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BIOL 415 Nerve cell mechanisms in behavior

BIOL 615 Neural bases of behavior

Final Exam Thursday May 8, 2014 – Prof. Stark

All questions are short answer. 65 points total

 

1. What is the intracellular ligand that opens the olfactory receptor sodium-calcium channel from inside the cell?

 

cAMP

 

2. 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

 

3. In the olfactory projection, pyriform cortex, olfactory tubercle, amygdala and entorhinal cortex feed to orbitofrontal cortex, thalamus and… (fill in EITHER of the TWO locations missing from that list).

 

hypothalamus, hippocampal formation

 

4. For either the t-tubule or the sarcoplasmic reticulum, give the pharmacological name for the calcium channel.

 

dihydropyridine receptor, ryanodine receptor

 

5. How is it that stretch in the bicep would lead to inhibition in the tricep?

 

there is an inhibitory interneuron in the reflex arc

 

6. A defect in which cells leads to the motor demise of people with Lou Gehrig’s disease?

 

spinal motor neurons

 

7. ANSWER EITHER (1) Where is the pyramidal decussation? OR (2) In the Brown Sequard syndrome, which somatosensory system would have an ipsilateral impairment below a half spinal cord injury (as would be the case for motor impairment)?

 

medulla lemniscal

 

8. A portion of the precentral gyrus controls muscles in the contralateral lower part of the face. In addition, another part (which part?) of the cerebral cortex controls the upper part of the face bilaterally.

 

cingulate

 

9. The tectospinal tract connects ANSWER EITHER (1) what brain area? (the location of the cell bodies) TO (2) which part of the spinal cord?

 

superior colliculus cervical spinal cord

 

10. In the midbrain and in the medulla, there are cell bodies for descending motor pathways that terminate in the gray matter of the spinal cord. Give ONE of the MEDULLA locations.

 

vestibular nuclei and reticular formation

 

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. “The thalamus is a ‘relay station’ for incoming sensory information and for outgoing motor control.” ANSWER EITHER (1) The thalamus receives its motor control information from where? OR (2) It sends its output to where?

 

putamen (internal segment) or deep cerebellar nuclei, motor cortex

 

13. According to a block diagram, excitations and inhibitions are enhanced or diminished in quite a few areas. Which is the primary (first) alteration in Parkinson’s disease?

 

duh, dopaminergic input from the substantia nigra to the caudate and putamen

 

14. What do we mean by “genetic anticipation” for the triplet repeat diseases?

 

they can get worse from generation to generation, more triplet repeats

 

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

 

granule cell

 

16. The frontal eye field in the cerebral cortex connects to the parapontine reticular formation directly and indirectly, making a synapse in (where?) along the way.

 

superior colliculus

 

17. What is needed for retinoic acid to bind its response element?

 

retinoic acid receptor

 

18. What is the enzymatic activity of the receptor for bride of sevenless? (Hint, same as for FGF)

 

phosphorylates tyrosine residues (kinase activity)

 

19. Why was it so politically controversial to use embryonic stem cells in human therapy?

 

embryos must be created and destroyed

 

20. The segment polarity gene wingless is not called a “maternal gene.” ANSWER EITHER (1) Why not? OR (2) What is it called instead?

 

the mRNA is made in the embryo, a zygotic gene

 

21. What do you call the cells excluded from the neural tube that eventually become part of the peripheral nervous system?

 

neural crest

 

22. ANSWER EITHER (1) Leukocyte inducing factor (LIF) vs FGF2 determines the neural crest precursor to become what vs what? OR (2) NGF vs CNTF turns a sympathetic progenitor into what vs what?

 

sensory vs autonomic, cholinergic vs adrenergic

 

23. 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

 

24. “Postmitotic neuroblast.” Add detail concerning the exit of the cell cycle.

 

exit at G1

 

25. Frogs flip out your tongues in the wrong direction after Sperry’s inversion of the eye (followed by regeneration). What did Jacobson and Hunt find when the eye was rotated before Harrison stage 28?

 

eye connects appropriately, then anterior-posterior is laid down first, then dorsal-ventral

 

26. 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

 

27. 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

 

28. Removing or adding a supernumerary limb bud speaks to a general mechanism to regulate the number of spinal motor neurons. How is this number regulated?

 

too many precursors, apoptosis prunes numbers

 

29. Before memories are “solidified” in molecular and structural changes at synapses, ANSWER EITHER (1) How (presumably) do you temporarily “hold that thought?” OR (2) Who proposed that idea?

 

with an electrical reverberating loop, Hebb

 

30. A spinal motor neuron was shown in a textbook figure as connecting to several muscle fibers. In what way was this a useful model of “learning?”

 

in terms of modification or plasticity of circuits, early connections are made to multiple cells, then there is a sorting out as motor neurons compete to monopolize the end plate connection

 

31. The magnitude of Aplysia’s gill contraction gets small by the time the siphon was touched for the 13th time, according to the work of Nobel Prize winner Eric Kandel. What is this simple form of learning called?

 

habituation

 

32. Why does it make sense that protein kinase A was found to be involved in long term sensitization?

 

removal of the inhibitory subunits with the ubiquitin pathway leads to long term activation of the catalytic subunits

 

33. A train of stimuli to one Schaffer collateral in the hippocampus leads to a larger EPSP in the CA1 pyramidal cell while the synaptic efficiency is the same for a control Schaffer collateral’s connection. What simple model of learning, first proposed in the landmark 1973 Bliss and Lomo paper, is this?

 

long-term potentiation

 

34. Draw or describe the cancel the line task for a patient with hemispatial (contralateral) neglect syndrome.

 

a page full of little lines is turned to x’s but only on one side

 

35. What is wrong when there is a defect in the FOXP1 transcription factor?

 

dyspraxia in humans (cannot learn speech), song in zebra finch, ultrasonic cries for mother in mice

 

36. 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

 

37. Chimpanzees cannot speak. Argue that this does not mean they cannot communicate by language.

 

research has shown they can learn sign language and other communication tricks that bypass speech

 

38. Why do they call REM sleep “paradoxical sleep?”

 

the EEG looks like the awake state

 

39. What neurotransmitter is sent down to the spinal motor neuron from the medulla to mediate the atonia of REM sleep?

 

glycine

 

40. During the work week, your rhythm is entrained by light and other cues, and it is 24 hours. Give one of the expressions describing your rhythm if the zeitgeber is removed.

 

you are free-running, your biological clock is endogenous, your rhythm is about a day (circadian), your rhythm is longer than 24 hours

 

41. Why would you inject black India ink under the skin on a sparrow’s head to study biological rhythms?

 

to test for and control for light reaching the pineal

 

42. Explain how the eyes of mice that do not have rods or cones can still be involved in entrainment to a light-dark cycle.

 

melanopsin in ganglion cells is the photoreceptor pigment

 

43. “Cryptochrome is a blue sensitive pigment…” Say something about its importance.

 

it is involved in Drosophila circadian rhythms, carotenoid deprivation and action spectra suggest that rhodopsin is not the circadian photoreceptor and cryptochrome is implied, CRY binds to TIMELESS to regulate transcription of certain genes including CRY’s gene

 

44. 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

 

45. You put a rat on a diet and it loses 20% of its body weight because you learned that there are health benefits to dietary restriction. You have the bright idea to revisit the classic hypothalamic lesion experiments that implied, casually stated, that the brain had a hunger center and a satiety center. You discover that one of these lesions no longer caused the rat to change its weight. What is the name of this location?

 

lateral hypothalamus

 

46. What might elicit a symmetric smile in a subject who, when asked to smile, gives an asymmetric smile because of neurological damage?

 

a response to humor

 

47. There are two enzymes that convert testosterone into important hormones. Five alpha reductase forms DHT. ANSWER EITHER (1) What is the other enzyme? OR (2) What is its hormone product?

 

aromatase, 17 beta estradiol

 

48. What prevailing school of thought made Dr. Money think he could get away with turning the boy with the botched circumcision into a girl?

 

nurture more important than nature – gender identity is based more on upbringing than chromosomal make-up

 

49. Where, if at all, does estradiol bind in the rat brain?

 

all over the place, especially hypothalamus (obviously)

 

50. Congenital adrenal hyperplasia ANSWER EITHER (1) Why would that be expected to affect sexual dimorphism? OR (2) What is odd about people who have it?

 

there are androgens coming from the adrenal cortex, females may be slightly male in behavior or in development of genitals

 

51. Why, compared with abnormal numbers of autosomes, is there a high incidence of XXY, XYY, and XO?

 

there are virtually no genes on the Y and all X’s except for one are inactivated in each cell

 

52. “The default pathway is for female development.” Name a chemical directing development away from this default pathway.

 

testosterone, MIH, TDF (product of sry)

 

53. On what basis is it claimed that the act of copulation is costly to a male fruit fly?

 

those who have not mated live longer

 

54. Female moths put out a sex pheromone that attracts males. By contrast, how do the chemical signals of the female fruit fly affect the male?

 

odors on courted or mated females inhibit male courtship

 

55. Some researchers have used mating in fruit flies to study learning. How is it shown, in mating studies, males can learn?

 

they are less likely to court if they have been rejected in previous attempts

 

56. Subject HM, studied by Brenda Milner, could learn a mirror drawing task. Does that mean he is cured?

 

no, procedural memory may be present, but declarative is gone

 

57. Oh sure, a rat with an intact hippocampus can learn the radial 8-arm maze task. But why do they call it “working memory?”

 

each time, the rat remembers what arms it has already visited

 

58. That radial 8-arm maze was not in your textbook. What was the textbook example, and the figure I showed, that got at working memory in the rat?

 

learning to find an underwater platform in a swimming tub

 

59. How did there come to be fragments of amyloid precursor protein, the fragments that form plaques?

 

enzymes called secretases chop away at APP

 

60. Light is absorbed in human rods and cones by a protein bound to a derivative of beta carotene. What is the name of the similar visual pigment in the fruit fly?

 

rhodopsin (product of the ninaE gene), same name as for the human

 

61. In the vertebrate rod, a cyclic nucleotide gated channel mediates the hyperpolarization response to light. What is the channel in the fruit fly microvillus?

 

trp

 

62. 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

 

63. “The human lens absorbs about 4 log units of light at 350 nm.” How did Prof. Stark and Scott Griswold, his undergraduate premedical student, determine this noninvasively?

 

compare spectral sensitivities of subjects with vs without a lens

 

64. Why did “they” decide to put lutein into vitamin pills?

 

macular pigments are thought to protect foveal cones from blue light induced damage, and macular pigments are composed of lutein and zeaxanthin

 

65. Prof. Stark (and you, he hopes) are convinced that human behavior is not predetermined. How did Nobelist Roger Sperry contribute to this conviction?

 

althoughmaterialistic 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.