Practice Neuro 2009 Exam Questions

Front 1

Suppose you insert an electrode into the middle of the squid giant axon. You supply depolaricing cureent and trigger an AP, and you find that the AP spreads in both directions along the axon. Under normal circumstances, what property of the Na channel prevents APs from spontaneously "reversing direction" or creating a second depolarization that spreads back towards the cell body?

Back 1

Inactivation

Front 2

Yo are recording from a neuron in voltafe clamp mode, which allows you to control the membrane potential to a different coltage V. Choose the coltage V that gives the most net current flow through the Na channels:

Back 2

0mV

Front 3

Choose the BEST answer among the options below:
a) in some cases, Na can block Ca Channels
b) In some cases, Ca can block Ca channels
c) all of the above
d) none of the above

Back 3

b)

Front 4

Cadmium blocks the flow of ions through voltage-gated Ca Channels. You are recording under typical conditions from 2 typical neurons, using an electrode in each neuron. you discover that depolarizing neuron A causes a small depolarization of neuron B; similarly, depolarizing B causes a small depolarization of neuron A. To learn more about the mechanism by which these neurons interact, which of the followint experiments might you do? Choose all that apply

a) Hyperpolarize neuron A and see whether neuron B hyperpolarizes
b) Apply tetrodotoxin(TTX) to the preparation and see if it blocks glutamatergic transmission
c) Apply cadmium to prevent chemical synaptic transmission
d) apply an inhibitor of GABAa, receptors to see if it blocks the responses

Back 4

a, c

Front 5

In normal neurons, which of the following factors in the presynaptic cell affect the size of the post synaptic cell's response?

a) The probability of vesicle filing
b) The number of releasable quanta per synapse
c) The number of synaptic contacts between the cells
d) The Probability of release

Back 5

b,c,d

Front 6

Which aspect of synaptic transmission s targeted by botulimum toxins?

Back 6

Vesicle fusion: the SNAREs

Front 7

Name the primary inhibitory neurotransmitter receptor in the brain.

Back 7

GABA(A) receptor

Front 8

Which type of ion channel is both ligand- and voltage-gated?

Back 8

NMDA receptor

Front 9

Ionotropic inhibitory transmitter receptors are most frequently

a) At the soma ad dendritic shaft
b) At the tips of the dendrites
c) At the axon terminal
d) Only on glia

Back 9

a

Front 10

Describe "temporal summation" in one sentance.

Back 10

When 2 or more impulses are received within the membrane time constant, their effect on the membrane voltage can add/summate/ride on top of one another and have a greater impact on the firing of the cell

Front 11

For each sensory modality, specify whether it is metabotropic or ionotropic
a) Vision
b) Thermosensation
c)Hearing
d) Smell

Back 11

a) Vision- M
b) Thermosensation - I
c) Hearing - I
d) Smell- M

Front 12

What are the advantages of a multi-stage amplification cascade?

a) Faster kinetics
b) More opportunities for regulation
c) Lower noise
d) More resistant to mutation

Back 12

a) Faster kinetics
b) More opportunities for regulation

Front 13

How is active rhodopsin (R*) deactivated?

Back 13

Phosporylation by GRK

Front 14

What is the primary feedback signal for adaptation in photoreceptors?

Back 14

Calcium or GCAPs reducing productio of cGMP

Front 15

In the bullfrog sympathetic nerve preparation, breif nerve stimulation leads to postsynaptic EPSPs that begin in ms but may last for minutes. These results can best be accounted for by:

Back 15

presynaptic release of AcH and the neuropeptide LHRH

Front 16

G-protein coupled receptors (GPCR) can activate effector molecules:

Back 16

a) in the presence of an RGS inhibitor
b) after B-arrestin binding
c) when bound to "homer"
d) when coupled to another GPCR

Front 17

The dopamine precursor, L-dopa is used in the tratment of Parkinson's disease. Long term consequences of L-dopa therapy include:

Back 17

b) down-regulation of postynaptic dopamine receptors
d) down-reguation of presynaptic dopamine receptors

Front 18

Metabolites of arachidonic acid are consider "uncoventional neurotransmitter" because

Back 18

They can be released postsynaptically and act presynaptically

Front 19

GPCR dimerization reuslts in:

Back 19

Changes in agonist-mediated endocytosis

Front 20

Regulators of G-protein signaling (RGS):

Back 20

activate the GTPase function og Ga proteins

Front 21

In the early 1920s, MDMA (ecstasy) was originally used in "couples therapy". This is because it primarily:

Back 21

a) promotes the release of serotonin
b) activates regions of the brain affecting mood

Front 22

What readily crosses the blood-brain barrier?

Back 22

CO2- gases

Front 23

As a result of production of CSF by choroid plexus epithelial cells, there is net absorption (from CSF to blood) of:

Back 23

K+

Front 24

Which of the following is most correct regarding he regulation of cerebral blood flow:

A. Cerebral blood flow remains constant over a range of mean arterial pressuress between 150-200mmHg
B) Cerebral blood flow increases in the setting of increased intracranial pressure.
C) Hyperventilation decreases paCO2 providing a rapid decrease in cerebral blood flow
D) Decreased cerebral blood flow is observed in the setting of hypermetabolic conditions such as seizures or hyperthermia
E) Crebrovascular resistance is primarily mediated by post capillar venules

Back 24

C.
Hyperventilation decreases paCO2 providing a rapid decrease in cerebral blood flow

Front 25

A bilateral cataract early in development is a less severe medical condition than a unilater cataract because.

Back 25

neither eye dominates in binocular competition

Front 26

How does infantile strabimus affect primary visual cortex?

Back 26

Loss of binocularly driven neurons

Front 27

What is the definition of the critical period for the development of primary visual cortex?

Back 27

The period during which visual experience shapes binocular connections in the primary visual cortex.

Front 28

Select the 2 correct statements.

A) Correction of misaligned eyes in adults rescues stereoscopic vision
B) Cortical neurons continue to be born throughout life
C) Avoid unilateral patching of eyes during early development
D) Cortical inhibitory neurons migrate along radial lial cells
E) The maintenance of ocular dominance columns depends on visual experience
F) Stimulation of the fingertips has no effect on somatosensory maps in the post central gyrus of adult monkes

Back 28

c, e

Front 29

If you rotate your head to the right in the horizontal plane, the vestibulo-ocular reflex would produce:

Back 29

a leftward slow phase eye movement

Front 30

A patient is complaining of episodic dizziness and ataxia. When trying to stand from a sitting position, the patient has a tendency to fall to the left side. A CT scan reveals a positive finding. Which of the following is most likely?

A) Damage to the left vestibular labyrinth
B) Damage to the right VIIIth nerve
C) an acoustic neuroma on the right side
D) a lesion of the left medial superior olivary nucleus

Back 30

A

Front 31

Vestibular receptor cells are directionally tuned to motion stimulations. This is accomplished by which of the following mechanisms?

A) displacement of the sterocilia toward the kinocilium produce depolarization
B) displacement of the stereocili away from the kinocilium produce hyperpolarization
C) displacement of the stereocilia orthogonal to the polarization bundle produces no response
D) All of the above

Back 31

D

Front 32

The primary circuit for the vestibulo-ocular reflex consists of a three-neuron arc. These include:

Back 32

VIIth never fibers, vestibular nuclei neurons, oculomotor neurons

Front 33

During a caloric irrigation examination, you introduce cold water into the left ear and observe what in a normal patient?

Back 33

Horizontal nystagmis with fast phases directed toward the right

Front 34

In an MRI scan, a lesion is reveled in the right lateral vestibulo-spinal tract. You would expect to find which of the following?

A) ataxic gait disorder
B) difficulty moving the head
c) nystagmus with fast phases to the left
d) downbeating nystagmus

Back 34

A

Front 35

A patient comes to you in the balance disorders clinic and is complaining of dizziness and blurred vision. You have vestibular caloric and balance tests done with the following results.
Caloric irrigation of the left ear produced normal responses.
Caloric irrigation of the right ear produced no response (abnormal).
The patient also had instability when standing on the right leg.

You order an MRI. Which scan is congruent with the test results?
a) acoustic neuroma of the right VIIIth nerve
b) a large neuroma of the cerebellar cortex
c) lesion of the left medial vestibular nucleus
d) lesion in the right abducens nucleus

Back 35

A

Front 36

Otitis media:
a) has a high incidence young children
b) can result from an anatomical blockage of the eustachian tube
c) can lead to hearing loss
d) all of the above

Back 36

D

Front 37

The malleus, incus, and stapes work together to perform which of the following?
a) amplify sound energy
b) impedance match air-to-fluid vibrations
c) transmit sound energy from the tympanic membrane to the oval window
d) all of the above

Back 37

D

Front 38

The processing of sound localization involves determing timing differences between sounds arriving at the two ears. Which auditory cells listed below are specialized for that function?
a) dorsal cochelar nucleus
b) medial superior olivary nucleus
c) dorsal tegmental nucleus
d) superior colliculus

Back 38

B

Front 39

The base of the basilar membrane encodes…
a) high intensity sounds, not low
b) low frequency sounds
c) complex sounds only, not simple frequencies
d) high frequency sounds

Back 39

D

Front 40

The auditory inner hair cells:
a) receive all of the efferent fibers from the medial superior olive
b) are innervated by 95% of the auditory afferents
c) have perilymph that bathes the stereocilia
d) are replaced by new cells every two – three days
e) all of the above

Back 40

B

Front 41

The peripheral receptors of the vestibular system lie in five separate organs for each
inner ear, including three semicircular canals and two otolith organs. The two otolith organs
are responsible for transduction of:
a) proprioceptive information from the neck
b) rotational head motion
c) linear accelerations and tilts of the head relative to gravity
d) high frequency sounds

Back 41

C

Front 42

Auditory hair cells have stereocilia that:
a) have mechanoreceptor K+ channels that are opened/closed by displacement
b) are bathed in perilymph with Na+ channels that open in response to sound
c) are stiff and push Reisner’s membrane up/down during sound stimulation
d) are anchored to the ossciles for sound transduction

Back 42

A

Front 43

Auditory aphasia (impairment of speech comprehension) often results from an
infarction of the middle cerebral artery and damage to:
a) lateral superior olivary nucleus
b) dorsal cochlear nucleus
c) medial geniculate nucleus
d) Wernicke’s area in the primary (41 & 42) accessory auditory (area 22) cortices

Back 43

D

Front 44

Sensorineural hearing loss results from:
a) a lesion in the paraflocculus
b) damage to the primary auditory cortex
c) damage to the cochlea or cochlear nerve
d) damage to Broca’s area

Back 44

D

Front 45

Questions 1-5 answers (some answers
may be used more than once; all
answers may not be used)
For questions 1-5, enter the one correct choice from the box above (1 pt each) :
a) A-alpha
b) A- beta
c) C
d) A-delta
1. “Slow” pain fibers: ____
2. The least susceptible to damage from compression: _
3. The fiber not present in cutaneous nerves: __
4. The fiber with the most myelin: ___
5. Myelinated nociceptor fibers: __

Back 45

1. C
2. C
3. A
5. D

Front 46

Neuropathic pain can arises from damage to the (choose one):
a. peripheral nerve
b. spinal cord
c. brain
d. all of the above

Back 46

D

Front 47

Within the spinal cord, nociceptor primary afferents mediate fast synaptic
transmission using which neurotransmitter?
a) GABA
b) glutamate
c) substance P
d) enkephalin
e) acetylcholine

Back 47

B

Front 48

(T/F)In the absence of specific problems on exam or MRI, a patient’s report of severe pain can be taken as a clear indication of psychological issues, and pain should not be treated.

Back 48

F

Front 49

(T/F) Descending projections from the rostroventromedial medulla to the spinal cord include endogenous pain-facilitating and pain-inhibiting projections

Back 49

T

Front 50

A patient who has lost all rods would

a. Have difficulty fixating a small target
b. Have difficulty seeing faint stars at night
c. Completely lack depth perception
d. Lose color vision
e. a and b

Back 50

B

Front 51

Where (at what stage) does the difference between on-center and off-center receptive
fields first become evident in the retina?

Back 51

The bipolar cell level

Front 52

By what mechanisms does the difference between on-center and off-center receptive fields become evident in the retina?

Back 52

By virtue of a difference in transmitter receptor (ionotropic vs metabotropic gluatmate receptor)

Front 53

___ a. First emerges in area V1
___ b. Arises because rods suppress the responses of cones
___ c. Increases sensitivity to dim illumination
___ d. Enhances the sensitivity to local spatial contrast
___ e. Occurs in bipolar cells, retinal ganglion cells, and LGN cells
___ f. d and e

Back 53

F

Front 54

You shine a light into the left eye of your patient and observe pupillary
constriction of her right eye (contralateral to the stimulus), but not of the left (ipsilateral).
Name two structures where a lesion could cause this syndrome.

Back 54

Edinger-Westphal/accesory oculomotor nucleus
Ciliary ganglion
3rd nerve

Front 55

A lesion that destroys the magnocellular LGN layers, leaving the parvocellular layers intact, should result in
____ a. Color blindness
____ b. Decreased sensitivity to rapid motion
____ c. Decreased sensitivity to fine details
____ d. Decreased sensitivity to slowly moving patterns
____ e. a and c

Back 55

B

Front 56

Cells selective for binocular disparity
_____a. should be absent or rare in strabismic patients
_____b. occur outside layer 4C of area V1
_____c. first appear in the magnocellular layers of the LGN
_____d. are found exclusively in layer 4C of area V1
_____e. a and b

Back 56

E

Front 57

Ocular dominance stripes in V1:
_____ a. are the first site of binocular integration in the visual system
_____ b. represent a fixed angle in visual space, so are much wider for the fovea than the periphery
_____ c. involve side-by-side segregation of inputs from the left eye and right eye
_____ d. are most pronounced in layer 4C
_____ e. c and d

Back 57

E

Front 58

In area V1 of macaque monkeys, one cubic millimeter of cortex contains:
_____a. about 1,000 neurons, all belonging to the same ocular dominance stripe and the
same orientation column
_____b. about 10,000 neurons, each responding best to a different color
_____c. about 100,000 neurons, collectively representing both eyes and all possible
orientations
_____d. about 1,000,000 neurons, each receiving direct inputs from many LGN neurons
_____e. about 10,000,000 neurons, each selective for a different direction of motion

Back 58

C

Front 59

Area MT in primates
____a. mediates color perception
____b. projects mainly to inferotemporal cortex
____c. contributes to motion perception
____d. is one of the ‘dorsal stream’ visual areas
____e. c and d

Back 59

E

Front 60

You have examined a series of patients having partial loss of vision.
For each visual field deficit indicated below on the perimetry chart (where shading indicates a deficit and
white indicates normal vision), state a specific structure or region, including which side of the brain, that
could account for the problem.

Back 60

1. right optic tract or optic radiation or occipital
lobe/striate cortex

2. (occipital) cortex or right ventral striate optic
radiation, Meyer's loop

3. Left optic nerve (or retina)

4. optic chiasm

Front 61

All but one pair of the anatomical structures originate from the same embryonic
‘vesicle’. Which pair does not?:
a. Caudate nucleus; visual cortex
b. Retina; hypothalamus
c. Substantia nigra; hippocampus
d. Superior colliculus; inferior colliculus
e. Pons; cerebellum

Back 61

C

Front 62

The cephalic flexure brings what structures closer together:
a. cerebrum and cerebellum
b. pons and medulla
c. forebrain and abdomen
d. midbrain and cerebellum

Back 62

C

Front 63

Spemann’s Organizer “induces” neural tissue by:
a. Releasing BMP4 to activate TGFb receptors
b. Antagonizing TGFb receptors
c. Inhibiting BMP4 release from surrounding tissues
d. Transforming directly into neural tissues

Back 63

B

Front 64

Name one developmental gene described during lecture that when mutated in humans
has an effect on neural development:

Back 64

Sonic Hedgehog (SHH)
Wnt1
Reelin
Reelin receptor
Doublecortin/Lis1
Robo3

Front 65

Briefly describe the effect of the mutation of the developmental gene described during lecture that when mutated in humans
has an effect on neural development:

Back 65

Any of the following:
Sonic Hedgehog (SHH) - Holoprosencephaly
Wnt1 - absence of midbrain and cerebellum
Reelin - Lissencephaly (Norman-Roberts syndrome)
Reelin receptor - cerebellar hypoplasia and ataxia (VLDLR-associated cerebellar
hypoplasia)
Doublecortin/Lis1 – Double cortex, Lissencephaly
Robo3 - Horizontal Gaze Palsy (with Progressive Scoliosis)

Front 66

What is the relationship between neuronal birth order and cortical layering?

Back 66

Inside out . Lower layers are born earlier than upper layers

Front 67

For each of the following properties, specify how it depends on membrane surface
area A: whether it increases with A (i.e., is proportional to A), decreases with A (i.e., is
proportional to 1/A), or is independent of membrane surface area:
a) Membrane resistance ____________________
b) Membrane capacitance ____________________
c) Membrane time constant ___________________

Back 67

A) Decreases
B) Increases
C) Independent

Front 68

There are two main ways to change an axon so that passive electrical signals
propagate farther and more quickly. What are they?

Back 68

Increase diameter of axon
Myelination

Front 69

Choose all that apply: the action potential
a) makes signaling instantaneous
b) amplifies the magnitude of the voltage change
c) prevents the region of depolarization from becoming wider over time
d) is necessary for long-distance signaling

Back 69

B,C

Front 70

Name one type of glial cell

Back 70

Astrocyte, oligodendrocyte, Schwann cell, microglia

Front 71

What is the major effect of each K channel on a neuron
A) Kir
B) Kv
C)KCa

Back 71

A) setting resting potential
B) repolarizing the membrane at the end of an AP
C) Inhibiting a neuron after a period of high activity

Front 72

See Picture for Question

Back 72

See Picture