HDP 1 Midterm Review Fall 2005

1. HDP 1 Midterm ReviewFall 2005

2. Topics covered WEEK 0 Th 9/22Introduction to course(Jeff Elman, Dept. of Cognitive Science) WEEK 1 Tu, 9/27 Infancy and Evolution(Jim Moore, Dept. of Anthropology) Th 9/29 The History of Childhood(Stefan Tanaka, Dept. of History) WEEK 2 Tu 10/4 Genes, Brain Development and Behavior(Leslie Carver, Dept. of Psychology) Th 10/6 Brain Development: The Basics(Joan Stiles, Dept. of Cognitive Science)

3. WEEK 3 Tu 10/11 CLASS CANCELLED Th 10/13 Development of Visual Perception(Karen Dobkins, Dept. of Psychology) WEEK 4 Tu 10/18 Conceptual Development(Gedeon Deak, Dept. of Cognitive Science) Th 10/20 Social Development(Gail Heyman, Dept. of Psychology) WEEK 5 Tu 10/25 Autism(Aubyn Stahmer, Children’s Hospital)

4. Introduction (Elman)

5. Important terms and concepts • Maturation • Learning • Adaptation • Evolution • Emergentism • Genetic conservatism • The “Gene for X” fallacy • Nature vs. (or and?) Nurture

6. The “Gene for X” fallacy

7. Less DNA More DNA

10. Genetic conservatism

12. The power of the environment

13. from butterfly host from alderfly host Trichogramma (wasp)

14. from butterfly host from alderfly host Trichogramma (wasp)

15. Emergentism • The whole is greater than the sum of its parts • Interactions create complexity • Outcomes are not easily predictable • Multiple sources of causation • A prime example: Language

16. Infancy & evolution (Moore)

17. Important terms and concepts • Life History Theory • 5 stages of development • The “obstetric dilemma” • Bipedalism • precocial species vs. altricial species

18. very rapid growth, but rate falling fast sudden rapid growth again, then rapid fall in rate slower, even growth growth rate drops growth stops

19. INFANT (ends at weaning – 36 mos) ADOLESCENT (ends when socially & physically adult-like – 19-25 yrs) CHILD (ends at end of brain growth – 7 yrs) JUVENILE (ends at end of dependence/puberty – 10-12 yrs) ADULT

20. LIFE HISTORY THEORY “…natural selection favors organismic life cycles in which resources are allocated among growth, maintenance and reproduction in relation to age or size in a manner that maximizes the reproductive potential across individual life spans.”Pereira 1993

21. A big question • Why do humans extend the immature period?

22. Breaking it down… • What is the reproductive disadvantage of extended immaturity? • What might compensate for this disadvantage? • What does the “obstetric dilemma” refer to?

23. The obstetric dilemma • Bipedalism associated with change in pelvic structure & smaller birth canal • Evolution of humans associated with increased brain size • Energy cost for mother to continue supporting fetal brain development

24. A possible solution Be born “early”, and have an extended transition from infancy to adulthood Also: create “childhood” a. Reduced nutritional needs b. Help with caring for younger siblings c. Gets young brains into enriched environment

25. The history of childhood (Tanaka)

26. Important terms and concepts • Functional imperfection • Ages of man • John Locke (ideas about childhood) • Emile Rousseau (ideas about childhood) • Industrial Revolution (impact on childhood) • Tutelary complex • History of public education

27. History of childhood • Culturally, childhood is modern and somewhat peculiar to the U.S. • Early views on childhood: “little adults” • Later: • J. Locke: “tabula rasa” • E. Rousseau: to be protected and nurtured

28. Industrial Revolution’s effects on child labor • Factories were dangerous environments • Produced asymmetric growth & deformities • Separated children from families

29. Tutelary complex as response to • Industrial Revolution • Immigration and Migration • Public education • When? Mid-1800s • Why? Socialize the poor & working class

30. Genes, brain development, & behavior (Carver)

31. Important terms and concepts • Behavior Genetics (what is it? how does it work?) • Variation • Hereditability (as defined by Behavior Genetics) • Methods (twin studies; adoption studies) • Shortcomings and problems with B.G. • Reproductive cycle (meiosis, mitosis) • “Cross-over” events • (Do not need to know 6 phases of meiosis) • Embryogensis (what happens when, and where) • Early neural events: (see also Stiles lecture) • proliferation • Migration • differentiation

32. Behavior Genetics • Goal: • Measure how different people are, as a function of how closely they’re related • Definition of heritability • what is odd about this definition? • Shortcomings • Of twin studies • Of adoption studies

33. Basics of genetics • 22 pairs of chromosomes, plus 1 pair of sex chromomes (X-X, X-Y) • Meiosis (reproduction): • 1 cell produces 1 cell • Introduces variation • Mitosis (basic cell division): • 1 cell produces 2 cells

34. Brain development – the basics (Stiles)

35. Important terms and concepts • Basic questions: • How does such a complex organ as the brain get built? • How plastic/adaptable is the brain, in response either to damage or to abnormal experience? • Important terms: • ectoderm, endoderm, mesoderm • neural tube • proliferative zones • glial cells, neurons, radial glial cells • cell birthday • Radial Unit Hypothesis; protomap vs. protocortex hypotheses • active transport vs. passive transport; “inside-out” organization of the cortex • cortex (i.e., “cortical mantle”) • laminar organization of cortex • white matter; gray matter • “productive events”; “subtractive events”; synaptogenesis

36. The human brain Parietal Lobe Occipital Lobe Frontal Lobe Temporal Lobe

37. Corpus callosum

38. CORTEX (neurons; “gray matter”) “white matter” (axons)

39. Brain facts • Brain weight (adult and newborn) 3 lbs (adult); 0.8 lbs (newborn) • Number of neurons in cortex: 20 billion • Number of synapses: 60 trillion • Rate of early neuron growth & when greatest? 1st half of pregnancy 200,000/minute

40. 7 important stages • Development of neural plate E12 • Formation of trilaminar disk begins E15 • Formation of neural tube begins E18 • Neural tube closes (top; then bottom) E25; E27 • Ventricular zone progenitor cells start dividing (symmetrically) E28 • VZ asymmetric cell growth (neurogenesis) starts E42 • Greatest production of neurons E42-E125

42. Spina bifida Anencephaly

43. What parts of the neural tube become what parts of the brain? Ventricules: (fluid-filled) holes in the middle of the brain Ventricular zone: inner surface of hollow tube where progenitor cells lie

44. Then… • Migration • Cell’s birthday • Role of radial glial cells • “inside/out” pattern of migration • 6 cortical layers • Cell differentiation • Subtractive events

45. (eyes) (ears) Importance of experience & cell activity (auditory cortex) (visual cortex)

46. (eyes) (ears) Importance of experience & cell activity(“re-wiring the ferret” experiment) (auditory cortex) Now acts like visual cortex! (visual cortex)

47. Development of visual perception (Dobkins)

48. Important terms and concepts • Basic questions: • What are the perceptual consequences of neural changes? • How is infant vision different from adult vision? • What are the clinical implications? • Important terms: • sensitivity • threshold/contrast threshold • contrast • spatial frequency • grating stimulus • psychophysics • Snellen exam • acuity

49. Important terms and concepts • Important terms (cont’d.): • focus • luminance • chromatic • depth perception • stereopsis • binocular vision • monocular vision • photoreceptors (differences between infant and adult, shape and spacing)

50. Methods Q: how do you test adults’ vision? Q: how do you test infants’ vision? Q: what level of performance is considered the threshold? Q: what is the difference between threshold and sensitivity?