1 Psychology 304: Brain and Behaviour Lecture 20

2 The Endocrine System and Development of the Nervous System 1.What are examples of disorders that result from excessive or deficient hormone levels? (continued) 2. What are the phases of prenatal neurodevelopment?

3 By the end of today’s class, you should be able to: 1. describe the causes and symptoms of disorders associated with endocrine abnormalities. 2. review the process of neural tube development. 3. describe the mechanisms associated with cell migration.

4 What are examples of disorders that result from excessive or deficient hormone levels? (continued) Examples of disorders resulting from endocrine abnormalities include the following:

5 Psychosocial Dwarfism

6 Cushing’s Disease

7 Cushing’s Syndrome

8 Congenital Adrenal Hyperplasia

9 What are the phases of prenatal neurodevelopment? Prenatal neurodevelopment is marked by a number of discrete phases:

10 1. Development of the neural plate and neurogenesis.  Within 1 week of conception, the embryo shows three cell layers: The ectoderm, mesoderm, and endoderm.  The nervous system develops from the neural plate, which is evident 3 weeks after conception.

11 Formation of Neural Tube Develops into the PNS.

12 Electron Micrograph of Neural Tube Closure

13 Electron Micrograph of Neural Tube Closure

14 Neural Tube

15 Embryonic Neural Tube Development

16  The anterior end of the neural tube ultimately develops into the forebrain, midbrain, and hindbrain.  The posterior end of the neural tube ultimately develops into spinal cord.  Once formed, the cells that line the inner surface of the neural tube—that is, the ventricular zone—divide and proliferate.

17 Forebrain Midbrain Hindbrain Spinal cord CNS Development from the Neural Tube

18 2. Cell migration  Once cells have developed in the ventricular zone, they migrate to target locations.  Migration occurs in two directions: radial migration and tangential migration.

19 Directions of Migration

20 The Endocrine System and Development of the Nervous System 1.What are examples of disorders that result from excessive or deficient hormone levels? (continued) 2. What are the phases of prenatal neurodevelopment?