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DEVELOPMENT OF THE NERVOUS SYSTEM:Operation Head Start

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Neurological Basis of Behavior (PSY - 610)
VU
Lesson17
DEVELOPMENT OF THE NERVOUS SYSTEM
Objective
To familiarize the students with:
·  Development of the brain: from the fertilization to the various developmental stages in-utero,
and postnatal. Cell migration, ( inside-out), cell competition, Cell death, growth Cones, Nerve
growth Factor and its role
·  Various stages of neuronal development.
·  Teratogenesis Genetic anomalies which affect development of the brain. Plasticity of the
Nervous system.
·  Development and growth (from intrauterine to neonate stages) to give an understanding of the
stages of development and the processes involved.
Development of the brain
Before we study the development of the brain it is important to understand life before birth
The process begins with the fertilization of the egg, and once fertilized this is known as a zygote. The
zygote undergoes rapid cell division and Mitosis is the process of cell division by which zygote grows
·
Zygote: After fertilization, fertilized and rapidly growing, enlarged egg travels towards the
uterus in 1st two weeks, after reaching the destination; it attaches itself to the uterus walls with
its tendrils. This is a very important linkage as it provides nurturance and nutrition which is
required for rapid growth of the zygote. This process of attachment is known as Implantation.
·
Embryo: After the successful implantation in the uterus, immense and rapid growth takes
place. This is when the embryo starts resembling human form. The amniotic sac ("bag"}
created, it is filled with amniotic fluid which protects the embryo and provides constant
temperature within the sac. The embryo is connected to the mothers systems and is dependent
on the mother through umbilical cord. Placenta is the container in which the embryo is
contained and attached to the mother. The double walled cavities of the placenta provides
support, nurturance (nutrients) needed by the embryo. This forms the placental barrier which
protects the embryo form harm and toxics.
·
Fetus: After four months of life after fertilization, the embryo develops into the fetus which is
the next stage. Now an individual with Reflexes which can be seen. The suckling and
swallowing develop halfway through the prenatal period. We also know that internal and
external stimulation affects are responded to by movements. So now we have a fetus
responsive to the environment (within the placenta).
Differentiation takes place in the germinal layers and then rapid division and multiplication of the
germinal cell layers into different types of cells takes place during these stages. The form shape and
development of the body and brain takes place following the principle of growth:
Operation Head Start. The brain and body grows in the cephalo-caudal (head to tail principle). This
means the development of the head and the brain if the first stage.
If we look at the reflexes of the neonate we see a very well documented development and progression
(of the brain and the body):
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Neurological Basis of Behavior (PSY - 610)
VU
Reflexes of the neonate
Plantar: if we stroke foot of the neonate the toes fan up and out
Rooting: If a cheek is softly touched, the newborn turns mouth towards the cheek which has been
touched.
Suckling: if an object is placed in the mouth, the newborn starts sucking placed in mouth. This is
readiness for feeding.
Moro responses: if there is a sudden noise the newborn stretches out at first then hugs itself together.
Grasping: If a round object or finger is placed against the fingers, the fingers curls around finger or rod
placed. The curling forms a very strong grip.
Other reflexes: Swimming, (remember they have been swimming through out the first 9 months in-
utero), vomiting, hiccough, sneezing, yawning, blinking normally occurs within an hour after birth.
References
1. Brown, T.S. and Wallace. (1980) P.M Physiological Psychology
Academic Press New York
2. Kalat J.W (1998) Biological Psychology Brooks/ Cole Publishing
3. Pinel, John P.J. (2003) Biopsychology (5th edition) Allyn and Bacon Singapore
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Table of Contents:
  1. INTRODUCTION:Descriptive, Experimental and/ or Natural Studies
  2. BRIEF HISTORICAL REVIEW:Roots of Behavioural Neurosciences
  3. SUB-SPECIALIZATIONS WITHIN THE BEHAVIORAL NEUROSCIENCES
  4. RESEARCH IN BEHAVIOURAL NEUROSCIENCES:Animal Subjects, Experimental Method
  5. EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR:Species specific
  6. EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR:Decent With Modification
  7. EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR:Stereoscopic vision
  8. GENES AND EXPERIENCE:Fixed Pattern, Proteins, Genotype, Phenotypic
  9. GENES AND EXPERIENCE:Mendelian Genetics, DNA, Sex Influenced Traits
  10. GENES AND EXPERIENCE:Genetic Basis of behavior, In breeding
  11. GENES AND EXPERIENCE:Hybrid vigor, Chromosomal Abnormalities
  12. GENES AND EXPERIENCE:Behavioral Characteristics, Alcoholism
  13. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION
  14. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION:Activating brain
  15. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION:Macro electrodes
  16. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION:Water Mazes.
  17. DEVELOPMENT OF THE NERVOUS SYSTEM:Operation Head Start
  18. DEVELOPMENT OF THE NERVOUS SYSTEM:Teratology studies, Aristotle
  19. DEVELOPMENT OF THE NERVOUS SYSTEM:Stages of development, Neurulation
  20. DEVELOPMENT OF THE NERVOUS SYSTEM:Cell competition, Synaptic Rearrangement
  21. DEVELOPMENT OF THE NERVOUS SYSTEM:The issues still remain
  22. DEVELOPMENT OF THE NERVOUS SYSTEM:Post natal
  23. DEVELOPMENT OF THE NERVOUS SYSTEM:Oxygen level
  24. Basic Neuroanatomy:Brain and spinal cord, Glial cells, Oligodendrocytes
  25. Basic Neuroanatomy:Neuron Structure, Cell Soma, Cytoplasm, Nucleolus
  26. Basic Neuroanatomy:Control of molecules, Electrical charges, Proximal-distal
  27. Basic Neuroanatomy:Telencephalon, Mesencephalon. Myelencephalon
  28. Basic Neuroanatomy:Tegmentum, Substantia Nigra, MID BRAIN areas
  29. Basic Neuroanatomy:Diencephalon, Hypothalmus, Telencephalon, Frontal Lobe
  30. Basic Neurochemistry:Neurochemicals, Neuromodulator, Synaptic cleft
  31. Basic Neurochemistry:Changes in ionic gates, The direct method, Methods of Locating NT
  32. Basic Neurochemistry:Major Neurotransmitters, Mesolimbic, Metabolic degradation
  33. Basic Neurochemistry:Norepinephrine/ Noradrenaline, NA synthesis, Noadrenergic Pathways
  34. Basic Neurochemistry:NA and Feeding, NE and self stimulation: ICS
  35. Basic Neurochemistry:5HT and Behaviors, Serotonin and sleep, Other behaviours
  36. Basic Neurochemistry:ACH and Behaviors, Arousal, Drinking, Sham rage and attack
  37. Brain and Motivational States:Homeostasis, Temperature Regulation, Ectotherms
  38. Brain and Motivational States:Biological Rhythms, Circadian rhythms, Hunger/Feeding
  39. Brain and Motivational States:Gastric factors, Lipostatic theory, Neural Control of feeding
  40. Brain and Motivational States:Resting metabolic state, Individual differences
  41. Brain and Motivational States:Sleep and Dreams, Characteristics of sleep
  42. Higher Order Brain functions:Brain correlates, Language, Speech Comprehension
  43. Higher Order Brain functions:Aphasia and Dyslexia, Aphasias related to speech
  44. Higher Order Brain Functions:Principle of Mass Action, Long-term memory
  45. Higher Order Brain Functions:Brain correlates, Handedness, Frontal lobe