PSYCH 2220 Perception Lecture 5

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

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

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

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

Structure and organization of the cortex

Pinwheels in the cortex

Visualizing orientation columns in the cortex (Using radioactive deoxyglucose)

Ocular dominance bands over the cortex

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

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

...from a cell in the Inferotemporal cortex 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

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

An example of distributed coding

SPATIAL VISION

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

Just low frequencies all frequencies

invisible Threshold contrast visible Spatial Frequency

Photopic Threshold contrast Scotopic Spatial Frequency