Week 8- Neurodev

Question 1

neuron number in the adult vs the neocortex

Answer 1

81.6billion vs 16.3 billion

Question 2

when does development of the brain start

Answer 2

at the srat of the 3rd week of gestation

Question 3

Neural tube formation

Answer 3

the notochord starts forming from the mesoderm at week 3 gestation

this induces the formation of the neural plate from the ectoderm which then fold to form the nerual tube

by week 4 the neural tube has separated from the ectoderm

Question 4

the nerual tube is the precursor of

Answer 4

the brain and spinal chord

Question 5

How many distinct layers are there in the neocortex

Answer 5

5-6

Question 6

How are the excitatory projection neruons and modulatory/regulatory neurons located in the neocortex

Answer 6

the excitaotry are lcoated deeper but the modualtory are more superficial

Question 7

Process of neuronal proliferation, differentiation and migration

Answer 7

Question 8

The 2 migration patterns seen are

Answer 8

1. Radial migration.progenitor cells which devlop into excitaotry projection neurons. these neurons orginicate from the VZ and undergo cell division and migrate to the dorsal surface of the brain by climbing along process extending from radial cells(radial migration)
2. Tangential migration. progenitors–>modulatory inhibitory neurons. originate form the ganglionic eminence and they migrate tangentially

Question 9

Structural changes seen in the adolescent brain

Answer 9

reduction in grey matter of neocortex because pf synaptic pruning

increase in white matter because of increased myleination and connecitvey

axonal sprouting and growth in circuits in the amygdala and cortex

Question 10

Behavioural changes seen in the adolescent brian

Answer 10

increased social behaviour because of axonal sprouting/growth in circuits in the amygdala and cortex

novelty and sensation seeking

tendencies towards risk-taking

emotional instbaility

impulsivity

dominance of peer relationships

Question 11

Opening and shutting of higher cognitive function. Whar are they and when di they open and shut?

Answer 11

1. Senses
   
   • opens soon after infancy and closes in childhood
2. Language
   
   • opens in infancy and persists into childhood and never closes fully
3. Higher cognition
   
   • opens in childhood and continues

the opening and shutting of different critical periods allows for a childs acquisition of increasingly complex skills

Question 12

Are neurodevelopmental disorders psychiatric illnesses?

Answer 12

yes they are and they develop because of abnormal neurodevelopment

Question 13

what causes NDD?

Answer 13

Defecits in neurogeneis, progneitor cell proliferation, migration, synapse formation and mylination during embryogeneis

Question 14

symptoms of NDD

Answer 14

Disabilities in cognitive, social, motor and affective function

Question 15

When are NDDs usually picked up

Answer 15

usually at birth or during infancy

sometimes during adolescence

Question 16

are NDDs purely genetically caused?

Answer 16

not its both environmental and genetic

but NDDs are highly heritable and genrlally polygenic

Question 17

examples of monogenic NDDs

Answer 17

Angelmans and Fragile X

Question 18

tonic GABA release…

Answer 18

stimulates and guides migration of projection neurons

Question 19

How is GABA invovled in maturation of neuronal circuits

Answer 19

GABA excites/depolarises post synaptic targets because of high intracellular release of Cl. this current is crucial to generating synchronised patterns of activity of developing networks, processes important for maturation

Question 20

The GABA excitatory/inhibitory switch?

Answer 20

the switch from excitatory to inhibitory occurs at childbirth and is thought to protect neurons from hypoxia and ischemic damage during complicated of difficult deliveries

Question 21

Desychronised spontanoeus networks coincide with..

Answer 21

increase influence of sensory experience where external signals compete with internally generated activity to shape synaptic connectivity.

Question 22

Excitatory and inhibitory imbalance theory for NDDs

Answer 22