Sensory Processing II

Transcription

1 10 th or 11 th Lecture Fri/Mon 06/09 Feb 2009 Vertebrate Physiology ECOL 437 (MCB/VetSci 437) Univ. of Arizona, spring 2009 Kevin Bonine & Kevin Oh Sensory Processing II Chapter 13 1

2 Housekeeping, Fri 06 February 2009 Readings Today: Chapter 13 Mon 09 Feb: Ch 13 Wed 11 Feb: Ch14 LAB Wed 11 Feb: experiment and review Fri 13 Feb: Exam 1 Fri 13 Feb = Exam 1 Lab discussion leaders: 25 Feb 1pm Jesse, Hang 3pm Alex, Max Lab discussion leaders: 18 Feb 1pm Maggie, Shandy 3pm Shawn, Kendall 2

3 sponsored by EEB, Poetry Center, the UA Bookstore & others at UA art by Holly Randall3

4 Sensory Systems (con t) Ch13 in your text 4

5 External Chemoreception (Taste and Smell) -Taste ~ direct contact -Smell ~ distant signal source -Chemoreception very sensitive -Bombyx moth antenna example: Male responds to female pheromone at low [ ] of 1 molecule in 10 17! 5

6 Taste Chemoreception -Taste Usually oral cavity Some fish fins! 4-5 qualities: 1. Salt 2. Sour 3. Sweet 4. Bitter 5. Umami ( savory or meaty ) Salty Sour Sweet Differing Receptor Properties 7-17 Randall et al

7 Taste - microvilli - basal cells give rise to new receptor cells every 10 days 7-16 Randall et al

8 10-14 Silverthorn 2001 human 8

9 10-15 Silverthorn

10 Taste Facial nerve Outer tongue -Quasi Labelled lines - multiple receptor types/neuron Inner tongue 10

11 Smell 11

12 Smell/ Olfaction -1 Nasal Cavity -turbinates ( s.a.) -2 Vomeronasal organ -usually conspecific communication 7-19 Randall et al Randall et al

13 Smell/ Olfaction -Nasal and Vomeronasal: -Epithelial tissue origin -Cilia or Microvilli covered in mucus -Receptor proteins with 7-transmembrane helices -Coupled to G-protein cascade 7-21 Randall et al

14 Smell/ Olfaction - Nasal and Vomeronasal: -Thousands of receptor proteins (general & special) -but different for nasal and vomeronasal -Receptor cells contain axons - Glomeruli in olfactory bulb/accessory olfactory bulb 7-21 Randall et al

15 Olfactory bulb (info processing in brain) Glomeruli (similar odor receptor synapses) axons Sensory neurons (~ odor specific) Mucus from epithelial glands dendrites 15

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17 Olfactory Neurons In humans, 10 7 olfactory receptor neurons In dogs, 2x10 8 Human auditory nerve: 10 4 Human optic nerve:

18 Study: Strippers Make More in Tips When Most 'Fertile' Thursday, October 04, 2007 A new study from the University of New Mexico found that, on average, strippers make the most money in tips during the most fertile days of their monthly cycles, Psychology Today reports. Researchers also found that women who take the birth control pill make less in tips overall than women who do not take the pill, $37 an hour versus $53 an hour, respectively. For their research, psychologist Geoffrey Miller and colleagues visited local gentlemen's clubs and counted tips made on lap dances. Dancers made about $70 an hour during their peak period of fertility, versus about $35 while menstruating and $50 in between. Researchers attributed the fluctuation in tips to the changes in body odor, waist-to-hip ratio and facial features that occur throughout a woman's cycle. 18

19 What is a FOVEA? Explain how the fovea compares among mammalian vision star-nose touch and bat hearing How is a fovea observable in the brain? 19

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21 Vision 7-34 Randall et al FOCUS - light is focused by lens (and cornea) to create an image on the retina - refraction by cornea (85%) and by lens (15%) -alter focal length by altering shape and curvature of lens (zonular fibers and ciliary muscle sphincter ) - binocular convergence (both eyes on same part of retina) LIGHT INTENSITY - pupil for variable aperture via iris and radial muscle 21

22 7-37 Randall et al

23 10-27 Silverthorn

24 distant close Out of focus Silverthorn 2001 Humans lose ability to make lens round as we age. 24

25 Vision ~ANATOMY - sclera white tough outer layer - choroid lots of blood vessels - pigment layer with photoreceptors - fovea where highest acuity and highest # cones -(visual streak?) TRANSDUCTION - photoreceptors (rods and cones) -Transduce photons (light) into electrical signal - rhodopsins (visual pigments) opsin (7-transmembrane lipoprotein) plus retinal (absorbs photon) 25

26 Vision Receptor Cells Rods and Cones -Dim light, low resolution -Bright light, high resolution 7-38 Randall et al

27 Blind Spot Silverthorn 2001 Rods and Cones 27

28 Rhodopsins (visual pigments) -located in stacked lamellae Membranes hyperpolarize in response to light Na + dark current 7-39 Randall et al When light hits, the Na + current into the cell is stopped and membrane hyperpolarizes stopping release of NT 28

29 Bleaching of retinal photoreceptors Expectation after 15 seconds? Photoreceptors called cones respond to particular wavelengths of light. Their response involves bleaching of their responsive pigment, so that for some seconds they are unable to respond again. 29

30 Bleaching of retinal photoreceptors Expectation after 15 seconds? Photoreceptors called cones respond to particular wavelengths of light. Their response involves bleaching of their responsive pigment, so that for some seconds they are unable to respond again. 30

31 Bleaching of retinal photoreceptors Expectation after 15 seconds? Photoreceptors called cones respond to particular wavelengths of light. Their response involves bleaching of their responsive pigment, so that for some seconds they are unable to respond again. 31

32 Rod and Cone details Sensitivity vs. Acuity Action spectrum (where absorb light) Silverthorn (e.g., humans, fish) 5 (e.g,. birds) different photopigments (opsin varies, retinal ~same) Porphyropsins (different retinal) seem better than rhodopsins in freshwater 32

33 Rhodopsin 33

34 Rhodopsin mechanism: cis-->trans isomerization of retinal molecule activated 7-43 Randall et al Changes conformation of opsin molecule and therefore initiates transduction 34

35 7-44 Randall et al Activated retinal changes conformation of opsin molecule (opsin and retinal separate) and initiates transduction G-protein amplification Need to reconstitute the rhodopsin 7-45 Randall et al (night blindness) 35

36 Physiology Players Theatre -2 competing casts -Judge(s) -accuracy -enthusiasm 7-49 Randall et al Red vs. Green opsin Actors: 1. Photon 4. Transducin 7&8. Ion channel 2. Retinal 5. PDE 9. Cation (Na + ) 3. Opsin 6. cgmp Act I Photon enters stage right. Other players assembled within or near membrane. photo transduction... Dark current reduced as curtain closes. 36

37 Photon Transduced Now what? Other Cells Horizontal Bipolar Amacrine Ganglion Hill et al. 2004, Fig

38 Horizontal Cells for lateral communication Bipolar Cells transfer information from Photoreceptors to Amacrine and Ganglia Cells Amacrine Cells act like a second layer of lateral communication and integration Ganglion Cell axons form the optic nerve and communicate retina information to CNS Rods and Cones synapse on BOTH Horizontal Cells & Bipolar Cells Lots of information processing before leave eye! 38

39 On-Center vs. Off-Center Hill et al. 2004, Fig Center vs. Surround 39

40 Lateral (info from surround) Straight-through (info from center) Combination allows for crisp edges in visual images. Hill et al. 2004, Fig

41 Enhancing Receptor Sensitivity Lateral Inhibition 7-14 Randall et al e.g., improve touch sensitivity and visual acuity (edges especially) 41

42 Lateral Straight-through Hill et al. 2004, Fig

43 Receptive Field of Complex Cell in Visual Cortex Hill et al. 2004, Fig Individual Ganglia are part of many Receptive Fields 43

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