1. With your "orange stick," you scrape all the gray matter out of one sulcus. Answer either (1) How can you tell what direction the myelinated axons run? or (2) Where do the first axons you find come from and go to?

stick glides in axon direction and scrapes across the grain, from and to the adjacent gyri

2. In the corticospinal tract, these motor cells in the precentral gyrus make their first synapse (where?).

to the spinal motor neuron in the ventral horn

3. You have a rat brain atlas and your anesthetized rat (in an approved protocol) is mounted in a stereotactic device with the skull exposed. Say something about what you need to do to get the tip of an electrode into the ventromedial nucleus of the hypothalamus.

measure from the bone sutures*, drill a hole, lower the electrode to the correct depth*, *=requires consulting the atlas

4. Before Pruissinger's prion hypothesis... answer either (1) What kind of disease? was explained by Nobelist Gadjusec by a virus? (2) A virus with what special kind of properties?

spongiform encephalitis, CJD, kuru, etc.; slow

5. The medial forebrain bundle goes through the lateral hypothalamus and includes [answer either] (what famous tract?) that is disupted in (what disease?).

nigrostriatal tract, Parkinson's

6. What do you have to cut off to see the floor of the fourth ventricle?


7. The left side of the cerebellum controls which side of the body?


8. "Massa intermedia" is an operational term for what major relay structure in the brain?


9. If you miss the midsagittal cut a tiny bit... Name one of the three tracts you would see where the thalamus is located.

fornix, mamillothalamic tract, habenulopeduncular tract

For questions 10-13, see this figure

10. Name this structure (or give it's cranial nerve number)

olfactory bulb, I

11. This white matter is seen in the midsaggital view as... (name either of the two tracts).

fornix, hippocampal comisure

12. What is this artery that feeds the circle of Willis?

internal carotid

13. What is this structure?

lateral geniculate nucleus (thalamus)

For questions 14-21, see this figure

14. These fibers, hidden as they pass under the pons, form what tract?

corticospinal, pyramidal

15. Here it is called the pons. What do you call these fibers, on the "other side," in the dissection of the 3 components of the cerebellar peduncle?

brachium pontis or middle cerebellar peduncle

16. This one nucleus is in a system with two others. Name one of the two OTHER nuclei.

putamen, globis pallidus

17. What is the frog's equivalent of this structure?

optic tectum

18. What is this major body of white matter called?

internal capsule

19. What was revealed after you removed this important limbic structure wrapped in myelinated axons (i.e. under the structure you removed)?


20. The brains provided for your dissection still had this white "membrane" (called what?) that you were required to remove before proceeding.

dura mater

21. For this figure, answer either (1) What is it called when the entire white matter under the cortical layers is exposed? or (2) What is the term used for these particular axons?

corona radiata, arcuate fibers

22. After C-type sensory afferents arrive in the spinal cord, the projection of this information ought to ascend in what portion of the spinal cord?


23. Why would you expect a Pacinian corpuscle to have a large receptive field?

since it is deep, deflection of a large area of skin would stimulate it

24. For either (1) Group I and II afferent axons or (2) Gamma motor neurons, state what is feeding into it (for 1) or what it feeds to (for (2).

stretch receptors, intrafusal muscles

25. Capsaicin stimulates the VR-1 receptor. Answer either (1) What would be the "normal" (biologically relevant) stimulus? (2) What related Drosophila mutant was discovered much earlier? or (3) Say something about the molecular structure of this receptor.

heat, transient receptor potential, channel

26. What is the difference between the gracile and cuneate tracts?

gracile is information from lower limbs, cuneate from upper

27. Why isn't the face included in the diagram of dermatomes?

trigeminal cranial nerve input is separate from segmented spinal cord input

28. In terms of axon type, what is the difference in the neospinothalamic tract vs the paleospinothalamic tract?

neo A delta, paleo C

29. Most pain from the lower body travels in the anterolateral tracts. For the exception, answer either (1) What kind of pain travels elsewhere? (2) Where does it travel?

viceral pain, dorsal columns

30. The two point discrimination threshold is 3 mm for the index finger and 45 mm for the calf. The tongue was not in the textbook figure, but you should be able to give me that number here.

probably about 3 like the finger

31. The trigeminothalamic tract carries what particular type of information?

touch, pain, etc from the face

32. Your coverage in this course gave you only one neuron that releases eckephalin. Where is it located?

dorsal horn, substantia gelatinosa

33. In what way is Planck's constant relevant to calculations concerning light?

used to calculate energy of one photon

34. Say something about why vision, as we know it, would not work for wavelengths far below or above "visible wavelengths."

too short is ionizing (also cut off by ozone layer), just right excites electrons, too long vibrates molecules (heat is waste)

35. "The cornea is the strongest lens in the eye." Explain this in terms of relative indices of refraction.

the air to cornea interface is the only large difference in index of refraction, so the corneal curve has a profound effect

36. For what visual disorder is angiogenesis an underlying cause?

diabetic retinopathy

37. "Foveal cones are protected from blue light" (by what?).

macular pigments (zeaxanthin and lutein)

38. A paper published in 1942 demonstrated that a rod can respond to a single photon of light. Say something about the methodology in this study.

human subject answered if he could see carefully calibrated 500 nm light; 6-14 quanta were absorbed by a 500 rod area (psychophysics)

39. Histological autoradiography demonstrated that a radioactive amino acid was incorporated into those disks of the outer segment nearest to the inner segment. What eventually happened to this band of radioactivity?

over a few weeks, it moved up the outer segment until those disks were shed and phagocytosed by the RPE

40. Say something about how there came to be genes for two of the cone rhodopsins on the X chromosome in people.

in reevolution of mammalian colover fision after it was lost in an evolutionary bottleneck, unequal crossing over in meiosis happened along the line, a difference from old to new world monkeys

41. It might be better to say that "Light stops photoreceptor depolarization" than to say "Light causes photoreceptors to hyperpolarize." Justify.

in the dark, cGMP keeps sodium-calcium channels open

42. Why is there lots of cGMP in a rod in the dark?

PDE is not activated

43. How was the horseshoe crab Limulus used to show how contrast detection was enhanced by feature detection?

neural input from ommatidia at a light-dark boundry show a more accentuated gradient of activity

44. Hubel and Wiesel referred to a cell in the striate cortex as "simple" if it responded best to a line at an angle. Name one of the additional properties of the cell's properties that earned it the designation of "complex" or "hypercomplex."

line at an angle has to move in a preferred direction, or line must end (have a corner)

45. On the way to the thalamus, what is different about axons from the nasal vs the temporal retina at the optic chiasm?

temporal stays ipsilateral, nasal crosses to contralateral

46. For the ciliary ganglion, answer either (1) Where is the preganglionic neuron's cell body? or (2) At the neuro-effector junction, what is the effector?

edinger-westfall nucleus, iris (or ciliary muscle)

47. What is different about layers 1,4 & 6 vs 2, 3, & 5 of the lateral geniculate nucleus?

connected from contralateral vs ipsilateral retinas

48. A person is born with a cataract in one eye. What else will go wrong if this situation is not remedied immediately?

the cortex will become blind to input from that eye

49. In a follow-up to Hubel and Wiesel's electrophysiology, what happened to radioactive proteins made from an injection into one eye at the synapse in the thalamus?

they crossed to postsynaptic cells

50. As an electrode is advanced across the primary visual cortex obliquely, what changes in cell response properties are observed in addition to crossing ocular dominance columns are observed?

preferred angle changes

51. Simple cells respond to a line at an angle. These cells presumably receive inputs from an organized subset of lateral geniculate neurons whose receptive field organization is (what?).


52. In the frequency discrimination demonstration, why was it important to hold both tuning forks to one ear simultaneously?

to show, using beats, that they differed by just a few Hz

53. Why did Bekesy need to invoke lateral inhibition to make his data dovetail with Helmholtz's place theory?

data showed that place localization on the basilar membrane was too crude

54. How does a kinocilium differ from a stereocilium?

kinocilium is a real cilium, not present in human adult hair cells, only one kinocilium

55. You have an electrode on a nerve in the auditory pathway and obtain the data for a tuning curve. What are the axes of your graph?

X - frequency, Y dB

56. Mechanoreceptive channels in auditory hair cells are assisted by what structural specialization?

tip links, extracellular protein from one stereocilium to its neighbor

57. In addition to potassium channels, what other channels are important in the transmission of input from the human auditory receptor cell?

calcium, also trp

58. Where is the first place in the auditory projection that receives bilateral input?

superior olive (mid-pons)

59. Say something about how a bat decides to cross paths with a moth but does not make the mistake of crashing into a wall.

the moth would make a small echo that would vary in intensity

60. Name (or give the number for) an efferent cranial nerve that would mediate eye movements controlled through the vestibular system.

occulomotor III, abducens VI (also trochlear IV)

61. How does a taste bud relate to a papilla?

there are many taste buds in a papilla

62. Bitter taste receptors are what kind of molecule?

g protein coupled receptor, T2R, TRA2R would be acceptable

63. The solitary nucleus gets input from nerves VII, IX and X, and it feeds to the thalamus and (say another place).

amygdala, hypothalamus

64. In addition to the 5 primary taste receptors that input via nerves VII, IX and X, say something about either the chemical ("tastant") or the receptor type, or the nerve input mediating appreciation of food at the level of watery stimulation in the mouth.

capsacin, polymodal niciceptive fibers, V = trigeminal

65. A male moth is excited by a female's sex attractant pheromone at a concentration of one molecule per cubic foot. How does he know which way to fly?

up wind