Lecture 5

Question 1

What develops 16 weeks after fertilization?

Answer 1

cerebral expansion and commissures

prosencephalon develops dramatically

Question 2

What develops 3 months after fertilization?

Answer 2

basic structures established

Question 3

What develops 5 months after fertilization?

Answer 3

CNS myelination begins

Question 4

What develops 7 months after fertilization?

Answer 4

lobed cerebrum

Question 5

What develops 9 months after fertilization?

Answer 5

gyri and sulci

Question 6

What do cells have to do during development?

Answer 6

migrate
differentiate
become defined

Question 7

What are commissures?

Answer 7

Connections between the brain and the heart

Question 8

What are the composition changes in myelin?

Answer 8

galactolipids and protein compounds increase

Question 9

When does myelin form?

Answer 9

5 months post fertilization in humans

10 days post fertilization in rats

Question 10

How much “body weight” do oligodendrocytes produce perday?

Answer 10

3 times

Question 11

When does myelination stop?

Answer 11

Most over by two years but some in late teens (in neocortex)

Question 12

When are critical periods of development and how were they found?

Answer 12

6th week, 9th week, 5th to 10th weeks

Rubella infection

Question 13

What abnormalities occur if the fetus is infected with rubella before the 6th week?

Answer 13

Eye malformations e.g. cataract

Question 14

What abnormalities occur if the fetus is infected with rubella before the 9th week?

Answer 14

Deafness (organ of corti)

Question 15

What abnormalities occur if the fetus is infected with rubella before the 5th to 10th week period?

Answer 15

Cardiac malformalities

Question 16

What disorders can form in the second trimester?

Answer 16

CNS disorders

Question 17

When does the risk of abnormalities fall?

Answer 17

16 weeks

Question 18

Why is the fetus susceptible to fetal alcohol syndrome?

Answer 18

Alcohol causes placenta
Fetus doesn’t clear alcohol well
Fetal levels higher

Question 19

What are major symptoms of fetal alcohol syndrome?

Answer 19

facial abnormalities
microcephaly
loss of cells
loss of fibers e.g. callosal agenesis
Disturbed migration
Irritability - neurons are more excitable
Motor and intellectual impairment

Question 20

Name two examples of drugs of abuse and disorders that can be caused by them

Answer 20

Opiates
- neonatal withdrawal
Cocaine 
- hypoxia, abortion, withdrawal, cognition
Ecstasy
- long-term FX on hippocampus, other FX certain
Cannabis
- long-term cognitive FX

Question 21

What animal model was used to study drugs of abuse?

Answer 21

rhesus monkeys

Question 22

Whereabouts of the brain does cocaine affect?

Answer 22

Where mitosis occurs

Question 23

What is the speed of conduction during the neonatal period?

Answer 23

20-25 m/s

Question 24

What is the speed of conduction during the first six months after birth?

Answer 24

32-50 m/s

Question 25

What is the speed of conduction during the 6th to 12th month after birth?

Answer 25

33-60 m/s

Question 26

What is the speed of conduction from the 12th to 24th month after birth?

Answer 26

40-60 m/s = adult speed

Question 27

Why is it important to discuss when the fetus starts to feel pain?

Answer 27

- Increasing use of interventional procedures and abortion debate - Sentient conscious aspect of independent human - Difficult to come to a conclusion; series of effects need to happen for the possibility to feel pain - Somatosensory input

Question 28

What can be the "series of effects" that need to happen for the possibility of pain?

Answer 28

Receptors must connect to the PNS/hypothalamus to relay signals Connections and structures must be present

Question 29

What are examples of somatosensory input?

Answer 29

Pain requires connection of receptors, sensory neurons, thalamasu and cortex

Question 30

When does innervation of dermal skin and subdermal skin happen?

Answer 30

dermal: 28 weeks subdermal: 6-8 weeks

Question 31

What happens from 8 weeks?

Answer 31

DRG connection (non-noxious)

Question 32

What happens from 19+ weeks?

Answer 32

C-fiber (noxious stimuli) connection

Question 33

When does reflex response to noxious stimuli happen in preterm infants?

Answer 33

23 weeks

Question 34

Is a reflex response a conscious perception of pain?

Answer 34

no

Question 35

What happens from 28 weeks?

Answer 35

facial responses to heel lancing

Question 36

Is a sub-plate considered a cortex?

Answer 36

No; it is a developing cortex

Question 37

The organized thalamus forms when?

Answer 37

8+weeks

Question 38

When do retinal inputs arrive?

Answer 38

14-16 weeks

Question 39

What happens at 25 weeks?

Answer 39

Myelination

Question 40

What happens at 24 weeks?

Answer 40

Connections from the thalamus to cortex form.

Question 41

When do evoked potentials in the cortex form?

Answer 41

From 29 weeks or earlier

Question 42

What do recent studies suggest when finding the beginning period of pain?

Answer 42

24 weeks because cortical responses have been found

Question 43

What are well-developed at birth?

Answer 43

taste, smell, hearing

Question 44

Is there a difference between bottle-fed and breast-fed babies?

Answer 44

Breast-fed babies can differentiate between their mother and other woman's breast pads while bottle-fed babies prefer any lactating female

Question 45

From what period can babies locate sounds?

Answer 45

3 days

Question 46

From when do the eyes become vision-sensitive?

Answer 46

7 months

Question 47

Are the optic nerves myelinated at birth?

Answer 47

no

Question 48

When does vision become sharper?

Answer 48

6 months?

Question 49

Why does vision become sharper overtime?

Answer 49

Development of ocular dominance columns

Question 50

When is color vision considered to be good?

Answer 50

2 months

Question 51

Where do babies writhe?

Answer 51

E28-32

Question 52

Name 7 examples of postnatal reflexes?

Answer 52

``` Moro (startle) complex Stepping Palmar grasp Swimming Babinski reflex Rooting Sucking ```

Question 53

What is the moro complex?

Answer 53

baby supine - remove head support trunk extension cycle of limb extension (adbuction from midline) and limb flexion (adduction to midline)

Question 54

When does the moro complex go away?

Answer 54

after 3 months

Question 55

What is stepping?

Answer 55

Holding up feet onto surface

Question 56

When does stepping go away?

Answer 56

After 6 weeks

Question 57

What is the Palmar Grasp?

Answer 57

May support own weight and is involved in the development of inhibition

Question 58

When does the palmar grasp go away?

Answer 58

3-4 months

Question 59

Does swimming happen in all babies?

Answer 59

no

Question 60

When does swimming go away?

Answer 60

After 4-6 months

Question 61

What is the Babinski-reflex?

Answer 61

Neonates fan toes when sole is stroked?

Question 62

What happens to the Babinski reflex as an adult?

Answer 62

Adults curl their toes instead of fanning

Question 63

What happens to adults with descending motor tract damage?

Answer 63

Adults start to fan toes

Question 64

What are examples of descending motor tract damage causes?

Answer 64

MS, spinal cord damage

Question 65

What is rooting?

Answer 65

When the baby opens the mouth and moves the head about for nipple seeking after their cheek is stroked

Question 66

When does rooting go away?

Answer 66

after 4-7 months

Question 67

What are examples of co-ordinated responses post birth?

Answer 67

reaching | language development

Question 68

When does reaching start?

Answer 68

5 months old

Question 69

When do babies start to attain objects from reaching?

Answer 69

8-9 months old

Question 70

When do infants start to sow adult motor patterns?

Answer 70

2 years old