Deck 9: Development of the Nervous System

Question 1

A zygote divides to form

A) a sperm cell and an ovum.
B) two ova.
C) two zygotes.
D) two daughter cells.
E) two sperm cells.

Answer 1

two daughter cells.

Question 2

Most neural proliferation in the developing neural tube occurs in the layer that adjacent to

A) the fluid-filled central canal.
B) the cortex.
C) the marginal zone.
D) layer 6.
E) the neural crest.

Answer 2

the fluid-filled central canal.

Question 3

The neural plate is a patch of

A) multipolar neurons.
B) ectodermal tissue.
C) mesoderm.
D) endodermal tissue.
E) growth cones.

Answer 3

ectodermal tissue.

Question 4

Many new neural tube cells migrate radially

A) along axons of other neurons.
B) along radial glial cells.
C) to the ventricular zone.
D) all of the above
E) both B and C

Question 5

By 40 days after conception, swellings are clearly visible at the anterior end of the neural tube. There are

A) 2.
B) 3.
C) 4.
D) 32.
E) 64.

Question 6

The very first cells to develop in the embryo are

A) multipolar.
B) bipolar.
C) myelinated.
D) totipotent.
E) mesodermal.

Question 7

A developing cell that is totipotential

A) is capable of developing into any type of cell in the organism.
B) is totally committed to one cell type for life.
C) cannot divide.
D) is totally developed and will not differentiate.
E) is entirely potent in excitation or inhibition.

Question 8

The process of the growth of a fertilized egg into a mature nervous system is called

A) neural growth.
B) neuroplasticity.
C) neurodevelopment.
D) psychological development.
E) rewiring.

Question 9

Immature cells that have the potential to develop into many, but not all, classes of mature cells (e.g., blood, skin, hair, neurons) are called

A) ependymal.
B) pluripotent.
C) ventricular.
D) multipolar.
E) totipotent.

Question 10

Most cell division in the developing neural tube occurs in the

A) hindbrain zone.
B) ventricular zone.
C) ventricles.
D) posterior zone.
E) midbrain.

Question 11

The first major phase of neurodevelopment is induction of the

A) neural tube.
B) neural grove.
C) growth cones.
D) neural plate.
E) neural growth factors.

Question 12

The neural groove develops into the neural

A) tube.
B) plate.
C) mesoderm.
D) endoderm.
E) cord.

Question 13

The neural plate develops directly into the

A) neural tube.
B) neural groove.
C) brain.
D) CNS.
E) PNS.

Question 14

Embryonic cells that have the potential for unlimited renewal and have the ability to develop into different kinds of mature cells if they are transplanted to different sites are often called

A) daughter cells.
B) embryonic stem cells.
C) zygotes.
D) multipolar cells.
E) ectodermal cells.

Question 15

Developing cells that have the potential to develop into neurons of any type but into no other class of body cells are said to be

A) multipotent.
B) totipotent.
C) multipolar.
D) pluripotent.
E) unipolar.

Question 16

By 40 days after conception, three swellings become visible at the anterior end of the human neural tube. The most anterior of these swellings eventually develops into the

A) brain.
B) midbrain.
C) hindbrain.
D) forebrain.
E) ventricles.

Question 17

The case of Genie emphasizes the role of

A) the brain in behavior.
B) experience in human neural and psychological development.
C) the brain in language.
D) language in learning.
E) neuroplasticity in development.

Question 18

After the formation of the neural tube, the number of cells destined to become part of the adult nervous system

A) actually declines.
B) stays the same until the end of the neural-plate phase.
C) stays the same until the end of the neural-groove phase.
D) increases rapidly.
E) quickly doubles and then declines.

Question 19

At 18 days after conception, this structure becomes visible in the developing embryo; it is the neural

A) mesoderm.
B) tube.
C) plate.
D) floor.
E) crest.

Question 20

Many cells of the neural tube have lost their pluripotency and have become

A) totally specified.
B) totipotent.
C) multipotent.
D) mesodermal.
E) neural plates.

Question 21

In Sperry's classic studies of eye rotation and regeneration of the optic nerves, he assessed the visual capacities of his subjects by assessing their ability to

A) strike accurately at fly-like stimuli.
B) identify colors.
C) perform a visual discrimination task.
D) detect the presence of dim lights.
E) solve maze problems.

Question 22

Research on the migration of developing neocortical neurons has made one important point: __________ is everything.

A) Timing
B) Location
C) Genetics
D) Experience
E) Age

Question 23

Sperry's initial version of the chemoaffinity hypothesis of axon growth has difficulty accounting for

A) the results of Sperry's own eye-rotation regeneration experiments.
B) the ability of axons to grow to their correct targets.
C) the ability of axons to follow exactly the same circuitous route to their target in every member of a species.
D) all of the above
E) both A and B

Question 24

Frogs, unlike mammals, have retinal ganglion cells that are capable of

A) degeneration.
B) proliferation.
C) color vision.
D) regeneration.
E) aggregation.

Question 25

In addition to the radial migration of developing neurons, there is considerable __________ migration.

A) rapid
B) tangential
C) intermediate
D) circuitous
E) axonal

Question 26

Which of the following are amoebalike in their appearance and movements?

A) growth cones
B) ependymal cells
C) neural cell-adhesion molecules
D) radial glial cells
E) retinal ganglion cells

Question 27

The pattern of neural migration that is indicated by the arrows in this illustration is

A) radial.
B) tangential.
C) inside out.
D) outside in.
E) posterior.

Question 28

Sperry's experiments on eye-rotation in frogs led to an influential hypothesis that explains how growth cones find their way to their targets: the

A) radial glial hypothesis.
B) cell-adhesion hypothesis.
C) chemoaffinity hypothesis.
D) growth cone hypothesis
E) CAM hypothesis

Question 29

At the tip of each growing axon or dendrite is an amoebalike process called

A) an amoeba cell.
B) a growth cone.
C) a pioneer cell.
D) a blueprint cell.
E) a growth cell.

Question 30

The pattern of migration of future neocortical neurons is referred to as

A) accelerated.
B) insidious.
C) inside out.
D) subventricular.
E) ependymal.

Question 31

Cell adhesion molecules are thought to mediate

A) differentiation.
B) aggregation.
C) proliferation.
D) sprouting.
E) cell death.

Question 32

The neural crest

A) is just anterior to the neural tube.
B) is the bottom of the neural tube.
C) develops into the hindbrain.
D) develops into the PNS.
E) develops into the spinal cord.

Question 33

At 24 days after conception, the precursor of the PNS is visible in the developing embryo. This structure, which is illustrated here at the end of the pointer line, is the neural

A) tube.
B) plate.
C) crest.
D) groove.
E) stem.

Question 34

Only those growth cones that are not pioneer growth cones can normally find their way to their targets by

A) chemoaffinity.
B) fasciculation.
C) blueprints.
D) topographic gradients.
E) stopping and asking for directions.

Question 35

The first growth cone of a developing tract to reach the target is called a __________ growth cone.

A) fast
B) pioneer
C) quick
D) early
E) premier

Question 36

In frogs, salamanders, and other simple vertebrates, retinal ganglion cells project primarily to the

A) thalamus.
B) tectum.
C) tegmentum.
D) cerebellum.
E) visual cortex.

Question 37

The neural crest develops into the

A) ventricular system.
B) cortex.
C) peripheral nervous system.
D) circulatory system of the brain.
E) neural tube.

Question 38

There seem to be two different mechanisms of neural migration: glia-mediated migration and

A) amoeboid migration.
B) somal translocation.
C) pioneer migration.
D) growth cone translocation.
E) neural cresting.

Question 39

During the formation of the neural tube, a few cells break off from the neural tube and form a structure that lies just dorsal to the tube. This structure is the neural

A) groove.
B) canal.
C) crest.
D) zone.
E) layer.

Question 40

Growth cones extend and retract finger-like cytoplasmic extensions as if they were feeling their way. These extensions are called

A) adhesion digits.
B) growth cone adhesion digits.
C) filopodia.
D) pseudopodia.
E) siphons.

Question 41

When it comes to synaptogenesis, neurons display a substantial degree of

A) specificity.
B) promiscuity.
C) monogamy.
D) faithfulness.
E) inertia.

Question 42

The postnatal growth of the human brain results from

A) synaptogenesis.
B) an increase in the number of neurons.
C) myelination.
D) all of the above
E) both A and C

Question 43

Synaptic density in the primary visual cortex of infants

A) is maximal by the seventh or eighth postnatal month, and then it declines.
B) almost reaches adult levels by the seventh or eighth prenatal month.
C) follows the same course of development as the myelination of prefrontal cortex.
D) both A and C
E) both B and C

Question 44

Evidence suggests that many neurons die during development because

A) they are genetically programmed to die.
B) of their inability to compete successfully for their target's life-preserving chemicals.
C) of failures of regeneration.
D) both A and B
E) both B and C

Question 45

In support of the topographic-gradient hypothesis, it has been shown that

A) axons do not grow out from the retinas until the retinas are fully grown, which is why babies have disproportionately large eyes.
B) axons do not grow out from the retinas until their target structures (e.g., optic tectums) are fully grown.
C) retinas and optic tectums always grow in precise proportion to one another.
D) the synaptic connections originally formed by retinal ganglion cells on the optic tectums gradually shift as both the eyes and optic tectums grow at different rates during development.
E) both A and B

Question 46

The development of the human brain is unique in that

A) there is no early cell death.
B) there is no early reorganization.
C) it develops so slowly.
D) it develops so quickly.
E) the PNS develops before the CNS.

Question 47

Most of the cell death associated with early development of the brain is

A) necrotic.
B) passive.
C) apoptotic.
D) both A and B
E) both B and C

Question 48

If an optic nerve of a mature frog is transected and half of the associated retina is destroyed,

A) the axons grow out from the retinal ganglion cells in the remaining half of the retina to their original targets on the optic tectum.
B) the destroyed retina regenerates and then axons grow out from the complete retina and innervate the optic tectum in the species-typical fashion.
C) the axons grow out from the retinal ganglion cells in the remaining half of the retina to targets systematically distributed over the entire optic tectum.
D) half of the optic tectum degenerates.
E) both A and D

Question 49

Between birth and adulthood, the size of the human brain

A) doubles.
B) quadruples.
C) actually declines.
D) stays about the same although the skull grows.
E) increases 10 fold.

Question 50

A recent finding is that synaptogenesis seems to depend on the presence of

A) astrocytes.
B) neurons.
C) growth cones.
D) pioneer cones.
E) guidance molecules.

Question 51

In vitro, neurons will form synapses

A) only with their correct targets.
B) only with neurons of the same type.
C) with almost any neuron.
D) only with glial cells.
E) only with the correct glial cells.

Question 52

Apoptosis is safer than necrosis because apoptosis does not involve

A) neuron death.
B) inflammation.
C) suicide.
D) degeneration.
E) synapse rearrangement.

Question 53

Neuron death

A) starts to occur in humans around the age of 50.
B) is a stage of normal early neural development.
C) is rare in healthy humans until after puberty.
D) is a common, but unfortunate, consequence of accidental exposure to neural gradients.
E) is always followed by regeneration.

Question 54

Eyes and optic tectums grow at different rates. As they grow, the synaptic connections that were originally formed on the tectum by axons of retinal ganglion cells shift so that the retina is always fully and faithfully mapped on the tectum. This finding supports the

A) chemoaffinity hypothesis.
B) pioneer hypothesis.
C) topographic-gradient hypothesis.
D) all of the above
E) both A and C

Question 55

Neurotrophins can

A) promote neuron growth.
B) promote neuron survival.
C) function as axon guidance molecules.
D) all of the above
E) both A and B

Question 56

Neurotrophins

A) are life-preserving chemicals for neurons.
B) are supplied to neurons by their synaptic targets.
C) promote neuron death.
D) both A and B
E) both B and C

Question 57

Less is known about synapse formation than axon growth because synapse formation requires

A) fasciculation.
B) coordinated activity in at least two cells.
C) growth cones.
D) guidance molecules.
E) regeneration.

Question 58

The human brain grows after birth because of

A) synaptogenesis.
B) myelination.
C) increased dendritic branching.
D) all of the above
E) none of the above

Question 59

The last part of the human brain to reach full maturity is the

A) hippocampus.
B) prefrontal cortex.
C) amygdala.
D) occipital cortex.
E) hypothalamus.

Question 60

The general effect of synapse rearrangement is to

A) increase the number of different target cells innervated by each neuron.
B) increase the number of synaptic contacts received by each neuron.
C) focus the output of each neuron on fewer postsynaptic cells.
D) increase the ratio of axosomatic synapses to axodendritic synapses.
E) increase the number of synapses.

Question 61

In one study, a few days of early monocular deprivation decreased the axonal __________ of lateral geniculate nucleus neurons that normally conducted signals from the deprived eye.

A) branching
B) regeneration
C) width
D) layers
E) degeneration

Question 62

Studies have shown that about __________ new neurons are created each hour in the hippocampus of adult animals?

A) 4
B) 8
C) 50
D) 100
E) 2,000

Question 63

The prefrontal cortex seems to play a role in

A) working memory.
B) planning and carrying out sequences of action.
C) inhibiting responses that are inappropriate in the current situation but not in others.
D) all of the above
E) both A and B

Question 64

It is now generally acknowledged that adult brains are

A) incapable of substantial reorganization.
B) capable of major changes.
C) not as plastic as developing brains.
D) both B and C
E) none of the above

Question 65

If just one eye is deprived of input for a few days early in life,

A) the contralateral visual cortex totally degenerates.
B) there is a decrease in the ability of visual cortex to be activated by stimulation of the deprived eye.
C) there is an increase in the ability of visual cortex to be activated by stimulation of the nondeprived eye.
D) both A and B
E) both B and C

Question 66

The disruptive effects of total visual deprivation of the left eye on subsequent vision through the left eye are greater when the

A) right eye is deprived at the same time.
B) deprivation occurs early in life.
C) right eye is not deprived at the same time.
D) both A and B
E) both B and C

Question 67

In comparison to the cortices of rats that had been reared in enriched environments, the cortices of rats that had been reared by themselves in barren cages

A) were thinner.
B) had less dendritic development.
C) had fewer synapses per neuron.
D) all of the above
E) none of the above

Question 68

Early monocular deprivation

A) eliminates ocular dominance columns.
B) decreases the width of ocular dominance columns from the deprived eye.
C) increases the width of ocular dominance columns from the nondeprived eye.
D) causes ocular dominance columns to develop sooner.
E) both B and C

Question 69

The course of human cognitive development is thought to reflect development in the

A) prefrontal cortex.
B) hippocampus.
C) secondary neocortex.
D) posterior parietal cortex.
E) hypothalamus.

Question 70

Several studies have shown that early music training increases the size of the

A) auditory cortex that responds to complex musical tones.
B) right hemisphere.
C) auditory cortex that responds to pure tones.
D) brain.
E) auditory cortex.

Question 71

The first evidence that new neurons can be created in the brains of adult vertebrates came in the 1980s from the study of

A) the hippocampus.
B) the olfactory bulbs.
C) songbirds.
D) hamsters.
E) the amygdala.

Question 72

It has been suggested that human infants between 7 and 12 months old make perseverative errors because they do not have a fully developed

A) cortex.
B) prefrontal cortex.
C) hippocampus.
D) visual system.
E) motor system.

Question 73

Experiences that permit information in brain genetic programs to be expressed and maintained are called

A) instructive experiences.
B) permissive experiences.
C) critical experiences.
D) sensitive experiences.
E) none of the above

Question 74

How long does one eye have to be deprived of stimulation early in life in order to reduce its ability to activate visual cortex?

A) a few days
B) a few minutes
C) a few seconds
D) a few years
E) a few months

Question 75

In a classic experiment, Knudsen and Brainard (1991) raised barn owls with vision-displacing prisms over their eyes. This led to the ontogenetic development of

A) a corresponding shift in the auditory topographic map in the tectum.
B) a discrepancy between where a stimulus was heard to be and where it was seen to be.
C) the degeneration of the tectum.
D) the degeneration of the visual tectum.
E) the degeneration of the auditory cortex.

Question 76

Perseveration is the tendency to

A) form long-term working memories.
B) form permanent short-term memories.
C) continue making formerly correct responses that are currently incorrect.
D) continue making formerly incorrect responses that are currently correct.
E) fasciculate.

Question 77

Perseverative errors are often made by children between the ages of

A) 3 to 5 months.
B) 7 to 12 months.
C) 1 to 2 years.
D) 2 to 4 years.
E) 4 to 8 years.

Question 78

In mammals, adult neurogenesis occurs in the

A) hippocampus.
B) olfactory bulb.
C) amygdala.
D) all of the above
E) both A and B

Question 79

Functions of the prefrontal cortex include

A) working memory.
B) planning and carrying out sequences of action.
C) locating objects in space.
D) all of the above
E) both A and B

Question 80

In a classic experiment, Roe and colleagues (1990) caused the developing axons of ferret retinal ganglion cells of the visual system to synapse in the medial geniculate nuclei of the auditory system. Once the ferrets matured, their

A) auditory cortex responded to visual stimuli.
B) auditory cortex was laid out retinotopically.
C) auditory cortex had totally degenerated.
D) both A and B
E) both A and C