1. CHELSEA A. IENNARELLA ANS 536 – PERINATOLOGY SPRING 2014 Central Nervous System Development

2. ANS 536 - Perinatology - CNS Development

3. Overview: Prenatal CNS Development  Period of the Ovum  Period of the Embryo  Period of the Fetus Post-Natal CNS Development Male vs. Female Brain Lecture 03/26/2014: Epigenetic Changes CNS Abnormalities Species Differences in CNS Development and Physiology ANS 536 - Perinatology - CNS Development

4. Prenatal Growth & Development: ANS 536 - Perinatology - CNS Development Period of the Ovum:  fertilization through implantation Period of the Embryo:  gastrulation through establishment of all major organ systems Period of the Fetus:  maturation of organ systems through birth

5. ANS 536 - Perinatology - CNS Development Period of the Ovum:

6. ANS 536 - Perinatology - CNS Development From the time of fertilization until implantation (GW 0-1).  Little or no increase in weight of embryo.  Characterized by reductive cell divisions; hyperplasia.

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9. Period of the Embryo:

10. ANS 536 - Perinatology - CNS Development From gastrulation through the establishment of all major organ systems (GW 2-15).  Formation of specific organs and tissues occurs.  All major structures and organ systems are established; heart and circulatory system can be considered functional.  Growth mostly resulting from hyperplasia.

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13. Human Development Video: ANS 536 - Perinatology - CNS Development http://www.youtube.com/watch?v=UgT5rUQ9EmQ

14. CNS Development: ANS 536 - Perinatology - CNS Development CNS development begins during the 3 rd gestational week in humans.  Most rapid CNS development occurs during the 24 th gestational week.  Brain is not fully developed until adulthood (early 20’s).

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16. Neurulation: ANS 536 - Perinatology - CNS Development transformation of the neural plate into the neural tube

17. Neural Tube Formation: ANS 536 - Perinatology - CNS Development neural plate: a thickened plate of ectoderm that gives rise to the neural tube and crests notochord: flexible rod- shaped structure, derived from the mesoderm, that supports the primitive axis of the embryo

18. Neural Tube Formation: ANS 536 - Perinatology - CNS Development neural crest: transient, multipotent, migratory cell population  Cells contribute to many different systems including peripheral nervous systems, skin, skeletal, adrenal glands, and GI tract

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21. Period of the Fetus:

22. ANS 536 - Perinatology - CNS Development From maturation of organ systems through birth (GW 16-38).  Characterized by a large increase in weight and large increase in nutrient demand.  Growth is mostly resulting from hypertrophy.

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24. prosencephalon: forebrain mesencephalon: midbrain rhombencephalon: hindbrain

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27. telencephalon: mature cerebrum diencephalon: thalamus, hypothalamus, pituitary mesencephalon: midbrain metencephalon: pons and the cerebellum myelencephalon: medulla oblongata

28. Development of the Embryonic Brain: ANS 536 - Perinatology - CNS Development http://www.youtube.com/watch?v=mMDPP-Wy3sI

29. ANS 536 - Perinatology - CNS Development Post-Natal CNS Development

30. Post-Natal Brain Development: ANS 536 - Perinatology - CNS Development Infant’s brain is roughly 25% of its adult size at birth.  75% developed by one year of age  80-90% developed by three years of age Full maturation does not occur until adulthood in humans (roughly 20-25 years old).

31. ANS 536 - Perinatology - CNS Development Developmental Structures of Importance

32. Limbic System: ANS 536 - Perinatology - CNS Development Collection of several structures located in the inner brain beneath the cortex.  prefrontal cortex  hypothalamus  amygdala  hippocampus

33. Prefrontal Cortex: ANS 536 - Perinatology - CNS Development Location of most advanced cognitive function  Attention, motivation, goal-directed behavior Last area of the brain to mature  Undergoes important developmental changes even into adolescence

34. Hypothalamus: ANS 536 - Perinatology - CNS Development Regulation of stress response by signaling the pituitary to secrete ACTH  stimulates secretion of stress hormone, cortisol, from adrenal cortex  stimulates secretion of adrenaline from the adrenal medulla

35. Amygdala: ANS 536 - Perinatology - CNS Development Evaluates threats and triggers the body’s response to stress  Allows for generation of learned emotional responses to a variety of situations

36. Hippocampus: ANS 536 - Perinatology - CNS Development Memory formation and spatial learning.  Declarative memory; the memory of facts or events  Important in recognition

37. Synapses & Neurons: ANS 536 - Perinatology - CNS Development The brain processes information by forming networks of neurons.  Communicate using electrical and chemical signals. Messages are passed between neurons at connections called synapses.

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39. Synaptic Pruning: ANS 536 - Perinatology - CNS Development For first three years of life, a child’s brain has roughly twice as many synapses and an adult.  Synapses used frequently become stronger.  Synapses rarely used are more likely to be eliminated.

40. Brain Development Video: ANS 536 - Perinatology - CNS Development http://www.youtube.com/watch?v=mMDPP-Wy3sI

41. Continued Brain Development: ANS 536 - Perinatology - CNS Development During the second year of life, the brain’s language center develops more synapses and becomes more interconnected  Vocabulary often quadrupled during this time. Rapid increase in rate of myelination. Emotional awareness and self awareness develop.

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43. Pinky & the Brain: ANS 536 - Perinatology - CNS Development Nature vs. Nurture  Genes lay foundation for brain but final wiring is caused by an environmental effect Laboratory mice are virtually genetically identical.  Dramatic difference seen in IQ

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45. Differences Between Male & Female Developing Brain

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47. Differences During Embryonic Development: ANS 536 - Perinatology - CNS Development Differences seen as early as GW 26  Thickening of CC in females that remained post birth Males outperformed females on motor and spatial cognitive tasks; females were faster in tasks of emotion identification and nonverbal reasoning (Satterthwaite et al. 2014)

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49. Overview: ANS 536 - Perinatology - CNS Development CNS development begins in utero and continues into adulthood. Several transient structures undergo morphological and functional changes to give rise to a more mature system. Interaction between genetics and environment determine final CNS capacity and functionality.

50. Next Lecture: ANS 536 - Perinatology - CNS Development Epigenetic Changes Effecting the CNS CNS Abnormalities Species Differences in CNS Development and Physiology

51. Questions: ANS 536 - Perinatology - CNS Development