REVIEW QUESTIONS AND SAMPLE MIDTERM QUESTIONS FOR THE MIDTERM EXAM

Transcription

1 REVIEW QUESTIONS AND SAMPLE MIDTERM QUESTIONS FOR THE MIDTERM EXAM REVIEW QUESTIONS Chapter 1 / Lecture 1 1. Diagram a neuron and label its components. In what ways are neurons specialized for communication? How can these specializations be used to distinguish neurons from other types of cells? 2. What is the reticular theory of the nervous system, and how does it differ from the neuron doctrine? 3. What are the main types of glial cells, and what is the main function of each? Glia outnumber neurons in the brain, yet neurons tend to be the focus of studies. Why? 4. Give one example of an organizational characteristic of the brain that is conserved among vertebrates, an example of an organizational characteristic that is conserved among vertebrates and invertebrates, and one that is different between vertebrates and invertebrates. 5. Explain what is known about the relationship between gene sequence complexity and neural complexity. 6. What manipulations does optogenetics provide, how do they work, and what is one advantage and one disadvantage of optogenetic manipulations? 7. What are the major characteristics that distinguish between the central nervous system (CNS) and the peripheral nervous system (PNS)? 8. Review anatomical structures in boldface in the Appendix; pay special attention to the cranial nerves and the mjor features of the blood supply to the brain. Chapter 9 / Lecture 2 1. What are the relative functional differences between phasic (rapidly adapting) versus tonic (slowly adapting) receptors, and what kind of information does each of these receptor classes supply to the brain? 2. What is proprioception? Name three kinds of proprioceptors. 3. What is a somatosensory receptive field of a neuron? Be able to describe how this is measured; are the techniques different for measuring this in the peripheral or central nervous system?

2 4. Where are the gracile and cuneate nuclei? What is the equivalent of the dorsal column nuclei for somatosensory input from the face? 5. Where is the primary somatic sensory cortex (SI)? Are there differences between the four Brodmann s areas that comprise SI? 6. What are some afferent and efferent connections of SI? 7. Compare the dorsal column (medial lemniscal) and spinothalamic (anterolateral) pathways with respect to anatomy and sensory modality. For each pathway, where are the cell bodies and axon terminals of the first-, second- and third-order neurons? Where does each pathway decussate? Is the left side of the body represented in the right or left SI cortex? 8. What are barrel fields in the somatosensory cortex of rodents? What do neurophysiological stimulation studies tell us about the role of single pyramidal cells vs. local cell populations in conscious somatosensory perception? 9. Describe one aspect of the somatosensory system that does not appear to be very plastic, and one that does appear to be plastic. Back this up with a description of the relevant experiments. Chapter 10 / Lecture 3 1. What is the evidence that nociception is mediated by specific nociceptors rather than by strongly stimulated tactile receptors or warmth receptors? 2. What are hyperalgesia and allodynia? Summarize the contributions of peripheral and central sensitization to each of these phenomena. 3. Due to a spinal injury, a patient has lost pain and temperature sensation on the left half of his body from the waist down. Where is his injury? Where would you expect loss of tactile sensation in this patient? 4. Give an example of referred pain and offer a possible explanation. 5. What is the major pathway for visceral pain? 6. Describe the neural pathway for affective motivational aspects of pain. Describe the kind of evidence that shows whether or not it is involved in placebo effects and empathic pain. 7. What is the gate control theory of pain, and does it have any practical applications? 8. Describe the anatomical and physiological basis for headache pain being affected by light exposure.

3 Chapter 11 / Lectures 4,5 1. How do rods and cones differ, and why do you have both instead of just one type of photoreceptor? 2. Do you have more rods or cones in your retina? In your fovea? What accounts for the fact that your rods do not contribute to vision in daylight? 3. Draw a simplified diagram of the retina, label the five types of retinal neurons, and draw the path that light follows before it stimulates a photoreceptor. Which layer is the outer nuclear layer? 4. Is the retina part of the central or peripheral nervous system? Explain. 5. Vertebrate rod and cone function appears to be counter-intuitive, because they are depolarized ( 40 mv) in darkness and are hyperpolarized by light stimuli. What components of photoreceptors account for this? 6. What is the evidence that color vision is trichromatic? What does color opponency mean with respect to receptive fields of parvocellular retinal ganaglion cells? 7. What features distinguish off-center and on-center retinal ganglion cells? Explain how this receptive field organization is useful in detecting luminance contrast and changes in light intensity. 8. List the key steps in phototransduction in a rod, from absorption of a photon to decreased cgmp concentration and closure of ion channels. 9. Why is light adaptation in the retina so important, and what kind of circuitry elements does it involve? 10. Describe one role that horizontal cells play in mediating visual percepts. Chapter 12 / Lectures 6,7 1. What percentage of the axons in the human optic nerve cross at the optic chiasm? 2. Draw a sketch of the primary visual pathway up to the primary visual cortex. 3. The retina sends information to the dorsal lateral geniculate nucleus (dlgn) for pattern vision. Name at least three other targets of retinal ganglion cells and indicate what each pathway is specialized for. 4. Describe what an intrinsically photosensitive retinal ganglion cell is, how it connects

4 to the brain, and the physiological roles it plays. 5. If your right visual cortex stopped functioning, what part of your visual field would be lost? 6. What part of the retina has the largest proportional representation in the primary visual cortex? 7. Is the world mapped upside down on the retina? On V1? 8. Explain how Hubel and Wiesel mapped visual receptive fields of simple cells in the primary visual cortex. How do receptive field characteristics of neurons in V1 compare with those in the dlgn? 9. What is optical imaging, and what are its technical limitations? Describe its role in vision research, and the organizational features it has helped to describe. 10. Are binocular neurons found in the LGN? In layer IV of primary visual cortex? Where does input from both eyes first converge? 11. What are ocular dominance columns and orientation columns? Are their boundaries completely independent of each other? 12. What lines of evidence suggest that the magnocellular and parvocellular streams are two parallel anatomical pathways with functionally distinct characteristics? 13. Describe what the Sprague Effect is, and its significance for understanding conscious visual perception and for neuropsychological work in general. 14. Describe what is known about the role of extrastriate thalamic projections in blindsight, and how this is known. Chapter 13 / Lectures 8, 9, What perceptual qualities are based on frequency and amplitude of sound waves? Describe the role that the phases of sound components may play in auditory perception. 2. What is the audible frequency range of humans (in Hertz)? Does it change with age? What is the approximate range of frequencies that is most important for comprehending human speech sounds? 3. Describe what tonotopy is and how it is a result of the structure and function of the cochlea and the substructures found within it. 4. List the steps in stimulus transduction, from the physical sound stimulus to the

5 generation of electrical signals within inner hair cells. Indicate which steps take place in the external, middle, and inner ear, and how these events differ for the compression and rarefaction phases of a sound wave. 5. What types of fibers are carried in the auditory nerve, what structures of the inner ear are these associated with, and how many hair cells are associated with one of each type of fiber? 6. How does a cochlear implant work? How does cochlear-implanted hearing differ from normal hearing? 7. There are more outer hair cells than inner hair cells. What are the structural differences between inner and outer hair cells and the way they are arranged on the basilar membrane, and what do the outer hair cells do? 8. Describe both mechanical and electrical specializations that are involved in producing tonotopy on the basilar membrane. 9. Describe the travelling wave, how its characteristics change between a living and dead organism, what the upward spread of excitation as a sound gets louder refers to, and the mechanism that produces it. 10. What types of neural spike patterns do peripheral and central portions of the auditory system use to code sound frequency? 11. Where does the auditory nerve project? What brain regions does the information travelling in the auditory nerve that comes from the brain and goes to the cochlea originate in? 12. What is a distortion product? What structures on outer hair cells are critical for the generation of distortion products, and how do we know this? 13. What is the basic auditory pathway from the cochlea to the forebrain? Do higher auditory brain structures influence the activity of lower ones directly, and how do they do this? In what ways is the human auditory system organized like that of other primates? 14. What is pitch? Describe why pitch perception is not the same thing as frequency perception, and whether any neural correlates of pitch have been found in auditory cortical areas. 15. What is a critical band, and what relationship does it play to so-called resolved and unresolved simultaneous tones? 16. What major transformation in auditory neural responses takes place after the level of the midbrain?

6 17. Compare the strategies for sound localization used by ITD neurons in the MSO versus IID neurons in the LSO/MNTB. What aspects of neural circuit function shape the responsiveness of single neurons in these areas? 18. What is a delay line with respect to auditory sound localization? What anatomical feature determines physically-possible delay line values? Describe behavioral and neural evidence demonstrating that humans can only use delay line information in the normal range of values. 19. Describe some ideas about structural and functional asymmetries in the higher auditory system that scientists at first thought were unique to humans, and the evidence that suggests that these are instead characteristics that are shared with other vertebrates. 20. The primary visual and somatosensory cortices have a topographic map of sensory space. What evidence can you cite to show that information coming through the auditory cortex is important for sound localization? Does this information depend in any way on the functional integrity of supposedly visual brain structures like the superior colliculus? Chapter 14 / Lecture Explain how the semicircular canals are specialized to assess rotational acceleration of the head, while the otolith organs are specialized to detect linear acceleration and static position of the head relative to the gravitational axis. 2. As your head turns horizontally to the left, what happens to activity levels in your left and right vestibular nerve? The imbalance in neural activity would lead to physiological nystagmus, with the slow component in which direction? What purpose would these eye movements serve? A similar imbalance of activity would be obtained by irrigating your left ear with (warm or cold?) water. 3. If you lost your vestibulo-ocular reflex (VOR), what symptoms would you experience? 4. Which cranial nerve serves both vestibular and auditory hair cells? Where does the vestibular nerve project? 5. What purposes do the vestibulo-cervical and vestibulo-spinal reflexes serve? 6. How does vestibular information reach the cortex? 7. Describe the Mauthner cell circuit in fish and its similarity to vestibular reflex circuits. Chapter 15 Lecture Describe the steps in sensory transduction in olfactory neurons.

7 2. What features of the olfactory system make it so sensitive to low concentrations of odorants? 3. What clues are there as to how the olfactory system might recognize odors? 4. How does olfactory information reach brain regions that perceive and interpret odors? What is the primary olfactory cortex? 5. What features of the olfactory system distinguish it from other sensory systems? Consider sensory transduction, sensory pathways, stimulus coding, and perception. 6. Why are the receptor cells in olfaction, but not gustation, classified as neurons? 7. Are there primary taste categories? If so, what are they? 8. How does taste information reach the neocortex? What part(s) of the cortex receive input from the taste pathway? 9. List a few similarities and a few differences between olfaction and taste. 10. Are individual odors and tastes recognized by a labeled line strategy or by computing activity from ensembles of neurons? Explain. 11. Describe the trigeminal chemosensory system, its sensitivity relative to smell and taste, and the special subjects one needs to use to study its perceptual function. SAMPLE MIDTERM TEST QUESTIONS: 1. In the human brain, flexion of the spinal cord relative to the long axis of the brain results in ambiguity of directional terms relative to animals that walk on all fours. Which statement best captures this state of affairs? a. In the human brain, the terms superior and dorsal refer to the same direction, while in the spinal cord they do not. b. In the human brain, rostral and caudal are at right angles to dorsal and ventral, while in the spinal cord they are not. c. Anterior vs. posterior always match dorsal vs. ventral in both the human brain and spinal cord. d. Answers a & b e. Answers a & c 2. Which type of sensory fiber would conduct signals fastest? a. b. A type III muscle nerve c. d. A type I muscle nerve e. Answers c & d have the same conduction velocity

8 3. Sensory information from different parts of the body differs in where it first synapses in the spinal cord, and where in the white matter its axon tracts are located. How would sensory information from your feet differ from that of your hands? a. It first synapses in the dorsal root ganglion and travels more laterally b. It first synapses in the thalamus and travels more medially c. It first synapses in the cuneate nucleus and travels more laterally d. It first synapses in the gracile nucleus and travels more medially e. None of the above are true 4. Visceral pain (i.e. from the abdomen) ascends in which sensory pathway? a. The dorsal column-medial lemniscus system b. The anterolateral system c. The trigeminothalamic tract d. The dorsolateral tract of Lissauer 5. Failure of which process in the human eye can lead to glaucoma? a. Phagocytotic removal of stray blood cells and debris from the vitreous humor b. Regulation of the opacity of the cornea or lens c. Drainage of the aqueous humor by cells in the limbus d. Adjustment of pupil size by the iris and ciliary muscles e. Production of aqueous humor by the ciliary processes 6. Suppose your friend gives you a "thumbs up" sign while you are fixating on her face, such that the thumb appears in the right superior portion of your binocular visual field. Where will this image appear on your left and right retina? a. Left retina: nasal, inferior; Right retina: temporal, inferior b. Left retina: nasal, superior; Right retina: temporal, superior c. Left retina: temporal, inferior; Right retina: nasal, inferior d. Left retina: temporal, superior; Right retina: nasal, superior 7. Which of the following statements about the structure and function of vestibular organs is accurate? a. Hair cells in a vestibular canal toward which the head is turning are hyperpolarized, while hair cells in a canal away from which the head is turning are depolarized. b. The utricle is primarily concerned with vertical motion, the saccule is primarily concerned with motion in the horizontal plane c. Angular accelerations will cause an increase or decrease of discharge rate in the associated vestibular canal, followed by a period of constant discharge rate during a constant angular velocity d. All of the above are correct e. None of the above are correct

9 8. The Edinger-Westphal Nucleus is involved in the pupillary light reflex. In which part of the brain is it found? a. Lateral Upper Medulla b. Medial Midbrain c. Lateral Lower Pons d. Medial Caudal Medulla e. Lateral Midbrain