Reminders. What s a Neuron? Animals at Birth. How are Neurons formed? Prenatal Neural Development. Week 28. Week 3 Week 4. Week 10.

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1 Reminders What s a Neuron? Exam 1 Thursday Multiple Choice and Short Answer Bring Scantron form and #2 pencil Includes Chapter 1- Chapter 3 BUT NOT 3.1 (We will cover this on the next test) You may use one 3 x 5 inch handwritten notecard (both sides) Dendrites Receiving end Cell Body Axon Myelin Sheath Terminal buttons Synapse Action Potential!! How are Neurons formed? Prenatal Neural Development Week 3 Week 4 Group of cells form the neural plate Neural plate folds to form the neural tube Animals at Birth Vary in maturity/immaturity at birth Amount of parental care needed Precocial Altricial Week 10 Week 28 Neurons are produced in one region of neural tube (and then migrate to proper locations) Brain has nearly all the neurons it will ever have. 1

2 Infant Reflexes Reflexes: organized inborn behaviors that occur in response to particular stimulation Grasping Sucking Rooting Stepping Moro Rhythmical Stereotypies repeated sequences of motions performed with no apparent goal Motor Milestones: Locomotion Developmental Norms Comparing Individual to Group Norms: Represent the average performance of a large sample of children of a given age Permit comparisons Must be interpreted with caution Brazelton Neonatal Behavior Assessment Scale (NBAS) 2

3 Views of Motor Development Nature argument motor development is a result of maturation Gesell and McGraw (1930s) Views of Motor Development Nurture argument Practice and specific experiences are important for motor development Cultural practices can lead to variations in motor milestones Mali mothers aid motor development Hopi and Navajo mothers slow down motor development Cross Cultural Studies Current view: Dynamic-Systems Approach Neural mechanisms Views of Motor Development Perceptual skills Motor Development Changes in body proportions Child s motivation Esther Thelen

4 Dynamic Systems Theory Motor development involves many distinct skills that are organized and reorganized over time to meet the demands of specific tasks Studies of Infant Sensory Preferences and Abilities Taste Smell Sensory Capabilities sweet sour bitter 4

5 Sight: Preferential Looking Paradigm Sight Preferential Looking Paradigm AKA visual preference paradigm Sight Preferential Looking Paradigm AKA visual preference paradigm Infants prefer: Complex patterns to simple New vs. old stimuli Mom s face to stranger s Perceiving Faces Very young infants have a preference for faces over other stimuli Prefer mom s face to others faces Infants prefer attractive faces over unattractive ones They prefer to watch moving faces vs. other moving stimuli 5

6 Sight (continued) Visual acuity= the sharpness of vision Sight (continued) Visual acuity= the sharpness of vision Visual Perception: Seeing the World Newborn s distance vision ranges from 20/200 to 20/600 By 6 months, average infant s vision is already 20/20 Sound Patterns The Cat in the Hat study Before birth: moms read the story to the fetuses twice a day After birth: Pattern of sucking determine story The Cat in the Hat or The King, the Mice, & the Cheese Babies sucked in a pattern that activated The Cat in the Hat 6

7 By 4.5 mo. can recognize own names Sound Can hear well at birth, but not as well as adults Can hear best when the pitch is in the range of human speech. Can distinguish all human phonemes better than Can distinguish musical notes & songs adults Sound Prefer Human speech to other sounds high pitched, drawn out human speech over regular speech AKA parentese, or baby talk Infant-Directed Speech Lullabies to adult music Cute Example: com/video: Changes in Adult Sensation Read about in book Basic Habituation Paradigm Habituation = A gradual decline in intensity, frequency, or duration of a response to a repeated occurrence of a stimulus. Dishabituation = recovery Visual habituation is measured with looking time Sometimes measured in other ways (see next slides) 7

8 The Visual Cliff The Visual Cliff Research Paradigm Visual Cliff The Visual Cliff Do the babies who crawl across lack depth perception? No! When 2 month olds are placed on visual cliff heart rate slows down Indicates interest (not fear) The Visual Cliff In addition to depth perception, Need to incorporate perception of depth with self-experienced action consequence Visual Cliff Video They also use social referencing 8

9 The Visual Cliff Notice the interaction amongst domains Motor development Experience with crawling Sensory-perceptual development depth perception Social Referencing social-emotional development Remember Dynamic-Systems Approach!! How is this experience shaping the brain? Do these changes become permanent? An Interesting Head Count How are Neurons formed? Neurogenesis (AKA neural proliferation) Neuron migration Neuron growth and differentiation 9

10 How Do Neurons Connect? Synaptogenesis How Do Neurons Connect? Synaptogenesis Downsizing Neuronal Death Synaptic Pruning Order of pruning: Motor & Sensory areas Language & Spatial Skills Attention & Planning What about the Myelin Sheath? Myelination Begins in 4 th month of gestation Ends?? These processes allow for Plasticity What is Brain Plasticity? Neurons Neurogenesis (proliferation) Neuron migration Neuron growth and differentiation Neuronal death Connections between neurons Synaptogenesis Synaptic pruning Growth of Myelin Sheath 10

11 What is Brain Plasticity? Plasticity (cont) Plasticity = Flexibility Experience-expectant growth Experience-dependent growth Environmental Influences on Brain Development Development of The Cerebral Cortex Plasticity Sensitive period Regions of the Cerebral Cortex Develop at different rates Examples: Auditory & Visual areas most rapidly during first year Frontal Lobe develops well into late adolescence/early adulthood 11

12 Sequential Development of the Brain Infancy Motor, visual, and auditory areas Childhood Ages 3-6: Prefrontal cortex (control of behavior) Ages 6 through puberty: Temporal & Parietal lobes (language and spatial relations areas) Sequential Development of the Brain Infancy Childhood Adolescence Gray matter 2 nd wave of myelination Emotion-processing areas A No Brainer? Use It or Lose It Brain changes Growth spurts No clear 1:1 correspondence 12

13 The Primal Teen as the teenage brain is reconfigured, it remains more exposed, more easily wounded, perhaps much more susceptible to critical and long-lasting damage than most parents and educators or even most scientists had thought. (Strauch, 2003) Sequential Development of the Brain Infancy Childhood Adolescence 2 nd wave of myelination Emotion-processing areas VIDEO: The brain of a teenage genius Adult Changes in the Brain 13