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BIOL-415 Nerve cell mechanisms in behavior
BIOL-615 Neural bases of behavior
Second test - Thursday, April 3, 2008 - Prof. Stark
All questions are short answer. 65 points total.


For questions 1-5, refer here

1. The dissection reveals the brachium pontis, the brachium conjunctivum and Answer either (1) the third part. Or (2) the whole structure (all three put together).

restiform body (inferior cerebellar peduncle), cerebellar peduncle

2. Rostral to the above, in the midbrain, is the lamina quadrigemina. Answer either (1) the function of the inferior pair. Or (2) the function of the superior pair.

auditory center, visual center

3. Answer either (1) name or number of this nerve. Or (2) a specific function other than somatic motor control.

occulomotor (III), autonomic (pupil and accomodation)

4. What is the artery that feeds the circle of Willis?

internal carotid

5. Answer either (1) What is the function of the axons you see here? Or (2) What is the name given to the structure delineated here?

(pyramidal) motor system (corticospinal tract), trapezoid body

For questions 6-11, refer here

6. If you could see through the optic chiasm, what diencephalic structure would you be seeing?

hypothalamus (suprachiasmatic nucleus)

7. Tracts branching from what huge white matter structure give rise to this striated appearance?

internal capsule

8. "Periaqueductal gray" where the aqueduct connects what two numbered ventricles?

3rd and 4th

9. Here's a place you've heard of. (hint, the site of action of N-acetyltransferase and hydroxy indole O-methyl transferase)

pineal

10. Looks like we missed "mid" in this midsagittal cut by a bit. What nucleus would we see in the lateral ventricle on the other side?

caudate

11. What is this white matter?

optic chiasm

For questions 12-15, refer here

12. What is this white matter?

internal capsule (corona radiata)

13. You had a difficult time peeling off this tough layer called (what?).

dura mater

14. In addition to the fornix, what white matter from the fimbria is found in this area?

hippocampal commisure

15. If we tear through this (what is this?), we will see (answer to #10).

septum pellucidum

16. You have a rat in a stereotactic instrument. How do you decide where to drill the hole through the skull to reach a specific location?

a stereotactic atlas tells you the location relative to (XY) bone suture (lamda and bregma) and depth (Z)

17. With a stereotactic instrument, you aim for the medial nucleus of the hypothalamus and make a lesion (and collect data on the animal's weight for a few months). How can you know whether you hit your intended target?

You must do histology on the brain to see if the lesion is near the intended target (as identified in the atlas)

18. Part of the human retina projects to the contralateral lateral geniculate nucleus. The other part projects to the (what?) lateral geniculate nucleus.

ipsilateral, duh

19. You can contract Creutzfeld Jacob disease by eating contaminated tissue. Why is the current hypothesis explaining the spread of such diseases so contradogmatic with respect to infectious diseases?

no nucleic acids are involved, only protein, and even here, it is conformation that is critical

20. Using a term such as "myelencephalon," where is the frog's optic tectum?

mesencephalon

21. There are sensory and motor functions for the cranial nerves. In addition to striated muscle control, what other kind of motor control do the cranial nerves subserve?

parasympathetic autonomic

22. "The thalamus is a major relay station" [yes, I know that is an oversimplification] "for the motor system and for (what?)."

sensory systems as they project to the cortex

23. Why is the medial forbrain bundle called bundle instead of tract?

It is a collection of different tracts with different functions traversing together

24. "When you dip your face in water, parasympathetic and sympathetic changes mediate the diving response" caused by sensory input from what nerve?

trigeminal (5)

25. "The fimbria forms the fornix" and also it makes (what big gray area?) look white.

hi[ppocampus

26. Answer one of these: (1) Why would you need to use a different method of lesioning to study the behavioral effects of lesions of the hippocampus (compared with, say, the ventromedial nucleus of the hypothalamus). Or (2) how would you do such lesioning?

(1) it is huge, (2) use suction (or a lot of electrolytic lesions

27. What, specifically, takes up more space in the cervical and lumbar enlargements?

spinal motorneurons

28. What is the function of the choroid plexus?

secrete cerebrospinal fluid

29. The brainstem is considered to be the midbrain, the medulla, and (what?)

pons

30. The more conventional name for the archipallium.

hippocampus

31. How does a famous "second messenger" activate protein kinase A (PKA)?

4 cAMPs bind 2 inhibitory subunits and pull them off of 2 catalytic subunits

32. With the assistance of CREB (cAMP response element binding protein), Answer either (1) what enzyme acts on (2) what macromolecule to medeiate transcription.

RNA polymerase acts on DNA

33. For what specific aspect of mechanosensation would the rapid adaptation of Meissner's corpuscles be useful?

active (feeling) touch (of a textured surface)

34. Answer either (1) gamma motor neurons innervate what specific type of cell? Or (2) what is the function of this activation?

intrafusal muscle fibers, preset the stretch of the stretch receptor

35. Capsaicin activates a channel that normally functions to detect (what?).

heat

36. "First pain" and "second pain." What is the axonal difference?

A delta (small, myelinated) vs C (small, unmyelinated

37. What is the function of the cell that is stimulated by bradykinin?

pain

38. The head of a neurosurgery patient is opened to expose the brain using only local anesthetic. Answer either: (1) How do they get away with that? Or (2) Why would they do it that way?

no pain receptors in the brain, to make certain they are not messing with a really critical function

39. There is a cell body in the dorsal root ganglion for touch (not pain) input. Where are the "beginning" and also the synaptic terminals of this cell?

beginning - the receptor itself, end - dorsal column (cuneate and gracile) nuclei

40. In what way are the functions of the cuneate and gracile nuclei different?

cuneate upper body, gracile lower body

41. Before it reaches the thalamus, but after it enters the central nervous system, in what way does pain and temperature information from the face differ in its pathway from mechanosensory informationfrom the face?

Strangely, for pain, the pathway first descends (from the pons to the medulla)

42. The mean two-point discrimination threshold for the fingers is less than 5 for the fingers and more than 45 for the calf. Units?

mm

43. The VPL of the thalamus connects to the somatosensory cortex. What does VPL stand for?

ventral posterior lateral

44. The Raphe nucleus and the reticular formation feed to a cell in the dorsal horn in the gray matter of the spinal cord for what purpose?

to modulate pain where it inputs

45. The conjugated double bond system of 11-cis retinal loosens up and the chromophore relaxes to the all-trans configuration. What causes that loosening?

excitation by light

46. Zonule fibers ("ligaments") answer either: (1) connect the lens to (what?), or (2) to mediate (what?).

ciliary muscle, accomodation

47. Say something about vision in either (1) the ultraviolet; or (2) the infrared.

UV - insects have, people usually do not b/c lens absorbs UV; IR - snakes have pit "eyes" to detect warm blooded prey

48. Why would you go blind with poorly controlled diabetes?

angiogenesis

49. What was the Nobel Prize - winning finding of Hartline in Limulus relating to Mach bands and lateral inhibition?

neural firing pattern accentuates light-dark boundary

50. Explain why blindness in retinitis pigmentosa is witnessed by a ring scotoma (tunnel vision).

rods go first and rods are localized in the mid-peripheral retina

51. Labeled amino acids are incorporated into rod outer segment proteins. What is the significance of the movement of the band of label over the next two weeks?

new disks are made and old ones are shed and phagocytosed (by the RPE)

52. This question relates to the evolution of protein families, for example the G protein linked receptor. At one point on an evolutionary time scale, there is one gene, later two, example those coding for the long and middle wavelength rhodopsins. How do they think one gave rise to two?

unequal crossing over

53. Why would there be a current along the outside of a rod from the inner segment to the outer segment in the dark?

ion pumps and the ATP that powers them are in the inner segment while channels for those ions are in the outer segment

54. Why would the release of the neurotransmitter glutamate be decreased when the rod is stimulated with light?

because the rod is hyperpolarized

55. You went home and tried what I suggested, shined a flashlight to one eye. Alas, only one pupil constricts. Tell me a place where you have nerve damage.

has to be after the pretectum. maybe between the pretectum and the Edinger-Westphal nucleus (one of two paths) or from there to the ciliary ganglion, to the muscle (on one side)

56. If Hubel and Wiesel had looked for a grandmother cell instead of the cells they identified (e.g. simple cell), why wouldn't they have gotten a Nobel Prize?

Their systematic approach was very productive, good thing they didn't start looking for a needle in a haystack

57. How were the ocular dominance columns in normal and visually deprived animals visualized?

audioradiography, histological slices exposed photographic "film"

58. The human audibility curve is the threshold for hearing as a function of frequency. The Y axis could be plotted as intensity in dynes per square centimeter (plotted logarithmically from 0.0001 to 100) or, alternatively, what more customary term for intensity (from 0 to 120)?

decibels

59. Answer either: (1) what the tonotopic organization of the primary auditory cortex looks like; or (2) how would you demonstrate the tonotopic organization of the primary auditory cortex?

cells that respond to low frequency at one end, high at the other, record from places and run through a range of stimulus frequencies and see which frequency each place responds to best

60. What causes the channels that mediate hearing to open?

mechanosensitive, would be membrane deformation, assisted by tip links

61. While jogging, you trip and start to fall. Name a sensory organ or a spinal pathway involved in the elicited responses of your spinal motor neurons.

vestibular apparatus, vestibulospinal tract

62. "Three SNPs associated with PTC insensitivity: A49P, V262A, I296V." Translate either (1) SNP, (2) PTC or (3) A49P, V262A, I296V.

single nucleotide polymorphism (genetic change), a bitter chemical tastant for which there are tasters and non-tasters (based on a gene) in humans, the number is the amino acid position - the first letter is the normal amino acid, the second letter is what it is changed to

63. What kind of molecule (e.g. enzyme, pump, heterotrimeric G protein) are - Answer for either of these molecules involved in taste transduction: (1) T1R2, or (2) TRPM5?

G protein coupled receptor, channel

64. In an adult human, a new olfactory receptor cell is "born." How does it "decide" which glomerulus to connect to?

based on the G protein coupled receptor it binds to, it connects to a glomerulus collecting information from receptors expressing the same receptor molecule

65. Answer either (1) How did cAMP get to be higher after an odorand binds the receptor molecule? Or (2) What does that cAMP do to change the cell's electrical potential?

the alpha subunit of the G protein (Golf) activates adenylyl cyclase, it is the ligand for a calcium channel

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