Download The Development of the Nervous System: Stages, Influences, and Teratogenic Effects and more Lecture notes Neurological Basis of Behavior in PDF only on Docsity! Neurological Basis of Behavior (PSY610) VU Lesson 23 DEVELOPMENT OF THE NERVOUS SYSTEM Objectives: These lessons would familiarize the students with • The stages of development of the brain and the changes which takes place • Various stages of neuronal development. • Development of the brain: from the fertilization to the various developmental stages in- utero, and postnatally. • Cell differtiation, determination, migration, (inside-out), cell competition, Cell death, growth Cones, Nerve growth Factor and its role, Influences in growth and development of the brain • Teratogenesis Genetic anomalies which affect development of the brain. • Plasticity of the Nervous system. Main Purpose: This module would take the students through the development and growth (from intrauterine to neonate stages) to give an understanding of the stages of development and the processes involve. In the last lesson we discussed some of the influences which can affect normal brain development, we would continue on the same topic • Oxygen level: oxygen is very important for the brain cells during growth as well as throughout life. As the embryo depends on the mother for its oxygen supply, any reduction in the normal level would affect the growing brain. If the mother is not getting enough oxygen during last trimester, this leads to hypoxia (low oxygen levels) of the fetus. If the mother’s blood circulation is faulty, then it would lead to damage of the brain areas which may have developed normally, (anemia, and heart disorders in mothers’ leads to this problem). This damage is similar to that of mental retardation. Why? Because neurons die off and lesser number of cells remains leading to deficient functioning of these areas. • Prenatal motor activity: This is important as there is evidence if there increased activity in uterus this leads to stronger muscles. This is exercising muscular connection, and their pathways. Thus motor connections are strengthened even within utero. Not just motor exercises, but sensory responses are also there. Evidence has shown that the embryo/fetus responds to mother’s lullabies and voice. Those fetuses which are stimulated during the prenatal period are more alert when they are born. • Drugs: Though the placental barrier protects the embryo, there are some substances which manage to pass through the protective membranes. It was discovered in the 1960’s that drugs affect the normal growth of the fetus, leading to serious deformities. Thalidomide was the first drug to have been identified to have teratogenic effects. This sedative was given to expecting mothers in the 1st three months; it caused major deformities in the growing embryo. Similarly, morphine, heroin, alcohol, nicotine, cocaine and tobacco also affect the embryo. Mothers are warned against taking these or other pharmaceutical substances during pregnancy teratogenic effects • External Stimulation: This is very important for the growing embryo. Unless external stimulation is received the organs and muscles do not develop normally. Therefore sensory ©Copyright Virtual University of Pakistan 83 docsity.com
