Perception of Visual Stimuli: Channels, Adaptation, and Cortical Organization

1. PSYCH 2220 Perception Lecture 5

2. Keywords for lecture 4 Lateral geniculate nucleus, layers, magnocellular, parvocellular, magnification factor, simple cells, complex cells, hypercomplex cells, Hubel and Wiesel cortical cells tuned for orientation, binocular, tuned for width-of-bars, movement, direction, tilt after effect, adaptation, channel coding

5. Response before adaptation for each channel... .. Is reduced depending on each channel’s adaptation. The peak of the extrapolated curve… .. Is thus shifted. Hypothetical channels Amount of adaptation

6. Response before adaptation for each channel... .. Is reduced depending on each channel’s adaptation. The peak of the extrapolated curve… .. Is thus shifted. Hypothetical channels Amount of adaptation

7. Response before adaptation for each channel... .. Is reduced depending on each channel’s adaptation. The peak of the extrapolated curve… .. Is thus shifted. Hypothetical channels Amount of adaptation

8. Structure and organization of the cortex

11. Pinwheels in the cortex

12. Visualizing orientation columns in the cortex (Using radioactive deoxyglucose)

13. Ocular dominance bands over the cortex

15. What happens beyond the hypercomplex cells? Grandmother cells heirarchy prosopagnosia face cells; hand cells anatomy

17. transient cells magnocellular layers of LGN parvocellular layers of LGN sustained cells

18. Stimuli used to investigate processing of cells in the inferotemporal region. The image of the monkey’s hand elicited the largest response…. ...from a cell in the Inferotemporal cortex

19. A face cell…. ...from the Inferotemporal cortex

25. An example of distributed coding

28. SPATIAL VISION

29. Fourier’s theorem: “any complex curve can be mathematical described as the sum of a series of sine waves”

34. Just low frequencies all frequencies

39. invisible Threshold contrast visible Spatial Frequency

40. Photopic Threshold contrast Scotopic Spatial Frequency