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BIOL 415 Nerve cell mechanisms in behavior
Test 2 Thursday May 11, 2017 ­p; Prof. Stark
All questions are short answer. 65 points total
1. For cAMP in olfactory receptor cells, answer either (1) What enzyme makes
it? Or (2) What does it do?
adenylate cyclase, gates a sodium-calcium channel
2. Olfactory bulb targets (pyriform cortex, olfactory tubercle, amygdala
and entorhinal cortex) feed to higher-order areas (orbitofrontal cortex,
thalamus, hypothalamus) and (what place is missing from that list?).
3. For mammalian olfaction, say something about EITHER (1) the domain structure
of each protein molecule OR (2) the intron-exon structure of each gene.
seven trans-membrane domains, no introns
4. Say something relating the richness of human olfactory sensation and
how it is related to the diversity of G protein coupled receptors.
substantial richness is mediated by nearly 1000 different GPCRs
5. In approximately how many spinal cord segments are the spinal motor neurons
for the gastrocnemius muscle?
five or six
6. Say something about mototopic organization of motor neurons in the ventral
proximal muscles are medial, flexors are dorsal
7. Where is the protein that is coded for by the Duchenne muscular dystrophy
around (outside) muscle membrane (and all over the place, e.g. brain)
8. In one figure, the axon of the alpha motor neuron is shown connecting
to "extrafusal" muscle fibers. ANSWER EITHER (1) What other type
of efferent motor neuron is shown? (2) What type of muscle do these other
nerves innervate? OR (3) What is the name of the compartment that houses
these other muscles?
gamma motor neuron, intrafusal muscle cells, muscle spindles
9. The basal ganglia do not send a tract down the spinal cord. How, then,
do they exert their motor control?
via thalamus and motor cortex
10. In Huntington's chorea, how is the positive influence of the thalamus
to the cerebral cortex affected?
it is increased
11. To explain the extrapyramidal motor system, your text showed the cerebral
cortex completely colored in except for the visual and auditory locations.
What did this represent?
areas that input to caudate and putamen
12. In a block diagram for Parkinson's disease, there are arrows. For instance,
a small arrow with a minus sign indicates diminished inhibition of the subthalamic
nucleus from the external segment of the globus pallidus. In this whole
cascade, only one change is primary, all the others are consequences. What
is that primary defect?
decreased dopamine from substantia nigra to caudate and putamen
13. Where is the pyramidal decussation?
caudal medulla (caudal to the trapezoid body, pyramid)
14. What is a major difference in how the primary motor cortex vs the cingulate
motor area innervates the face?
lower face from primary motor cortex is contralateral, upper face from cingulate
15. What cell type makes numerous contacts to each Purkinje cell?
16. Which nerve controls the greatest fraction of extraocular eye muscles?
17. The frog's eye connects to the visual part of the brain, the tectum.
In humans [answer either] (1) What is the tectum called? Or (2) What aspect
of vision does the human analog of the tectum subserve?
superior colliculus, eye movements
18. Say something about how the "gaze center" (PPRF) in the reticular
formation connects to the occulomotor nucleus.
via abducens nucleus, with a decussation
19. A cell from the mouse inner cell mass is treated for 4 days with retinoic
acid after 4 days without retinoic acid. This protocol converted the cell
from what kind of cell to what kind of cell?
from an embryonic stem cell to a neuronal precursor
20. Say something about the G protein in the FGF (or sevenless) signal transduction
called ras, small, monomer
21. What is the enzymatic activity of the receptor for bride of sevenless?
(Hint, same as for FGF)
phosphorylates tyrosine residues (kinase activity)
22. Mutants like antennapedia (that puts legs where the antennae should
be) or bithorax (that puts a second thoracic segment with wings next to
the normal one) are called (what?).
23. Here is a list of developmental ligands that signal to membrane receptors
then to the DNA: shh, FGF, BMP, Wnt, and boss. For ONE of these, give the
name of the membrane receptor.
patched, rtk, rsk, frizzled, sev
24. What is the difference at birth vs. at maturity of how many spinal motor
neurons can innervate one end plate?
at maturity, only one, more earlier
25. "The chick spinal cord generates an excess of neurons prior to
the differentiation and innervation of the limb. Normally some of these
neurons are lost..." Answer either (1) What is the evidence for the
first statement? or (2) Say something about this process of loss of neurons.
more neurons if supernumerary limb bud, less if ablated limb bud; apoptosis
26. Agrin and its receptor does (what?) in the development of (what model
of the synapse?).
it is involved in gathering the nicotinic receptors to the end plate of
the neuromuscular junction
27. Growth cones: ANSWER EITHER (1) How did Ramon y Cajal visualize them?
OR (2) How were they visualized in the confocal microscope?
silver staining technique of Golgi, actin in growing tips labeled with antibody
(like for GAP43) and a secondary antibody with a fluorescent tag
28. "Postmitotic neuroblast." Add detail concerning the exit of
the cell cycle.
exit at G1
29. Embryologists tell us that the retina and optic "nerve" are
part of the central nervous system. You were told that earlier in this course
too. Now add some details that justify that position.
optic vesicle becomes optic cup, outpocket from diencephalon
30. Brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and
neurotrophins 4 and 5 (NT-4/5). What is missing from this list of neurotrophins?
nerve growth factor
31. If you tried Sperry's experiment, turning the eye up-side-down and letting
it reconnect to the tectum, before stage 28, how would the frog respond
to a moving fly presented to the side of its visual field?
it would flick its tongue to the correct place
32. Why do they call classical (Pavlovian) and operant (instrumental) conditioning
stimulus and response are paired repeatedly
33. Why does RP and his friend who also had a stroke need to be very careful
because the foot tends to drop, it is easy to trip; might not be able to
stand back up; always thinking about what (s)he might crash in to when falling
34. Why did RP, our hemispatial neglect syndrome subject, think it was important
to relate his experience with pulmonary embolism?
clots cause stroke and p.e.
35. Following up on that last question, when would a previously healthy
person be most at risk for a pulmonary embolism?
after sitting still like when on an overseas flight
36. Describe the performance on the line bisection task in a patient with
hemispatial (contralateral) neglect syndrome.
nowhere near the middle
37. Patients with damage to what brain area have difficulty with the line
parietal, temporal, frontal, superior occipitofrontal fasciculus
38. The pyriform area is sometimes called the paleocortex, while the cerebral
cortex is sometimes called the neocortex. ANSWER EITHER (1) What is the
other area whose word ends in "cortex?" OR (2) What do we more
commonly call it?
39. Why is REM sleep called paradoxical sleep?
EEG resembles that of the aroused state
40. Explain in terms of Ashoff''s rule how the human free-running circadian
rhythm deviates from 24 hours.
it is longer than 24 hours when a diurnal animal is in the dark, it is like
the person is waiting for dawn
41. Say something about a visual pigment that could entrain a rhythm to
light in a mammal if all the rods and cones had degenerated
melanopsin, in ganglion cells, like an invertebrate rhodopsin, also expressed
42. A split-brain subject is shown an object in the right VISUAL field while
fixating on a dot straight ahead. How, if at all, does that information
reach Broca's area?
right eye's RETINAL field goes contralateral (to left cortex) at the chiasm,
left eye's stays ipsilateral, so it IS on the correct side
43. How is it that ubiquitin hydrolase can turn sensitization into a long
by breaking down the regulatory unit, PKA activation lasts longer
44. "After a train of stimuli to axons of CA3 pyramidal axons (Schaffer
collaterals) the response of the postsynaptic cell (CA1 pyramidal neuron)
is larger." Answer either (1) What is this simple kind of learning
called? or (2) What part of the brain was being studied?
long term (lasting) potentiation, hippocampus
45. After half an hour in a dark room, you are much more sensitive. After
a prolonged forceful muscle contraction, that contraction becomes weaker.
Why is Kandel's work on habituation of the gill withdrawal reflex considered
a model of learning while the other two examples are not?
at a synapse, not receptor adaptation or motor fatigue
46. What is the difference in either [(1) the appearance of - or - (2) the
way the brain mediates] a pyramidal smile vs. a Duchenne smile?
inability to will a symmetrical smile in involuntary response to humor
47. The discoveries of long (29 hr) and short (19 hr) per (period) mutants
paved the way to the characterization of how the PER gene and the protein
it encodes function in the non-mutant animal. How does PER contribute to
the biological clock?
the PER mRNA and protein increase and decrease on a daily cycle
48. Cannon coined the term "fight or flight." What the heck? Those
two things are not the same, so why would he lump them together and we quote
him for the next century?
they both are enhanced through action of the sympathetic nervous system
49. Say something about how you prepare a rat to demonstrate that electrical
stimulation of the brain can serve as a positive reinforcer in an operant
get an approved animal protocol, anesthetize, put in stereotaxic apparatus,
using bregma and lambda and the atlas, find the hypothalamus, put in a double
electrode insulated except at the tip, mount it to the head, sew up the
wound, let the animal recover, put it in a Skinner box, plug it in and turn
on the program
50. "Circulating testosterone is what makes 5 year old boys' behavior
different from that of 5 year old girls." Support or contest that statement.
there is none, it is perinatal levels that had a permanent organizing effect
51. How is the somatosensory cortex different for non-lactating vs lactating
there is a larger representation for the ventrum (where the nipples are)
52. What does the story about the sex change operation of a young twin after
a mishap in the circumcision operation tell us about gender identity?
it is not based on upbringing as much as previously thought, more biology
53. Testosterone under the skin of a female rat pup would do what to the
feeding behavior when she is an adult?
feeding would be more like that of a male, animal would get heavier than
54. With a technique as crude as the ERG (electroretinogram), how is it
possible to make conclusions about the specific properties of R1-6, R7 and
R8 when the electrode records the responses of all of those receptors?
mutants like sevenless and rdgB, the latter eliminating R1-6 systematically
simplify the retina
55. What visual capability do Drosophila and people missing a lens have
(that you do not have)?
sensitivity to ultraviolet light
56. In Drosophila, autophagy via coated vesicles, multivesicular bodies
and lysosomes characterizes turnover of photoreceptive membrane. Say something
about how turnover in vertebrate photoreceptors is handled.
tips of rods are shed, phagocytosed by pigment epithelium, undigested turns
to lipofuscin, new disks are made at base of rod
57. People and flies get vitamin A (and other important molecules) through
dietary carotenoids. Name one.
beta carotene, lutein, zeaxanthin
58. Earlier this semester, you learned that a cGMP-gated channel that, if
mutated, led to congenital stationary night blindness mediated phototransduction
in the vertebrate rod. What is the channel in the Drosophila visual receptor?
59. Why do human retinal pigment epithelial cells accumulate lipofuscin,
the aging pigment?
for a lifetime (since RPE cells are not replenished by mitosis), they phagocytose
the sloughed tips of rods, and lipofuscin is the indigestible residue of
the phagolysosomal system
60. Why was it important to demonstrate that Brenda Milner's patient HM,
with his bilateral hippocampal lesions, could learn to draw using a reflection
in a mirror?
demonstrates that non-declarative memory (motor skill) is not as impaired
as declarative memory
61. A pigeon learns well in a Skinner box and then is retired for many years
in a home cage. Placed back in the Skinner box for the first time after
many years, what is the performance like and why?
it is at the level years earlier suggesting that forgetting is not as important
62. Beta and gamma secretases cut (what?) into (what?) relevant to memory.
amyloid precursor protein into beta amyloid
63. Explain why the term "working memory" applies to the radial
8-arm maze task.
without any defined pathway, the rat knows which of the arms (s)he has visited
so as to get all 8 pellets without repeating an arm
64. According to Sperry, why MIGHT one think that "real mental freedom
to act and choose is only an illusion?"
"materialistic science holds that a complete explanation of brain function
is possible in purely objective physiological and biophysical terms."
65. Prof. Stark (and you, he hopes) are convinced that human behavior is
not predetermined. How did Nobelist Roger Sperry contribute to this conviction?
although "materialistic science holds that a complete explanation of
brain function is possible in purely objective physiological and biophysical
terms" "the simpler electric, atomic, molecular, and cellular
forces and laws, though still present and operating, have been superseded
by the configurational forces of higher-level mechanisms" in other
words there are emergent properties.
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this page was last revised May 5, 2017