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Central Nervous System Development. Chelsea A. Iennarella ANS 536 – perinatology Spring 2014. 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
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Central Nervous System Development Chelsea A. Iennarella ANS 536 – perinatology Spring 2014
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
Prenatal Growth & 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 ANS 536 - Perinatology - CNS Development
Period of the Ovum: ANS 536 - Perinatology - CNS Development
Period of the Ovum: • From the time of fertilization until implantation (GW 0-1). • Little or no increase in weight of embryo. • Characterized by reductive cell divisions; hyperplasia. ANS 536 - Perinatology - CNS Development
Period of the Embryo: ANS 536 - Perinatology - CNS Development
Period of the Embryo: • 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. ANS 536 - Perinatology - CNS Development
Human Development Video: http://www.youtube.com/watch?v=UgT5rUQ9EmQ ANS 536 - Perinatology - CNS Development
CNS Development: • CNS development begins during the 3rd gestational week in humans. • Most rapid CNS development occurs during the 24th gestational week. • Brain is not fully developed until adulthood (early 20’s). ANS 536 - Perinatology - CNS Development
Neurulation: • transformation of the neural plate into the neural tube ANS 536 - Perinatology - CNS Development
Neural Tube Formation: 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 ANS 536 - Perinatology - CNS Development
Neural Tube Formation: • neural crest: transient, multipotent, migratory cell population • Cells contribute to many different systems including peripheral nervous systems, skin, skeletal, adrenal glands, and GI tract ANS 536 - Perinatology - CNS Development
Period of the Fetus: ANS 536 - Perinatology - CNS Development
Period of the Fetus: • 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. ANS 536 - Perinatology - CNS Development
prosencephalon: forebrain • mesencephalon: midbrain • rhombencephalon: hindbrain ANS 536 - Perinatology - CNS Development
telencephalon: mature cerebrum • diencephalon: thalamus, hypothalamus, pituitary • mesencephalon: midbrain • metencephalon: pons and the cerebellum • myelencephalon: medulla oblongata ANS 536 - Perinatology - CNS Development
Development of the Embryonic Brain: http://www.youtube.com/watch?v=mMDPP-Wy3sI ANS 536 - Perinatology - CNS Development
Post-Natal CNS Development ANS 536 - Perinatology - CNS Development
Post-Natal Brain 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). ANS 536 - Perinatology - CNS Development
Developmental Structures of Importance ANS 536 - Perinatology - CNS Development
Limbic System: • Collection of several structures located in the inner brain beneath the cortex. • prefrontal cortex • hypothalamus • amygdala • hippocampus ANS 536 - Perinatology - CNS Development
Prefrontal Cortex: • 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 ANS 536 - Perinatology - CNS Development
Hypothalamus: • 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 ANS 536 - Perinatology - CNS Development
Amygdala: • Evaluates threats and triggers the body’s response to stress • Allows for generation of learned emotional responses to a variety of situations ANS 536 - Perinatology - CNS Development
Hippocampus: • Memory formation and spatial learning. • Declarative memory; the memory of facts or events • Important in recognition ANS 536 - Perinatology - CNS Development
Synapses & Neurons: • The brain processes information by forming networks of neurons. • Communicate using electrical and chemical signals. • Messages are passed between neurons at connections called synapses. ANS 536 - Perinatology - CNS Development
Synaptic Pruning: • 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. ANS 536 - Perinatology - CNS Development
Brain Development Video: http://www.youtube.com/watch?v=mMDPP-Wy3sI ANS 536 - Perinatology - CNS Development
Continued Brain 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. ANS 536 - Perinatology - CNS Development
Pinky & the Brain: • 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 ANS 536 - Perinatology - CNS Development
Differences Between Male & Female Developing Brain ANS 536 - Perinatology - CNS Development
Differences During Embryonic 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) ANS 536 - Perinatology - CNS Development
Overview: 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. ANS 536 - Perinatology - CNS Development
Next Lecture: Epigenetic Changes Effecting the CNS CNS Abnormalities Species Differences in CNS Development and Physiology ANS 536 - Perinatology - CNS Development
