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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 horn.

proximal muscles are medial, flexors are dorsal

7. Where is the protein that is coded for by the Duchenne muscular dystrophy gene?

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 is bilateral

15. What cell type makes numerous contacts to each Purkinje cell?

granule cell

16. Which nerve controls the greatest fraction of extraocular eye muscles?

occulomotor (III)

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 cascade.

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?).

homeotic mutants

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 "associative learning?"

stimulus and response are paired repeatedly

33. Why does RP and his friend who also had a stroke need to be very careful walking?

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 bisection task?

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?

archicortex, hippocampus

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 in melanophores

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 term phenomenon?

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 conditioning paradigm.

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 female rats?

there is a larger representation for the ventrum (where the nipples are) if lactation

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 a female

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 as extinction

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