Review, the visual and oculomotor systems · 2020. 12. 30. · The visual and oculomotor systems Peter H. Schiller, year 2013 Review, the visual and oculomotor systems Basic wiring

The visual and oculomotor systems Peter H. Schiller, year 2013

Review,

the visual and oculomotor systems

1

Basic wiring of the visual system

2

Primates

3

Image removed due to copyright restrictions.

Please see lecture video or Figure 3 from Schiller, Peter H., and Edward J. Tehovnik."Visual prosthesis." Perception 37, no. 10 (2008): 1529.

Retina and LGN

4

sign inverting synapse sign conserving synapse

receptors

pigment epithelium

incoming light

photo-

conesrods

ON OFF ONbipolars

ON OFF

ganglion cells

to CNS

Hcone horizontal

amacrine

AII

IPL

amacrine

AII

OPL

rods

ON OFF ONbipolars

ON OFF

ganglion cells

to CNS

Hcone horizontal

receptors

pigment epithelium

incoming light

photo-

cones

gap junction glycinergic synapse

Bipolar glutamate receptors: ON = mGluR6 OFF = mGluR 1 & 2

5

fovea

6

5

4

3 2 1

periphery4 3 2 1

6 layers 4 layers

midget/parasol ratio: fovea: 8 to 1 periphery: 1 to 1

midget

parasol

fovea periphery

eccentricity

Coronal section of monkey LGN

Figure removed due to copyright restrictions.

6

Please see lecture video or Figure 4A of Schiller, Peter H.,

and Edward J. Tehovnik. "Visual Prosthesis." Perception37, no. 10 (2008): 1529.

Visual cortex

7

8

Central Sulcus

V1

Lunate

V4

LIPSTS

Principalis

Arcuate

MIPMEP

FEF

Image by MIT OpenCourseWare.

123456

1-2 = magno3-6 = parvo

P

M

K2

LGN

V1

Lamina:

interlaminar

K1

Cortical projections from LGN

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Transforms in V1

Orientation Direction Spatial Frequency Binocularity ON/OFF Convergence

Midget/Parasol Convergence

10

11

Original Hubel-Wiesel "Ice-Cube" Model

Left Eye Right Eye

Left Eye Right Eye

Swirl Model

Sub-cortical

Cortical

Radical Model

MidgetParasol

1 m

m


Three models of columnar organization in V1

Striate Cortex Output Cell

Intracortical

Midget ON Midget ON Midget OFFMidget OFF RIGHT EYE

INPUT LEFT EYE

INPUT Parasol ONParasol ON Parasol OFF Parasol OFF

luminance color

orientation spatial frequency

depth motion

12

Extrastriate cortex

13

Central Sulcus

V1

Lunate

V4

LIPSTS

Principalis

Arcuate

MIPMEP

FEF


Major cortical visual areas:

Occipital V1 V2 V3 V4 MT (medial temporal)

Temporal IT (inferotemporal)

Parietal LIP (lateral intraparietal) VIP (ventral intraparietal) MST (medial superior temporal)

Frontal FEF (frontal eye fields)

15

The ON and OFF Channels

16

The receptive fields of three major classes of retinal ganglion cells

OFF

inhibition

ON

inhibition

ON/OFF

inhibition

17

Action potentials discharged by an ON and an OFF retinal ganglion cell


18

Please see lecture video or Figure 2A of Schiller, Peter H., and Edward

J. Tehovnik. "Visual Prosthesis." Perception 37, no. 10 (2008): 1529.

The 2-amino-4-phosphonobutyrate (APB) experiments blocking the ON channel:

1. No effect on center-surround antagonism and on orientation and direction selectivities in V1.

2. Deficit in detecting light increment but not

light decrement.

19

The central conclusion:

The ON and OFF channels have emerged in the course of evolution to enable organisms to process both light incremental and light decremental information rapidly and effectively.

20

The midget and parasol channels

21

MIDGET SYSTEM PARASOL SYSTEM

Neuronal response profile

ON OFF ON OFF

time 22

Projections of the midget and parasol systems

Midget

P

Midget

1V

MT

Mixed

Parasol

w

?

Parasol

LGN M

PARIETAL LOBE TEMPORAL LOBE

2

V4

V2V

23

MTV 4

mild

mild

mild

mild

mild

mild

none none

none none

none none

none

none

none

none

none

none none

none none

none

none

moderate

mild

pronounced

severe none

none

not tested

severe

severe

pronounced

color vision

VISUAL CAPACITY PLGN MLGN

coarse scotopic vision

brightness perception

contrast sensitivity

motion perception

flicker perception

fine

coarse

stereopsis fine

coarse

pattern perception

shape perception

texture perception

fine coarse

severe

severe

severe

severe

severe

severe

severe

mild

mild

none

none

none

none

none

none

none

none

none

none

none

none

none

none

none

moderate

pronounced

fine

choice of "lesser" stimuli

not testedvisual learning

not tested

not tested

not tested

nonesevere

object transformation

INTE

RM

EDIA

TE

BA

SIC

VIS

UA

L FU

NC

TIO

NS

Summary of PLGN and MLGN lesion deficit magnitudes

24

The midget system extends the range of visual processing in the spatial frequency and wavelength range.

The parasol system extends the range of visual processing in the temporal frequency range.

25

H

H

H

H

L

L

L

L

Proc

essi

ng C

apac

itySpatial Frequency

Temporal Frequency

Parasol SystemMidget System


Color vision and adaptation

26

The color circle

27

Saturation

Y

B

RG

Hue


Basic facts and rules of color vision 1. There are three qualities of color: hue, brightness, saturation

2. There is a clear distinction between the physical and psychological attributes of color: wavelength vs. color, luminance vs. brightness.

3. Peak sensitivity of human photoreceptors (in nanometers): S = 420, M = 530, L = 560, Rods = 500

4. Grassman's laws: 1. Every color has a complimentary which when mixed propery yields gray. 2. Mixture of non-complimentary colors yields intermediates.

5. Abney's law: The luminance of a mixture of differently colored lights is equal to the sum of the luminances of the components.

6. Metamers: stimuli producing different distributions of light energy that yield the same color sensations.

28

Response to Different Wavelength Compositions in LGN Blue ON cell Yellow ON cell

90 90

30 40 0

45135

180

225 315

270

50 40 60 80 0

45135

180

225 315

270

Spikes per Second

20 100 6010 20

Green OFF cell Red ON cell 90 90

20 0

45135

180

225 315

270

10 20 30 40 0

45135

180

225 315

270maintained discharge rate

10 5030 40

29

30

400

300

200

100

0-5 -4 -3 -2 -1 0

Dis

char

ge ra

te (s

pike

s/se

c) 0-1-2-3-4-5backgroundlog cd/m2

Test flash (log cd/m2)


Response of a retinal ganglion cell at various background adaptation levels

Basic facts about light adaptation

1. Range of illumination is 10 log units. But reflected light yields only a 20 fold change (expressed as percent contrast).

2. The amount of light the pupil admits into the eye varies over a range of 16 to 1. Therefore the pupil makes only a limited contribution to adaptation.

3. Most of light adaptation takes place in the photoreceptors.

4. Any increase in the rate at which quanta are delivered to the eye results in a proportional decrease in the number of pigment molecules available to

absorb those quanta.

5. Retinal ganglion cells are sensitive to local contrast differences, not absolute levels of illumination.

31

Depth perception

32

Cues used for coding depth in the brain

Oculomotor cues Visual cues

accommodation vergence

Binocular stereopsis

Monocular motion parallax

shading interposition

size perspective

33

Autostereogram


Masayuki Ito, 1970, Chris Tyler, 1990

34

Please see lecture video or the autostereogram from The Magic Eye, Volume I:

A New Way of Looking at the World. Andrews McMeel Publishing, 1993.

MOTION PARALLAX, the eye tracks

object motion

1

2

a

b

1

2

a

b eye movement

The eye tracks the circle, which therefore remains stationary on the fovea

Objects nearer than the one tracked move at greater velocities on the retinal surface than objects further; the further objects actually move in the opposite direction on the retina.

35

37

37

Form perception

39

Three general theories of form perception:

1. Form perception is accomplished by neurons that respond selectively to line segments of different orientations.

2. Form perception is accomplished by spatial mapping of the visual scene onto visual cortex.

3. Form perception is accomplished by virtue of Fourier analysis.

40

Form perception with little information about orientation of line segments


41

Please refer to lecture video.

Cortical layout of neurons activated by disks

disks in one hemifield

42Image by MIT OpenCourseWare.

Cortical layout of neurons activated by disks

disks across midline

43

123456

907

0

-45

-90

-45

0

45

0.250.5

1 2 4 790

45

0

-45

-90

7 4 21

0.50.25

45


Prosthetics

44



45



46



47

Illusions

48

The Hermann grid illusion

Image is in public domain.

49

The most widely cited theorypurported to explain the illusion:

Due to antagonistic center/surround organization, the activity ofON-center retinal ganglion cells whose receptive fields fall into the intersections of the grid produces a smaller response than those neurons whose receptive fields fall elsewhere.

Differently oriented vertical and horizontal lines reduce illusion

50


Please see lecture video or Schiller PH, Carvey CE (2005). "The

Hermann Grid Illusion Revisited." Perception 34 (11): 1375–97.

51

Retinal ganglion cell receptive field layout at an eccentricity of 5 degrees


Please see lecture video or Schiller PH, Carvey CE (2005). "The

Hermann Grid Illusion Revisited." Perception 34 (11): 1375–97.

After-effect illusions explained by the facts and rules of adaptation.

interocular experiments

52

Effects of lesions on vision

53

severe

Summary of lesion deficit magnitudes

VISUAL CAPACITY PLGN MLGN V 4 MT IN

TER

MED

IATE

B

ASI

C V

ISU

AL

FUN

CTI

ON

S

color vision severe none mild none

texture perception severe none mild none

pattern perception fine severe none mild none

shape perception fine coarse

severe none mild none

mild none none none

brightness perception none none none none

coarse scotopic vision none none none none

contrast sensitivity fine

coarse

severe none mild mild

mild none none mild

stereopsis fine

coarse

severe none none none

pronounced none none none

motion perception none moderate none moderate

flicker perception none severe none pronounced

choice of "lesser" stimuli severe none severe none

visual learning not tested not tested severe none

object transformation not tested not tested pronounced not tested

54

Eye-movement control

55

Electrical stimulation triggering eye movements:


56

Please see lecture video or Figure 2 from Schiller, Peter H., and Edward J.

Tehovnik. "Look and See: How the Brain Moves Your Eyes About."Progress in Brain Research 134 (2001): 127-42.

Electrical stimulation triggering eye movements:


57

Please see lecture video or Figure 3 from Schiller, Peter H., and Edward J.Tehovnik. "Look and See: How the Brain Moves Your Eyes About."Progress in Brain Research 134 (2001): 127-42.

Summary of the effects of the GABA agonist muscimol and the GABA antagonist bicuculline

Target selection Visual discrimination

muscimol bicuculline muscimol bicuculline

INTERFERENCE INTERFERENCE

NO EFFECT NO EFFECT

FACILITATION INTERFERENCE

V1 DEFICIT V1

FEF MILD DEFICIT

DEFICIT

FEF

LIP NO EFFECT

NO EFFECT

LIP NO EFFECT

INTERFERENCE FACILITATION Hikosaka and Wurtz SC

58


59

Please see lecture video or Figure 17 from Schiller, Peter H., and Edward J.Tehovnik. "Look and See: How the Brain Moves Your Eyes About."Progress in Brain Research 134 (2001): 127-42.

BS

Auditory system

P

PARIETAL LOBE TEMPORAL LOBE

2

V4

V

Midget

1V

w SC

SN FRONTAL LOBE FEF MEFBS

BG

rate code

vector code

place code

vector code

Midget

w

Parasol

LGN M

Anterior system

2V??

Mixed

?Posterior system

Parasol

MT Somatosensory

system

Olfactory system

Smooth pursuit system

Vergence Accessory Vestibular system optic system system

60

Motion perception

61

62

CXDL

L

LL

L

L

L

L

L

L

L

D

D

D

D

D

D

D

D

D

.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 1.1 1.2 deg

.1 .2 .3 .4 .5

.1 .2 .3 .4 .5 .6 .7 .8

.1 .2 .3 .4 .5 .6 .7 .8 .9

.4.1 .2 .3 .5 .6

.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 deg

.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 deg

deg

deg

1.1

.1 .2 .3 .4 .5 .6 .7 deg

L

D

D

s6

s7

s5s1

s2

s3

s4

DEGREES OF VISUAL ANGLE

DEGREES OF VISUAL ANGLE


Summary of cell types in V1

The central role of the parasol system in motion processing and in the perception of apparent motion.

63

BS

Major Pathways of the Accessory Optic System (AOS) Velocity response of AOS neurons = 0.1-1.0 deg/sec Number of AOS RGCs in rabbit = 7K out of 350K

12

3

Cortex Cerebellum

Ant

climbing fibers Prime axes of retinal

direction-selective neurons

Inferior Olive D

M

L

1

2,3

2,3

NOT

Semicircular canals

Vestibular Nucleus

rate code

Terminal BS Nuclei

vestibulo-ocular reflex 64

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Review, the visual and oculomotor systems · 2020. 12. 30. · The visual and oculomotor systems Peter H. Schiller, year 2013 Review, the visual and oculomotor systems Basic wiring