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Ch 5

Ch 5. Biosocial development: First two years. Early Physical Development. Principles of Development. Cephalocaudal principle: principle that development proceeds in a head-to-tail direction, upper parts of body develop before lower parts

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Ch 5

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  1. Ch 5 Biosocial development: First two years.

  2. Early Physical Development • .

  3. Principles of Development • Cephalocaudal principle: principle that development proceeds in a head-to-tail direction, upper parts of body develop before lower parts • Proximodistal principle: development proceeds from within to without, parts near enter develop before extremities

  4. Patterns of Growth • Boys tend to be larger than girls • 23 lbs by year , 31.5 by year 3 • Teething at 3-4 months • By 1stbday usually have between 6-8 teeth • Genetic influences interact with environment • Nutrition: benefits of breast feeding • Other nutritional concerns

  5. Sleep

  6. Sleep • Average newborn sleeps 16 hours/day • Baby to baby variability in timing, rhythmicity, duration is common. • Ample sleep correlates with normal brain maturation, learning, emotional regulation, academic success and psychological adjustment

  7. Sleep Dynamic systems of sleep in babies: Interacting factors: • Genes • Brain development • Prenatal development • Parental behaviors/characteristics/experiences • Culture • Etc…

  8. Sleep Dysregulated babies and parents: • A two way street- • Both must adjust • With responsiveness.

  9. Sleep • Early Brain development • Connections • Basic Brain structures (what develops when- Also, see "prefrontal cortex" on p. 132) • Fusiform face area (also read "seeing:" p.136) • Transient exuberance & pruning • axon, dendrite, & synapse • Experience and the brain • Stress and the brain • Experience expectant brain development • Experience-dependent brain development • self-righting • Shaken baby syndrome • Early reflexes • Gross motor skills • Fine motor skills

  10. Early brain development: driven by nature- sculpted by “nurture.” Some Brain structures: • Frontal lobe: decision-making, emotional self-regulation, attention • Sensory cortex: • Auditory, Visual, Somatosensory(body moving and sensing) • Brain stem: basic life support/instinct • Digestion, breathing, heart rate, sleep/wake

  11. The Brain and Reflex Behavior • Central nervous system: what makes it up? • Sensory messages travel to the brain ad the brain sends motor commands back • At birth1/4-1/3 size of adult brain, by 6=1/2…growth occurs in fits and starts; Brain growth spurts • Initially, 3 weeks after conception the brain begins to take form as a tube and eventually a spherical mass of cells

  12. BRAIN • By birth, spurt of spinal cord and brain stem has run its course • Cerebellum grows fastest during first year of life • Cerebrum- largest part of the brain, divided into left and right half • Specialization of the hemispheres – laterilization, left? Right? • Corpus callosum joins the hemispheres: share info coordinate commands • Each cerebral hemisphere has four lobes • Cerebral cortex: outer surface of cerebrum

  13. Areas of the Cortex

  14. Brainstem well mature before birth. Cortex for senses/movementmatures next (after birth). Cortex for self-regulation matures later. Concept: Development occurs first in the areas for basic functions- (breathing, smelling, reflexes…) later for advanced functions (remembering, language, self-regulation…) (bottom to top- back to front, low to high, primitive to sophisticated, can’t build a house from the roof down!)

  15. Each “part” of the brain has a job (or many) to do. • Some are very specific! Example: • Fusiform face area: • Specially dedicated to face perception and face reading. • Tuned to seeing faces (genetically programmed to prefer looking at faces than inanimate objects) • Trained by seeing faces (experience seeing animated faces promotes good person and emotion recognition). • Infants can start seeing faces on day 1. • Infant vision = 4 to 30 inches.

  16. Fusiform face area: Why that is cool: • Adults talk to babies- make faces. • What are babies designed to do? • BOTH are genetically (evolutionarily) mediated species-typical behaviors. • Just like breast feeding- • “face feeding?” • Human language- • Social skills training….

  17. BRAIN cells • Neurons and glial ells • 2nd month of gestation 250,000 neurons produced per minute • Most neurons are in place in the cortex by 20th week of gestation and structure becomes well-defined by 32nd • Once in place neurons sprout axons and dendrites • Integration, Differentiation, Cell death • Born with 100 Billion Neurons, all you will ever have, if you decide to keep them  (…or is it????)

  18. BRAIN cells in recent research • Recently neurogenesis was shown to continue in several small parts of the brain of mammals: the hippocampus and the subventricular zone. Studies have indicated that hormones, such as testosterone in vertebrates and ecdysone in invertebrates, have an influence on the rate of neurogenesis. • evidence that hippocampal adult neurogenesis is important for learning and memory • Studies have linked neurogenesis to the beneficial actions of specific antidepressants, suggesting a connection between decreased hippocampalneurogenesis and depression • Sleep reduction and decreased neurogenesis study

  19. Micro- level development: Neuron = communication cell in the brain. • Soma = cell body • Axon: long arm extending from soma- only one/neuron (they can split and branch) • Dendrite: Many ‘branch’ like arms extend from soma.

  20. Connections in the Brain

  21. Synapse: • The GAP between the axon terminal and the dendrite of a neighboring neuron. • When someone says “brain connection” they mean “synapse.” • Neurotransmitters are ‘shot” across the gap from axon to dendrite.

  22. Connections in the Brain

  23. At birth infant has 100+ billion neurons. (billions more than you.) Two processes occur: • Pruning: Neurons die, dendrites“pruned” (like a garden): lifelong • New connections form • As many as 15,000 new synapses/neuron by 1 year. • Called transient exuberance = (short-lasting rapid increase in connectivity). Two factors guide the process: • Genes and • “Use it or lose it”

  24. BRAIN • Myelination: process of coating neural pathways with fatty substance (myelin) that enables faster communication between cells • Begins halfway through gestation • Myelination of sensory pathways and motor pathways before birth in the spinal cord and after birth in the cerebral cortex may account for appearance and disapearance of early reflexes • Early reflexes: controlled by lower brain, 27 primitive reflexes, Moro reflex • Postural reflexes, locomotorrelfexes • Reflexes that persist of the early reflexes have protective value; reflect shift to voluntary behavior

  25. Experience and the brain Early experiences can affect child brain - can last into adulthood. e.g. early stress maydysregulate the “stress response system” in brain- • Faster/stronger stress responses- (hypervigilant and aggressive) Or • slower/weaker stress response (flattened emotions/depressed/timid) May contribute to future mental illness See “orphans”

  26. If a brain requires a stimulus in order to develop a certain function it is called an “experience expectant” brain function. An infant’s ability to perceive a certain sound in the language of her parents is part of experience dependent brain development. Experience expectant brain development: • Experiences that are universal for humans • Experiences necessary for normal brain development. e.g. lightmust stimulate retina and neural impulses must reach visual cortex for vision to occur. Note: It is extremely rare for infant brains to not get the experiences they expect. Light, sound, touch, movement etc.

  27. Experience-dependent: • Experiences that might happen • Different from person to person, family to family, culture to culture… • The brain changes in response-

  28. Experience-dependent: Language: • You Might hear English, or you MIGHT hear Swahili, or you MIGHT hear Mandarin…. • Brain/language system “tunes” to parent’s language WHY? social interactions: • You MIGHT be in a really quiet, subdued family, or you MIGHT be in a loud, expressive family, or you MIGHT be in a stressful, unpredictable family: • Brain/social systems “tune” to emotional environment

  29. Experience-dependent = plasticity. • Shaken baby syndrome-rupture blood vessels and break neural connections • Self-righting- inborn drive to remedy any deficit that may occur • last of brain to mature PFC, plays important role in planning, impulse control, self-regulation etc. PFC has own sequense of growth

  30. Immediate Consequences: • Breathing may stop or be compromised • Extreme irritability • Seizures • Limp arms and legs or rigidity/posturing • Decreased level of consciousness • Vomiting; poor feeding • Inability to suck or swallow • Heart may stop • Death

  31. Long-Term Consequences: • Learning disabilities • Physical disabilities • Visual disabilities or blindness • Hearing impairment • Speech disabilities • Cerebral Palsy • Seizures • Behavior disorders • Cognitive impairment • Death

  32. WHY? Why does this not happen to me (as easily) if I am shaken?

  33. WHY? • Babies' heads are relatively large and heavy, making up about 25% of their total body weight. Their neck muscles are too weak to support such a disproportionately large head. • Babies' brains are immature and more easily injured by shaking. • Babies' blood vessels around the brain are more susceptible to tearing than older children or adults.

  34. Sensation and Perception • Sensation (detection of a stimulus) more developed…why? • Perception (making sense of a stimulus) • One is apparent, one is dependent on experience

  35. Early senses- Touch first to develop in utero Hearing is acute Vision • Newborn focus = 4 to 30 inches • Same distance as mom’s face when breastfeeding! • In the first three months infants “learn” to focus on face expression, important face features.

  36. Fusiform face area • An area of the brain specifically for face- recognition. • Face-emotion recognition is extremely important. • Experience dependent development- • Neglect in this training can lead to impairments in social skills.

  37. Early reflexes: (see p. 133) Reflex (involuntary response) • Breathing- (also clearing airways) • Temperature (shivering, crying, etc.) • Feeding (sucking, rooting, swallowing, and everyone’s favorite- barfing!) Note: Infants gain more control as frontal lobe develops.

  38. True or false The brain grows many more neurons after birth. F The brain grows many more dendrites and makes more connections after birth. T Connection = synapse T Synapse = gap between axon to dendrite T Babies have more neurons than adults. T

  39. True or false Babies have more synapses than adults. F Once a synapse is formed, it never goes away. F Synapses are formed based on BOTH genes and experience. T Pruning includes the death of neurons. T Pruning is bad and should be avoided. F “Use it or lose it” refers to both pruning, synaptogenesis and plasticity. T

  40. Gross motor skills: = • “Gross” means “big” • Walking, kicking, reaching. Fine motor skills = • “Fine” means “Small” • Finger skills Gross develop much earlier than fine. • Gross M.S. develop in the same ORDER in almost all babies. • Gross M.S. develop with different timing in most babies. • Genes drive this development more than environment.

  41. Gross Motor Skills

  42. Surviving in Good Health

  43. True or false If a brain requires a stimulus in order to develop a certain function it is called an “experience expectant” brain function. T An infant’s ability to perceive a certain sound in the language of her parents is part of experience dependent brain development. T Most babies start to walk at the same month of development. F Most babies sit up before crawling. T

  44. Gross motor skills refers to major body movements see p. 134, table 5.1 Note skill sequence is the uniform, timing is highly variable. Fine motor skills usually refers to hand skills. • Grasping, pulling, poking etc. (More later) Note: hand movement development and early COGNITIVE development are closely linked.

  45. Malnutrition: 25 to 30 % of world’s children • Long term can impair brain development • also • Susceptible to disease

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