NEUR533 - Wiring the Brain

Question 1

Learning outcomes

Question 2

Review lateral geniculate nucleus and ocular integration - 12 layers from neurobiology and neuroanatomy

Question 3

Wiring of the brain neuroanatomy and neurobiology - KNOW AND REMEMBER

Question 4

NEUROGENESIS - radial glial cells

Question 5

What cells give rise to neurons in astrocytes (neurogenesis cell proliferation) in the cerebral cortex?

Answer 5

Radial glial cells

Question 6

What are the 2 proteins for transcription factors and cleavage plane during cell division to determine fate of daughter cells, in radial glial cells?

Answer 6

Notch-1 & numb

Question 7

REVIEW CELL MIGRATION PROCESSES

Question 8

What direction do pyramidal cells and astrocytes migrate from the ventricular zone?

Answer 8

Vertically

Question 9

What type of fibres do pyramidal cells and astrocytes utilise to migrate from the ventricular zone?

Answer 9

Thin radial glial fibers

Question 10

What direction do inhibitory interneurons (e.g. GABAergic neurons)and oligodendroglia move for cell migration?

Answer 10

Laterally/horizontal

Question 11

What is the first layer cells migrate to take up residence?

Answer 11

Subplate layer - eventually disappears

Question 12

Where do the next cells go to divide migrate to? (2nd stage)

Answer 12

The cortical plate

Question 13

The first cells to migrate and arrive at the matrix become what layer?

Answer 13

Layer VI (bottom layer)

Followed by V, IV, III and so on e.g. “inside out”

Question 14

Review cell differentiation process

Answer 14

Differentiation of cortical areas

Question 15

What are the 3 phases of pathway formation?

Answer 15

Pathway selection
Target selection
Address selection

Question 16

What information is processed in he medial geniculate nucleus?

Answer 16

Auditory signals

Question 17

What info is processed in the lateral geniculate nucleus?

Answer 17

Visual stimuli

Question 18

What is a growth cone?

Answer 18

The growing tip of a neurite

Question 19

What are the 2 ‘feelers’ of neuronal tip growth and pathway formation?

Answer 19

Lamillipodia
Filopodia

Question 20

What are the 2 core molecules that are interacting within the Folopodia extracellular matrix? (neurites)

Answer 20

Laminin and integrin molecules

Question 21

Axon guidance
Tehy are all about chemo communication

Question 22

Axon Guidance
Growth guidance cuies

Question 23

What is the growth guidance cue chemoattractant?

Answer 23

Netrin

Question 24

What is the growth guidance cue chemorepellant?

Answer 24

Slit
Robo is the receptor

Question 25

What are the factors guiding retinal axons to tectum?

Answer 25

Ephrins/eph (repulsive signal)

Question 26

Who came up with the chemoaffinity hypothesis in the 1940s?

Answer 26

Sperry

Question 27

Retinotectal projection in frogs

Answer 27

Excellent research in the role of retinotopic mapping

Question 28

Neuromuscular synapse

Question 29

MUST LEARN THE FORMATION OF CNS SYNAPSES

Question 30

What is the first step of CNS formation of synapses?

Answer 30

Dendritic filopodium contact axon

Question 31

What is the 2nd step of CNS formation of synapses?

Answer 31

Synaptic vesicles and active zone proteins recruited to presynaptic membrane

Question 32

What is the 3rd step of CNS formation of synapses?

Answer 32

Receptors accumulate on postsynaptic membrane

Question 33

LEARN THE ELIMINATION OF CELLS AND SYNAPSES

Answer 33

Sunapse elimination in the neuromuscular junction

Question 34

Activity-dependent synaptic rearrangement

Answer 34

Segregation of retinal inputs to teh LGN - fine tuning - based on retinal waves -

Question 35

Striate cortex - uses radio tracers to find ocular dominance columns

Question 36

What did monocular deprivation experiments show us?

Answer 36

- Ocular dominance shift - Plasticity of binocular connections - Synaptic competition

Question 37

Ocular dominance shift - #3 is max convergence - Binocular vision youtube to understand

Answer 37

Question 38

Strabismus - lazy eye

Answer 38

odulatory influences on cortical circuits

Question 39

What are 3 key factors for modulatory influences on cortical circuits:

Answer 39

_ retinal activity before birth - visual environment after birth - enabling factors e.g. Ach - glutamate

Question 40

Synaptic plasticity

Question 41

What are the 2 glutamate receptors for excitatory synaptic transmission?

Answer 41

AMPA receptors (ion gated) NMDA (unique properties)

Question 42

What are the 2 unique properties of NMDA receptors?

Answer 42

Voltage gated ion channel owing to to action of Mg2+ (ligand and voltage gated e.g. double gated) - Conducts Ca2+ - High and low Ca2+ levels are key

Question 43

Long term potentiation with NMDA receptors

Question 44

Strong NMDA receptor activation =

Answer 44

Strengthening of synaptic transmission (LTP)

Question 45

_____ entry throgh the NMDA receptor channel triggers the biochemical mechanisms that modify ____ effectiveness

Answer 45

Ca2+ Synaptic

Question 46

What is the long-term depression associated with:?

Answer 46

- Neurons firing out of sync 'lose their link' - Loss of AMPA receptors - Synaptic pruning - Key in teenage years

Question 47

Deprivation leads to reduced visual responsiveness.

Question 48

What are 3 hypotheses why plasticity diminishes after critical periods (e.g. teens, young adults aged 21)

Answer 48

- When axon growth ceases - Synaptic transmission matures - Cortical activation is constrained

Question 49

Is intrinsic inhibitory circuitry late to mature?

Answer 49

Yes

Question 50

What does understanding the development regulation of plasticity help recovery from what?

Answer 50

CNS damage

Question 51

Summary