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BIOL 415 Nerve cell mechanisms in behavior
BIOL 615 Neural bases of behavior
Test 2 March 31, 2011 - Prof. Stark
All questions are short answer. 65 points total

1. "Tetrahydrocannabinol (THC) binds to CB receptors to mediate the effects of marijuana." Regarding the endogenous transmitters, answer either (1) Characterize the chemical PRECURSOR of one of these transmitters. Or (2) Where (in the cell) would this PRECURSOR be found?

membrane phospholipid, membrane

2. A poisonous snake, the banded Krait (Bungarus) bites its prey. Answer either (1) What effect does the venom have on the prey? (2) It has this effect by binding what specific neurotransmitter receptor? Or (3) Where are these affected receptors located?

paralyse, nicotinic, neuromuscular junction

3. A extensive table with all the possible components for ionotropic receptors for lots of neurotransmitters was shown to you. Why were dopamine and norepinephrine not on this table?

there are no channel receptors for dopamine or norepinephrine

4. The NMDA receptor (answer either) (1) is for what transmitter? Or (2) passes sodium, potassium and (what other important ion?).

glutamate, calcium

5. Answer either: The second and third cytoplasmic loops (and what terminal?) of the beta adrenergic receptor interact with (What is the next downstream molecule in this cascade?).

C terminal, G protein

6. The activated alpha subunit activates adenylyl cyclase. Answer either (1) Why would you expect it to remain attached to the inside of the membrane? Or (2) What has to happen before the activated alpha subunit reassociates with the beta-gamma subunits?

it is bound to the membrane, it turns ATP into ADP

7. "In this situation, atropine would save your life." What situation? And why would it save your life? (Answer both.)

poisoning with malathion, block acetylcholine receptors on tyhe heart, prevent it from stopping

8. "IP3 is a ligand for a channel." Answer either (1) For what ion? Or (2) On what membrane?

calcium, smooth endoplasmic reticulum

9. Whereas cAMP is known for actions such as gating a channel, it can also regulate the transcription of DNA into mRNA. Name one of the proteins intermediate between cAMP and RNA polymerase.

PKA, CREB

10. Caffeine inhibits what enzyme?

PDE

11. How did Pruisinger propose that a protein (without DNA or RNA) can be infectious and alter the proteins in the victim, making those proteins infectious.

protein in scrapie configuration converts protein in control configuration into the scrapie form

12. Other than cerebral cortex, name a major component of the telencephalon.

basal ganglia, hippocampus, olfactory bulb, basal forebrain

13. The oculomotor nerve (cranial nerve #3) has strictly motor function. State one of the other motor functions (other than connections to striated muscle associated with the eye).

accomodation, pupillary reflex

14. For striatum or lenticular nucleus, explain how the body got its name.

striated because of branches of internal capsule, shaped like a convex lens in horizontal section

(for # 15-19) go here

15. Give a name, number or function of the cranial nerve indicated.

occulomotor, 3, eye movement, pupil, accomodation

16. Give the function (for both) or a name (for either) area of white matter indicated .

outgoing voluntary motor tract, trapezoid body, trapezoid body

17. What is this white area called?

pons

18. Answer either (1) What is this structure called? Or (2) Say one of the things you would see if you removed that structure.

septum pellucidum, head of the caudate and lateral ventrical

19. What is this area called?

hypothalamus, third ventrical

(#s 20-24) go here

20. What is this white matter called?

internal capsule

21. What is this large structure in the middle of the brain called?

thalamus

22. What is this white matter called?

corpus callosum

23. What is the white matter on the outside of this structure called? (Alternatively, you could say one of the tracts on the midsagittal slice you see that are formed from these axons.)

fimbria, fornix, hippocampal commisure

24. What white matter is being ripped here?

(#s 25-29) go here

25. What kind of information is being carried by this tract?

olfactory

26. What is this cross-over structure called?

optic chiasm

27. What is this large area of the brain called?

cerebellum

28. You definitely saw this huge nerve in your dissection (pointed to twice). Give a name or number. Hint: there are 3 branches coming in from touch sensation in the the face.

trigeminal, 5

29. What is the name associated with the gray matter you needed to scrape away (from the mid-sagittal plane) to reveal this tract?

massa intermedia, thalamus

30. Stimulation of 9 square mm of skin affects one Merkl disk; by contrast, stimulation of 60 square mm of skin affects one Ruffini end organ. Thus the Ruffini has a larger (what is the expression?) than the Merkl.

receptive field

31. Feature detection is the expression for the processing of sensory input so that reduced information is passed along to the next higher level in the nervous system. Drawing an analogy to the visual system, I argued that it is easy to locate a gentle tap to the forearm even though all the flesh that jiggles is actually stimulated. What is the expression for the type of neural interaction that mediates this feature detection?

lateral inhibition

32. The afferent from a nociceptor has its cell body in the dorsal root ganglion. Where is the first synapse? (Answer both: location plus which side, using the appropriate term to answer which side.)

dorsal horn gray matter ipsilateral

33. Ia, II and A-beta are among the afferent axon types. Give me either [(1) the designation or (2) a specific function] of a slower afferent axon type.

A-delta, C, pain, temperature

34. For proprioception and the stretch reflex, give the specific name of either [(1) one of the two types of intrafusal muscle fibers, or (2) the fusimotor efferent axon].

nuclear chain or nuclear bag fiber, gamma motor neuron

35. A VR-1 receptor is a ligand-gated channel for which capsaicin is the ligand. Answer either: (1) What is the more natural stimulus that affects this channel? Or (2) What was the original member of this channel family called when it was discovered to be deficient in a Drosophila visual mutant?

warm, transient receptor potential

36. There is a synapse in the gracile or cuneate nucleus. Answer either (1) Where is the "beginning" of the cell that makes the synapse? Or (2) Name one type of receptor that sends information in on this pathway.

touch, in the skin, Merkl, Meisner, Ruffini, Pacinian, stretch receptor

37. The anterolateral system is for pain. There is a notable exception (in terms of spinal tract location). Answer either (1) What type of pain is carried in this exceptional tract? Or (2) Where in the spinal cord is it carried?

viceral, dorsal columns at midline

38. Tell me a place where the 2-point discrimination threshold for fine touch is less than 5 mm.

fingertips, lips, tongue

39. Name a transmitter used in a microcircuit in the dorsal (posterior) horn gray matter (substantia gelatinosa).

glutamate, enkephalin, substance P

40. "Light briefly loosens up the bonding orbitals of this chromophore." Answer either (1) What is the chemical that makes this visual pigment a pigment? Or (2) What is the word for the whole molecule, the prototypical member of the G protein coupled receptor superfamily?

vitamin A, specifically 11-cis retinal, rhodopsin

41. A person who had had emmetropia (normal vision) developed hyperopia. Another person who had had emmetropia developed presbyopia. Answer either (1) What kind of corrective lens would help in both situations? Or (2) What is the difference in these two disorders?

convex lens, hyperopia is far sightedness person would always wear glasses, presbyopia is loss of accomodation, person would need reading glasses

42. The aqueous humor does not drain sufficiently. Answer either (1) What is this disorder called? Or (2) What cells die, causing blindness?

glaucoma, ganglion cells

43. In what disorder does angiogenesis contribute to blindness?

diabetic retinopathy, also wet age related macular dystrophy

44. "Mutations of proteins of the visual transduction cascade cause retinitis pigmentosa." I never listed specific molecules, but you should know enough to tell me one.

rhodopsin, transducin, PDE, channel

45. A radioactive amino acid allowed the rod outer segment disks closest to the inner segment to be labeled. On the basis of this methodology, what fundamental finding ensued?

that new outer segment is continuously made, the outer segment turns over, old outer segment is phagocytosed by the retinal pigment epithelium

46. Presumably, New World monkeys have one rhodopsin coded for on the X chromosome while Old World monkeys (and apes and humans) have two (or more). How did this happen?

unequal crossing over

47. In terms of cGMP levels, explain why the rod hyperpolarizes in response to light.

With the cation channel continuously gated by cGMP in the dark, the cell is depolarized, and when PDE is activated in phototransduction, the channel closes because cGMP has been turned into 5' GMP

48. Dark spots moving against a light background cause some ganglion cells in the frog retina to fire. Explain why this was considered an important finding.

it shows feature detection of a biologically relevant stimulus, bug detectors

49. A stroke wipes out the connection of the pretectum to the contralateral Edinger-Westphal nucleus but not to the ipsilateral one. How could you infer this with a very simple non-invasive vision test on a cooperative subject?

There would still be a pupillary reflex but not in the contralateral eye

50. Say something about how the nasal portion of the retina projects to the lateral geniculate nucleus

nasal retina connects to contralateral LGN's layers 1, 4, and 6.

51. An electrode is in a simple cell that fires action potentials vigorously when stimulated with a thin, vertical stripe of light. How does it respond to a thick stripe in the same location, and why does it react that way?

a lot less or not at all b/c the thick stripe also stimulates the inhibitory surround

52. Injection into one eye followed by a specialized histological technique demonstrated a zebra-stripe pattern of ocular dominance columns in the visual cortex. Answer either (1) What was injected in the eye? Or (2) What technique was used for the visualization in the cortex?

a radioactive amino acke, audioradiography

53. The human audibility curve plots Y as a function of X. Answer either what is on the Y OR X axes.

ordinate is threshold plotted in intensity, plotted logarythmically, abscissa is frequency in Hz where log plotting is for convenience

54. What is the relevance of the value 0.0002 dynes/cm2 in hearing?

that is the denominator, the pressure standard in defining dB

55. What is the relevance of the value 20,000 Hz in human and animal hearing?

it is the upper limit of frequency for hearing by young people, above that is ultrasound that dogs and bats can hear

56. Pressure is passed from the scala vestibuli through the helicotrema (cochlear apex) to the scala tympani and released at the round window. The pressure is delivered to the cochlea by (name the third [final] bone OR the "membrane" [inner ear drum]).

stirrup=stapes, oval window

57. Cells in the auditory cortex are responsive to a narrow range of frequencies. By contrast, the tuning curve for a cell in cranial nerve VIII is wider. Bekesy, the Nobel Prize winner, argued that this was because of what type of processing?

lateral inhibition

58. A figure was shown to you with hair cells and the axons they are connected to. On the basis of how that figure was labeled, it was stated that outer hair cells do not function as receptors. What was it about the axons connected to outer hair cells that raised this issue?

those axons were called efferent

59. Tip links assist channels (answer either) (1) for what ion? Or (2) located on what specific subcellular component?

K+, stereocilium

60. Regarding the inferior colliculus, answer either (1) It's cells synapse where? Or (2) It receives input from what nucleus?

auditory cortes, cochlear nucleus and olive

61. How do insectivorous bats use sound to catch their prey?

echolocation (sonar)

62. In addition to input from vestibular apparatus, the vestibular nuclei that form the vestibulo-spinal tracts receive input from what major brain location?

cerebellum

63. In the sense of taste, for sweet and for amino acids, what was unique about the G protein coupled receptor?

it is a dimer

64. Regarding IP3 for umami and bitter taste receptor cells, answer either (1) What enzyme made IP3? or (2) What is the type of channel gated by IP3?

PLC, for calcium

65. In addition to the 5 primaries for taste stimulation, with input via cranial nerves VII, IX an X, it is argued that stimulants like capsaicin contribute to our overall appreciation of gustation. Answer either (1) Which cranial nerve is used? Or (2) What is the term for the receptor type?

5 trigeminal, polymodal nociceptive

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