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The Stimulus • Describe the Physical Properties of Light

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The Stimulus • Describe the Physical Properties of Light Vision About you • What is it about the visual system that interests you? The Stimulus • Describe the physical properties of light o ‘Retina’ slides 1 or 2 will be helpful • How do the physical dimensions of light relate to what is perceived (discuss psycho vs. physics, models vs. representations)? Anatomy • Draw and label the 6 subdivisions of the human CNS o See ‘Why Brains Are Ugly’ slide 8 • Draw and label the anatomy of the human eye o See ‘Retina’ slides 4 or 6 for examples • Draw and label the anatomy of the human retina – include distribution of rods and cones o See ‘Retina’ slides 10, 11, 14, 16 for examples • Draw and label the visual pathways from retina to midbrain and from retina to thalamus to cortex o See ‘Beyond the Retina’ slides 3, 6, and 7 • Diagram and label a ‘hypercolumn’ o See ‘Beyond the Retina’ slides 12-19 for examples How it works • The design of animal sensory systems often involves trade-offs between detection and identification. How are these trade-offs reflected in the design of the human visual system? • Is the coding of color vision a labeled line or across-fiber system? Explain your answer. • How do photoreceptors transducer light, and how do their functional properties relate to the overall design of the eye? • Explain why visual pathways must cross left-to-right and right-to-left. How does this relate to depth perception? o ‘Beyond the Retina’ slides 4 or 6 will be helpful here • Explain the phenomenon of ‘blindsight’. What type of visual functioning persists in such an individual? • Describe the receptive field properties of retinal ganglion cells and V1 cortical cells; explain how a ‘hypercolumn’ works. • Explain how ocular dominance and orientation columns form during development – describe the effects of experience on their formation. What do these data tell us about the interaction of nature and nurture during human development? Audition About you • What is it about the auditory system that interests you? The Stimulus • Describe the physical properties of sound o See ‘Odditory System’ slides 6-10 • How do the physical dimensions of sound waves relate to perceived sound (discuss psycho vs. physics, models vs. representations)? o See ‘Odditory System’ slides 3 and 4 for psycho vs. physics Anatomy • Draw and label the 6 subdivisions of the human CNS o See ‘Why Brains Are Ugly’ slide 9 • Draw and label the anatomy of the human ear (outer, middle, cochlea) o See ’Odditory System’ slides 21-25 for examples • Draw and label the anatomy of an inner hair cell o See ’Odditory System’ slides 32, 33 • Draw and label neural systems for frequency analysis (cortex) and sound localization (midbrain) o See ’Odditory System’ slides 44-45 (cortex) and 49-51 (midbrain) How it works • The design of animal sensory systems often involves trade-offs between detection and identification. How is this reflected in the design of the human auditory system? • Is coding of sound a labeled line or across-fiber pattern system? Explain your answer. • Beginning with the tympanic membrane, describe the chain of events that lead to the activation of an inner hair cell • Describe sources of amplification in the auditory system, and the specific role played by each • Explain the ‘Place Theory’ of frequency encoding (slide 26). How does this theory relate to Fourier analysis? • If inner hair cells detect single frequencies, how could cells in auditory cortex detect complex sounds? • Describe brain regions for speech in humans – how is human speech impaired if these regions are damaged? • Describe how sound localization might work Skin Senses About you • What is it about the somatosensory system that interests you? The Stimulus • Describe the physical dimensions encoded by the somatosensory system o ‘Skin’ slides 2 • Describe the stimuli encoded by basket cells, Pacinian corpuscles, and nociceptors. Anatomy • Draw and label the 6 subdivisions of the human CNS o See ‘Why Brains Are Ugly’ slide 8 • Draw and label the anatomy of three types of cutaneous receptors (basket cell, Pacinian corpuscle, nociceptor). Then describe relative differences in the density of these three receptor types across different regions of skin (for example, hands vs. arms). o See ‘Skin’ slides 4 (basket cell, pacinian) and 25,26 (nociceptor) • Draw and label two pathways (Lemniscal, Spinothalamic) for somatosensory information from receptor to cortex (include the homunculus) o See ‘Skin’ slides 9, 28, and 30 for examples • Diagram the Spinal Gate Theory of pain o See ‘Skin’ slides 27, 28 for examples How it works • The design of animal sensory systems often involves trade-offs between detection and identification. How is this reflected in the design of the human somatosensory and pain systems? • Generally, what is the relationship between receptive field size, receptive field density, and identification? To take a specific example, how do differences in two-point thresholds (see Slide 16) across the skin surface relate to differences in receptive field size and density? • Describe the series of events that lead to activation of a nociceptor, and how this receptor type plays a role in initiating the healing process. • How do development and experience influence the mapping of different regions of the skin in somatosensory cortex? • Using your diagram of the Spinal Gate Theory, explain how this theory works, and how it relates to the organization of the spinothalamic pathway • Discuss neurotransmitters involved in signaling tissue damage – describe potential mechanisms involved in pain relief and chemical dependence. • Discuss the function of pain. Relate to the conduction velocity (i.e., speed at which action potentials are transmitted) of pain fibers. Taste and Olfaction About you • What is it about the chemical senses that interest you? The Stimulus • What are the functions of the chemical senses? Relate to primary tastes. • How does the physical nature of olfactory and taste stimuli (i.e., a variety of volatile and soluble elements and molecules) relate to perceived smells and tastes? Anatomy • Draw and label the 6 subdivisions of the human CNS o See ‘Why Brains Are Ugly’ slide 8 • Diagram the circuitry from tongue to brain - begin with a taste bud. o See ‘Taste and Olfaction’ slides 7-9 and 15 • Diagram the circuitry from olfactory receptors into the olfactory bulb o See ‘Taste and Olfaction’ slides 22, 23, 25 • Diagram the circuitry from olfactory bulb into telencephalon. Include main and accessory olfactory systems. o See ‘Taste and Olfaction’ slides 29-30 How it works • Explain, in terms of what cells need, why it is that the four taste primaries are sour, bitter, salty, sweet. Why is ‘fat’ not on the list of taste primaries, yet still such a common ingredient in our food? Why are detection thresholds lowest for bitter and sour? • Our taste system appears to be largely ‘hardwired’ whereas our olfactory system seems exquisitely open and sensitive to experience. Present evidence supporting these observations and then discuss why taste and smell should be set up this way. • An unusual feature of the chemical senses is the emotional or ‘hedonic’ evaluation that accompanies sensory experience. How is this reflected in the design of chemosensory systems? • Discuss receptor transduction mechanisms for taste and smell • The ‘glomeruli’ of the olfactory bulb are a rather striking anatomical feature. Discuss the functional significance of glomeruli for detection (i.e., thresholds) and coding of olfactory stimuli. • What are ‘pheromones’? On what sensory system do they work? Discuss their role in animal and human behavior. .
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