Oct. 23: Development

Question 1

Lissencephaly

Answer 1

• missing sulci and gyri
• can develop at 12 weeks
• causes: genetic, trauma, toxic agents

Question 2

Polymicrogyria

Answer 2

• too many small sulci and gyri
• can be localized or general, bilateral
• causes: genetic, trauma, toxic agents

Question 3

Stages of brain development

Answer 3

• cell birth (neurogenesis, gliogenesis)
• cell migration
• cell differentiation
• cell maturation (dendrite and axon growth)
• synaptogenesis (formation of synapses)
• cell death and synaptic pruning
• myelogenesis (formation of myelin)

Question 4

Cell migration & differentiation

Answer 4

• migration: continues to about 8 months after birth, brain more sensitive to trauma during migration
• differentiation: complete at birth

Question 5

neural maturation

Answer 5

• neural pathway disruption - axon can be blocked

- incorrect pathway formation - athetosis, dystonia

Question 6

synapse formation and pruning

Answer 6

• genes, cues, and signals guide the formation of synapses
• generated independently of experience in phases (1 & 2), rapid growth (3), plateau and rapid elimination through teen years (4), plateau in middle age and steady decline with age (5)

Question 7

myelination

Answer 7

• glial cell formation begins after neuronal birth and continues through life
• myelination begins after birth and continues until 18 years old

Question 8

Kennard principle

Answer 8

-functions or placticity spared when injury occurs during infancy (easier to recover from early on)