Neurodevelopment Part 1

Question 1

What influences behaviour?

Answer 1

Behavioural traits = evolutionary and genetic influences + environmental and social influences

Bhvr = current motivational state of the animal + previous experience

These are different perspectives

Question 2

What are the levels (processes) in the brain that lead to a particular bhvr?

Answer 2

Biological perspective = brain controls bhvr

Goes from abstract to spec.:
- Whole brain
- Brain circuits
- Brain regions
- Cells (neutrons and glia)
- Organelles (synapses/ axons)
- Protein complexes
- Proteins
- Genes

Question 3

What is the hierarchy in the organisation of the brain?

Answer 3

1. Levels = connected
2. Any manipulation at any level can change function of other levels.

Question 4

How much does a brain weigh at birth and how does this change in adulthood?

Answer 4

350g = birth

1300g = adulthood

Question 5

How many neurons and synapses are there in a mature brain?

Answer 5

85 billion neurons

Trillions of synapses

Question 6

How many neurons are born at peak neurogenesis prenatally?

Answer 6

250,000

Question 7

Name the three stages of prenatal development.

Answer 7

Germinal stage = 1-2 wks
Embryonic Stage = 3-8 wks
Fatal stage 9-38 wks

Question 8

What happens at the Germinal stage?

Answer 8

Nuclei of the egg + sperm fuse = zygote

Cleavage = cell division of zygote at 12h –> makes morula

Morula continues to divide to to form blastocyst (200-300 cells)

Question 9

What is a morula?

Answer 9

A cluster of homogenous cells

Question 10

When does the embryonic stage begin?

Answer 10

Implantation in the uterus

Question 11

What happens in the Embryonic stage?

Answer 11

Gastrualtion = the differentiation of different layers of cells within the blastocyst.

Blastocyst = embryonic disk

Uneven rate of cell development = 3 layers:
1. Ectoderm = folds itself to form neural tube (later = nervous S)
2. Mesoderm
3. Endoderm

Question 12

How is the nervous system formed?

Answer 12

At about 2 wks = start to develop the tube

Depending where the spinal cord is = differentiates accordingly (forebrain, midbrain, hindbrain) until it has the characteristics you have in an adult brain

Question 13

What is Spina bifida and how is it an example of a neural tube defect?

Answer 13

When the neural fold can’t fold at the level of the spinal cords = larger openings can lead to paralysis + limb deformity.

Small openings can be surgically corrected = prevented by folic acid supplements

1 in 1000 live births

Question 14

What is anencephaly?

Answer 14

Brain fails to develop = commonly results in stillborn

Question 15

What are the stages of brain development?

Answer 15

1. Cell birth/ Proliferation (Neurogenesis and Gliogenesis)
2. Cell migration
3. Cell differentiation and maturation
4. Synaptogenesis and synaptic pruning
5. Cell death
6. Myelination (myelogenesis)