PSYC10003 Lecture Notes - Lecture 15: Spatial Frequency, Photon, Retina
13 Jun 2018
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10th Apr ‘18
MBB1 Week 6; Lecture 15 Notes
Receptive fields
visual receptive field
-describes the properties of the neurons
-construction of image
-after photoreceptors = turns into numbers = and the brain turns it into an image
-concept of receptive field
-abstract concept describing sensitivity of sensory neurone
-cone: area of space over where it will absorb photons within specific range of wavelengths
-sensitivity range & area over which cone will respond = receptive field
-cone receptive field: base of cone, a circle
-has specific photopigment: certain type of photon which it will absorb
-2 adjacent photons:
-they both have equal but opposite responses to the same event
-creates a change detector: mechanism that will only respond to change over area of
sensitivity
-only elicits change when theres a difference in magnitude between the two photons
-central area of interest = with a light stimulus
-light stimuli in the centre causes A to have a small output
-when light increases in intensity/size, output increases
-when light covers whole centre = big output
-but if the light goes over the centre interest, to inhibitory photons, output decreases
-A’s output increases and then decreases as events increase
-he’s selective, only like certain things
-lighten A’s centre, darken the surroundings = maximal output
-vice versa = minimal output
-A responds best to things that create the largest change between centre & surroundings
-retina (look at lecture slides)
-colour opponent receptive field
-M-L receptive field: - - in the middle, ++ outside
-L-M receptive field, - - outside, ++++ in the middle
-B-Y = (M+L)
-amplitude/contrast
-spatial frequency
-spatial phase
find more resources at oneclass.com
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Document Summary
After photoreceptors = turns into numbers = and the brain turns it into an image. Abstract concept describing sensitivity of sensory neurone. Cone: area of space over where it will absorb photons within specific range of wavelengths. Sensitivity range & area over which cone will respond = receptive field. Cone receptive field: base of cone, a circle. Has specific photopigment: certain type of photon which it will absorb. They both have equal but opposite responses to the same event. Creates a change detector: mechanism that will only respond to change over area of sensitivity. Only elicits change when theres a difference in magnitude between the two photons. Central area of interest = with a light stimulus. Light stimuli in the centre causes a to have a small output. When light increases in intensity/size, output increases. When light covers whole centre = big output. But if the light goes over the centre interest, to inhibitory photons, output decreases.
