuli that follow their behavior change the probability that the behavior will occur again. reinforcements and punishments

Habituation - Infant Learning

a gradual reduction in the strength of a response due to repetitive stimulation. Time spent looking at the stimulus, HR, respiration rate, and brain activity may all decline, indicating a loss of interest.

Once this occurs, a new stimulus, called a recovery, comes in and returns the child to normal

• makes learning and recovery more efficient by focusing our attention on those aspects of the environment we know least about

Imitation - Infant Learning

copying the behavior of another person

Chief Findings Morelli Article

Said that culture plays a heavy role in caretaking methods

• you know the rest of the results, just recall them from your brain

Sensitive periods in brain development

Extreme deprivation results in permanent brain damage.

Varied visual experience must occur for the brain’s visual centers to develop normally. If a child is not exposed to light for 3-4 days, the areas of the brain that focus on vision degenerate.

Development during this period is highly plastic (meaning it is open to change) and it is very easy to cause deprivation to the brain if not raised right

Experience-expectant brain growth

the young brain’s rapidly developing organization, which depends on ordinary experience— opportunities to explore the environment, interact with people, and hear language and other sounds

• provides foundation for experience-dependent growth

Experience-dependent brain growth

occurs throughout our lives. Consists of additional growth and refinement of established brain structures as a result of specific learning experiences that vary widely across individuals and cultures

• e.g., reading and writing, playing computer games, weaving an intricate rug, and practicing the violin.

Romanian Orphanages study

looked at children from birth to 3 ½ years old who were transferred to families from extremely deprived Romanian Orphanages. Upon arrival, most were impaired in all domains of development. Cognitive catch-up was impressive for children before 6 months, because they attained average mental test scores in childhood and adolescence. However, children who had been institutionalized for more than the first 6 months showed serious intellectual deficits. Their test scores were improved, but still remained below average.

Sudden Infant Death Syndrome (SIDS)

The unexpected death, usually during the night, of an infant younger than 1 year of age that remains unexplained after thorough investigation.

• In industrialized nations, SIDS is the leading cause of infant mortality between 1 and 12 months, accounting for about 20 percent of these deaths in the United States.

SIDS babies usually reveal rates of prematurity and low birth weight, poor Apgar scores, and limp muscle tone. Abnormal HR and respiration and disturbances in sleep-wake activity and in REM-NREM cycles while asleep are also involved

• At the time of death, SIDS babies have a mild respiratory infection

Smoking doubles the risk of disorder (smoking before and after birth too)