chapter twenty three

Question 1

cell layers lining central vesicle

Answer 1

ventricular zone

Question 2

cell layer on the outside (by pia mater)

Answer 2

marginal zone

Question 3

neural stem cells in the ventricular zone divide to give rise to neuron and glia, mutipotent

Answer 3

radial glial cells

Question 4

can turn into any kind of brain cell

Answer 4

multipotent

Question 5

symmetrical division in cell proliferation gives rise to ____ cells that ____ in sub-ventricular zone

Answer 5

daughter; stay

Question 6

asymmetrical division in cell proliferation gives rise to ____ cells that ____ in sub-ventricular zone, _____ further divide

Answer 6

daughter; migrates; cannot

Question 7

pyramidal cells and astrocytes migrate ______ from ventricular zone of dorsal telencephalon (along thin radial glial fibers)

Answer 7

vertically

Question 8

inhibitory GABAergic interneurons and oligo. migrate _____ from ventral telencephalon

Answer 8

laterally

Question 9

cells take the appearance and charac. of a neuron ____ reaching its destination based on chemical environment

Answer 9

after

Question 10

growing end of a neurite

Answer 10

growth cone

Question 11

flat waving sheets at tip of growth cone

Answer 11

lamellipodia

Question 12

_______ _____ protein gives developing pyramidal neurons the characteristic shape

Answer 12

semaphorin 3A

Question 13

cortical ______ in the ventricular zone replicated by radial glial guides

Answer 13

“protomap”

Question 14

set of genetic instructions orchestrated from within ____ ____ dictates cortical organization

Answer 14

ventricular zone

Question 15

mature cortical sheet is a “____ ____” of interconnecting neurons

Answer 15

patchwork quilt

Question 16

some neural precursor cells “stray”- expression of certain______ ______ dictates destination

Answer 16

transcription factors

Question 17

_____ _ expression associated with rostral cortical destination

Answer 17

Pax6

Question 18

_____ _ expression associated with caudal cortical destination

Answer 18

Emx2

Question 19

three phases of axon guidance

Answer 19

1. pathway selection, 2. target selection, 3. address selection

Question 20

(growing axon: pathway)- axon travels along _______ ______ which has substrates filopodia can grab

Answer 20

extracellular matrix (ECM)

Question 21

substrate on ECM

Answer 21

laminin molecules

Question 22

on filopodia, can bind to laminin to elongate axon

Answer 22

integrin molecules

Question 23

“stretch” as nervous system expands

Answer 23

pioneer axons

Question 24

axons traveling together stick together

Answer 24

fasciculation

Question 25

signals that attract or repel a growth cone based on each growth cone's surface molecules

Answer 25

guidance cues

Question 26

chemical signal acting over a distance to draw growth cones toward it

Answer 26

chemoattractant

Question 27

diffiusable molecule that drives axon growth cones away

Answer 27

chemorepellant

Question 28

chemoattractant for axon to grow towards midline

Answer 28

netrin

Question 29

chemorepellant for axon to move away from midline after it decussates

Answer 29

slit

Question 30

the fate of a neural stem cell is determined while it is in the ____ ____

Answer 30

subventrical zone

Question 31

chemical markers on growing on axons are matched with complementary chemical markers on their targets

Answer 31

chemoaffinity hypothesis

Question 32

two processes for refining brain connections after axons have found their targets

Answer 32

cell death; synaptic pruning

Question 33

neurons compete for trophic factors, neurons with insufficient trophic factor exposure will die by _____

Answer 33

apoptosis; cell death

Question 34

Synaptic capacity peaks in development and declines as neurons mature * Many causes for pruning: hormones, experience, stress * Synaptic connections not part of a functional network are pruned away in an experience-dependent manner

Answer 34

synaptic pruning

Question 35

Developmental period during which such rearrangement is possible; Developmental “window” during which some event has a long-lasting influence on the brain

Answer 35

critical period

Question 36

change from one pattern of innervation to another

Answer 36

Activity-dependent synaptic rearrangement

Question 37

prenatal: specific chemical signals sent out by different cells to organize neural connections

Answer 37

chemoaffinity

Question 38

postnatal: Connections become more precise with the passage of time due to correlated activity of their inputs

Answer 38

experience

Question 39

“When the axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased.

Answer 39

hebb synapse

Question 40

“Cells that fire together wire together” * Winner-takes-all

Answer 40

hebbian modification

Question 41

input from each eye kept separate

Answer 41

ocular dominance columns

Question 42

Postnatal or prenatal: Fine-tuning of connections proceeds in an activity- dependent manner

Answer 42

postnatal

Question 43

_____ _____ leads to ocular dominance shift

Answer 43

synaptic competition

Question 44

Rapid changes in ocular domincance ______ be due to gross changes in axonal arborization

Answer 44

cannot

Question 45

the rapid changes in ocular dominance must be changes in ______ -_____ of the synapse

Answer 45

molecular composition

Question 46

A condition in which vision in one eye is reduced as a result of disuse; usually caused by a failure of the two eyes to point in the same direction

Answer 46

amblyopia

Question 47

Related condition where the two eyes are not perfectly aligned (“cross-eyed”)

Answer 47

strabismus

Question 48

Monocular deprivation depends on what two neurotransmitter systems

Answer 48

NE and Ach

Question 49

what are the two basic rules for synaptic modification

Answer 49

Neurons that fire together wire together Neurons that fire out of sync lose their link

Question 50

traditional glutamate-gated receptors that conduct sodium only

Answer 50

AMPARs

Question 51

glutamate-gated receptors that conduct sodium and calcium, but only when the magnesium block is removed

Answer 51

NMDARs

Question 52

metabotropic glutamate receptors also play a role

Answer 52

mGluRs

Question 53

NMDARs have two unique properties

Answer 53

they are voltage-gated (needs to be alot of action to remove Mg to sufficiently depolarize ) they conduct Ca

Question 54

Pre- and postsynaptic neurons fire ___ _____

Answer 54

in sync

Question 55

Strength of synaptic transmission increased by ______ NMDAR activation

Answer 55

strong

Question 56

In response to stimulation at a synapse, changed amplitude of an excitatory postsynaptic potential that lasts for hours to days or longer is what? (plays part in associative learning)

Answer 56

long-term potentiation

Question 57

when Pre- and postsynaptic neurons fire out of sync it is called

Answer 57

long term depression

Question 58

Plasticity diminishes for 3 reasons

Answer 58

- When axon growth ceases - When synaptic transmission matures (properties of LTP and LTD vary with age) - When cortical activation is constrained (NE and ACh less effective)