chap 23: Brain Development & plasticity

Question 1

What are the 7 steps of brain development in utero ?

Answer 1

1. Neurogenesis (cell birth)
2. Migration
3. Differentiation
4. maturation
5. Synaptogenesis
6. Pruning
7. Myelogenesis

Question 2

Describe step 1 of in utero brain development

Answer 2

• the subventricular zone is formed
• progenitor (precursor) cells are formed that well give rise to neuroblasts and glioblasts

Question 3

Describe step 1 of in utero brain development

Answer 3

Neurogenesis
- the subventricular zone is formed
- progenitor (precursor) cells are formed that well give rise to neuroblasts and glioblasts

Question 4

Describe step 2 & 3 of in utero brain development

Answer 4

Migration
- neurons migrate along glial fibers where cortical maps will bring them to a specific zone in the cortex
Differentiation
- cells become specialized

Question 5

Describe step 4 of in utero brain development

Answer 5

Maturation
- dendrites undergo arborization and branching as well as going spines
- axons begin to grow

Question 6

Describe step 5 & 6 of in utero brain development

Answer 6

Synaptogenesis
- synapses form in 5 phases throughout life
Pruning
- elimination of unnecessary synapses

Question 7

Describe step 7 of in utero brain development

Answer 7

Myelogenesis
- cells become myelinated

Question 8

What are the 3 distinct cortex developments ?

Answer 8

1. Sensorimotor cortex
2. Parietal & temporal association cortex
3. Frontal cortex

Question 9

Describe the adolescent brain development

Answer 9

• characterized by rapid synaptic pruning and new connections especially related to the frontal cortex
• hormonal changes are linked to unique brain maturation

Question 10

Why does cortical thickness decrease with age ?

Answer 10

1. neurons are pruned, and circuits become more efficient
2. white matter enlarges and pushes gray matter outwards which leads to a thinner cortex

Question 11

How would an aversive environment affect development ?

Answer 11

aversive experiences in early childhood compromise frontal lobe development and therefore increase susceptibility to disorder

Question 12

How much more likely are people with 2+ ACE’s to develop an addiction ?

Answer 12

they are 50 times more likely to have an addiction or attempt suicide

Question 13

How does maternal substance use affect development ?

Answer 13

• 7-10% of mothers use nicotine
• 10% consume alcohol
• mothers on antidepressants can affect brain devleopment

Question 14

What is the prevalence of cerebral palsy ?

Answer 14

1-2% in babies born at term
9% in babies born at 32 weeks
18% in babies born at 26 weeks

Question 15

Describe the results of the EPIPAGE study

Answer 15

study of neurodevelopment disorders studying preterm babies between 22 and 32 weeks
- half of the preterm babies who survived to 5 had a neurdevelopmental problem
- 44% prevalence when born at 24 weeks
- 26% prevalence when born at 32 weeks
- 12% prevalence when born at term

Question 16

When are the main brain growth spurts ?

Answer 16

1. from 3-10 months of age
2. ages 2-16+ in two year intervals

Question 17

How do experiences affect neurodevelopment? `

Answer 17

1. exposure to experiences forces the brain to develop necessary connections and functionality, when deprived, the brain does not develop a capacity for complex functions
2. in the absence of activity, there is a loss of synapses

Question 18

How does recovery occur in earlier brain lesions ?

Answer 18

1. changes in circuit organization
2. generation of new circuitry
3. generation of replacement neurons and glia