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M.Sc. CNS Visual Perception
Concept of receptive field
Stan GielenDept. of Biophysics
M.Sc. CNS Visual Perception
What is a “receptive field” ?That part in stimulus space that affects the
responses of a neuron:• visual system:
– direction in space , corresponding with a particular retinal area
– frequency range in colour space
• auditory system:– frequency– direction relative to the head
M.Sc. CNS Visual Perception
Retinal organization
M.Sc. CNS Visual Perception
Origin of Centre-Surround organisation
M.Sc. CNS Visual Perception
Receptive field in retina
M.Sc. CNS Visual Perception
Local excitation; global inhibition
M.Sc. CNS Visual Perception
2D spatial receptive field
2
22
2
22
2exp
2exp),(
sc
yxB
yxAyxf
M.Sc. CNS Visual Perception
2D spatial receptive field
2
2
2exp)(
c
xAxf
Spatial frequency k
2
k
2exp)(
22ck
Akf
M.Sc. CNS Visual Perception
2D spatial receptive field
2
22
2
22
2exp
2exp),(
sc
yxB
yxAyxf
freqlog
centre
surround
M.Sc. CNS Visual Perception
Spatial contrast sensitivity
O Centre only
Centre plus surround�
M.Sc. CNS Visual Perception
2D (spatio-)temporal receptive field
)(2
exp)(2
exp);,(2
22
2
22
tthyx
Bthyx
Atyxfsc
t t
h(t)
log temp freq
M.Sc. CNS Visual Perception
2D spatio-temporal receptive fieldeffect of centre-surround on temporal properties
)(2
exp)(2
exp);,(2
22
2
22
tthyx
Bthyx
Atyxfsc
t t
h(t) Stimulation of C + S: Higher sensitivity for high temporal frequencies
M.Sc. CNS Visual Perception
Temporal sensitivity of Center
M.Sc. CNS Visual Perception
Temporal sensitivity of C+S
M.Sc. CNS Visual Perception
Spatial sensitivity of C+S
M.Sc. CNS Visual Perception
Measured and simulated responsesfor cells with linear spatial summation
On center Off center
Data Model
M.Sc. CNS Visual Perception
Cells in Primary visual cortex
M.Sc. CNS Visual Perception
Cortical receptive fields
M.Sc. CNS Visual Perception
2D spatial receptive field of center of cell in visual cortex
2
2
2
2
2exp
2exp),(
ba
yxAyxf
M.Sc. CNS Visual Perception
2D spatial receptive field of center of cell in visual cortex
2
2
2
2
2exp
2exp),(
yx
yxAyxf
2exp
2exp),(
2222yyxx
yx
kkAkkf
M.Sc. CNS Visual Perception
2D spatial receptive field of center of cell in visual cortex
2
2
2
2
2exp
2exp),(
yx
yxAyxf
2exp
2exp),(
2222yyxx
yx
kkAkkf
ky
kx
M.Sc. CNS Visual Perception
2D spatial receptive field of cell in visual cortex
2
2
2
2
2
2
2
2
2exp
2exp
2exp
2exp),(
sysxcycx
yxB
yxAyxf
2exp
2exp
2exp
2exp),(
22222222sysysxsxcycycxcx
yx
kkB
kkAkkf
ky
kx
Surround causes sharpening of receptive field
M.Sc. CNS Visual Perception
Spatial frequencies for testing visual receptive fields
M.Sc. CNS Visual Perception
Visual vs auditory receptive field
M.Sc. CNS Visual Perception
M.Sc. CNS Visual Perception
Receptive field sizes
2
2
20 2exp
2
1),(
xxG
),(2
exp2
1),(),( 022
2
2201 xGxxx
xGx
xG
),(11
2exp
2
11
1),(),( 02
2
22
2
22
2
202
2
2 xGxxx
xGx
xG
Receptive fields form a local “Taylor expansion” of image
M.Sc. CNS Visual Perception
References
• S. Shamma, On the role of space and time in auditory processing, Trends in Cognitive Sciences Vol.5, 340-348 2001
