1. PSYCH 2220 Sensation and Perception (I) Lecture 2

2. electromagnetic spectrum, (pit viper), mechanical energy, chemical energy, stages of vision, (i) eye movements, (ii) focus, (iii) light regulation, pupil, pin-hole camera, refraction, focus, cornea, lens, accommodation, myopia, hyperopia, astigmatism, presbyopia Keywords for lecture 1

3. Eye movements Point eyes to right place Accommodation focus Pupils Light Adaptation Adjust for the light level Transduction Convert light energy to activity in cells

10. Photo taken through a LARGE aperture shallow depth of field (only one distance is in focus)

11. Photo taken through a SMALL aperture long depth of field (lots of distances are in focus)

15. AIR LIVING WATER LIVING

18. 1 put on a mask that keeps air in front of cornea 2 rely on a STRONG lens that can change from air-living to water living eg: otter 3 Have a FLAT cornea (to remove its influence) and then use a WATER-LIVING style lens eg. Penguin, flying fish 4 Have two pairs of eyes - one for each environment eg. Four-eyed fish 5 Use a WATER-LIVING style lens in the water and bi-pass the cornea by using a PIN HOLE pupil on land eg. seal DIVING ANIMALS Air Type Water Type

19. 1. Diving mask

20. The Otter - who can change her eye from..... … Air Type….Water Type … to…. 2. strong

21. 3. Flat cornea + fish-type lens

22. Four-eyed fish 4. Four eyes (!)

24. 5. Pin hole on land; fish-type in water

25. Human using the seal solution

26. Antony van Leeuwenhoek (1632-1723)

27. Leeuwenhoek’s Microscope

28. membrane cytoplasm nucleus extra-cellular fluid Potassium K + (Latin Kalium) Na + K+K+ Sodium Na + (Latin Natrium)

29. NERVE CELL synapse neurotransmitters voltage dependent sodium channels ONE WAY

30. ACTION POTENTIAL

31. THE CELL CONCEPT KEYWORDS: Cell, membrane, cytoplasm, nucleus, extracellular fluid ions, sodium, potassium, channels electrode, voltmeter, microelectrode, resting potential millivolt (1/1000 volt) NERVE CELLS sodium channels, action potential axons, synapse, neurotransmitter, millisecond

33. VIEWER SUBJECT Half-silvered mirror How an OPHTHALMOSCOPE works

34. Fovea Optic Disc

35. RETINAL PROPERTYPERCEPTION 1 Image upside down >>>>> seen right way up 2 image is very small >>>>> world seen actual size 3 image on a curved surface >>>>> no curve seen 4 TWO retinas >>>>> only ONE world seen 5 blood-vessel tree >>>>> no tree seen!!!

37. RETINAL PROPERTYPERCEPTION 1 Image upside down >>>>> seen right way up 2 image is very small >>>>> world seen actual size 3 image on a curved surface >>>>> no curve seen 4 TWO retinas >>>>> only ONE world seen 5 blood-vessel tree >>>>> no tree seen!!! 6 BLIND SPOT (where the nerve comes in ) has no receptors >>>>> no hole seen! 7 only the central part of the no difference in retina is very sensitive >>>>> clarity between vision in different parts of the field

40. Filling in

41. Visual memory test: what letters are on the ‘4’ key?

43. So: visual input is poor visual memory is poor therefore vision is poor! We are almost blind!!

44. Sometimes: we see what is not there do not see what is there (Do we ever see what IS there?! There might be more to this perception thing than meets the eye..)

45. Adaptation

47. This one appears brighter... Under PHOTOPIC CONDITIONS.. than this one. but under SCOTOPIC CONDITIONS This one appears dimmer..... than this one.

48. Structure of eye and retina

53. cone Rod

54. RECEPTIVE FIELD: the area in which energy will have an effect VISUAL RECEPTIVE FIELD: the area in the outside world where light will have an effect

57. The foveal pit

58. Different pigments Different shape Different distribution Different sensitivity

60. RETINAL GANGLION CELLS