Vision summary slides
3 views
Skip to first unread message
Diego Ardila
Oct 30, 2012, 3:16:43 PM10/30/12
to bcs...@googlegroups.com
Text dump of all summary slides for your convenience:
1. In primates the right brain receives input from the left visual
hemifield and the left brain
from the right hemifield.
4. There are several classes of RGCs, two of which are (a) the ON
and OFF and (b) the
Midget and Parasol.
2. There are five major classes of retinal cells: photorecptors
(rods and cones), horizontal cells,
bipolar cells, amacrine cells, and retinal ganglion cells (RGC).
3. The receptive fields of RGCs have antagonistic center/surround
organization.
5. All photoreceptors and horizontal cells hyperpolarize to light.
6. There are both hyperpolarizing and depolarizing bipolar cells.
7. Action potentials in the retina are generated only by amacrine and
RGC cells.
8. The lateral geniculate nucleus of the thalamus is a laminated
structure. What is
segregated in the laminae varies with species.
9. The parvocellular layers receive input from the midget cells and
the magnocellular layers
from the parasol cells. Inputs from the left and right eyes are
segregated in the laminae.
10. The receptive field properties of LGN cells are similar to those
of the retinal ganglion cells.
1. The contralateral visual hemifield is laid out topographically in
V1 of each hemisphere.
2. V1 transforms are: orientation, direction, spatial frequency, binocularity,
ON/OFF convergence and midget/parasol convergence.
3. V1 is organized in a modular fashion. Three models of the layout of the
modules are the ice cube, radial and swirl models.
4. There are more than 30 visual areas that make more than 300
interconnections.
5. Extrastriate areas do not specialize in any single function.
6. The receptive field size of neurons increases greatly in
progressively higher
visual areas.
7. Area MT is involved in the analysis of motion , depth, and flicker.
8. Area V4 engages in many aspects of analysis; neurons have dynamic
properties.
9. In inferotemporal cortex high level analysis takes place that
includes object
recognition.
10. Single cells in cortex are multifunctional.
1. All photoreceptors hyperpolarize to light.
2. The cone driven ON and OFF channels originate at the level of
the retinal bipolar cells; sign inversion in ON bipolars is provided
by the mGluR6 receptor.
3. APB is a glutamate analog that blocks the ON bipolar.
4. APB blocks the ON response in retinal ganglion cells; the
OFF response and center/surround antagonism are unaffected.
5. APB blocks light edge response in cortex but has no effect on
orientation, direction and spatial frequency selectivity.
6. APB reduces sensitivity for light increment.
7. In most primates there are only ON rod bipolars. The rod ON and
OFF channels are created in the inner retina by amacrine cells.
8. The ON and OFF channels have emerged in the course of
evolution
to enable organisms to process both light incremental and light
decremental information rapdily and effectively.
1. Two major channels originating in the retina are the midget and the parasol.
2. In central retina the receptive field center of midget RGC and parvocellular
LGN cells is compised of a single cone.
3. Parasol cells have much larger receptive fields; the cone input is mixed
in both the center and the surround.
4. The midget and parasol cell ratio from center to periphery changes from
8 to 1 to 1 to 1.
5. The midget and parasol systems converge on some of the cells in V1.
6. V4 receives input from both the midget and parasol
cells.
7. The major input to MT is from the parasol cells.
8. The midget system extends the range of vision in the wavelength and
high spatial frequency domains
9. The parasol system extends the range of vision in the high temporal
frequency domain.
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.
3. Peak sensitivity of human photoreceptors:
S = 420, M = 530, L = 560, Rods = 500 (One nanometer = one
billionth of a meter)
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.
6. Metamers: stimuli producing different distributions of light energy that
yield the same color sensations.
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.
1. There are three qualities of color: hue, brightness, and saturation.
2. The basic rules of color vision are explained by the color circle.
3. The three cone photoreceptors are broadly tuned.
4. Color-opponent midget RGCs form two cardinal axes, red/green and
blue/yellow.
7. Color is processed in many cortical areas; lesion to any single
extrastriate
structure fails to eliminate the processing of chrominance information.
5. The midget system is essential for color discrimination.
8. Perception at isoluminance is compromised for all categories of vision.
9. The most significant aspects of luminance adaptation occur in the
photoreceptors.
10. Afterimages are a product of photoreceptor adaptation and their subsequent
response to incoming light.
6. The parasol cells can perceive stimuli made visible by chromiance but
cannot ascertain color attributes.
1. Numerous mechanisms for analyzing depth have been identified that include
vergence and accommodation, stereopsis, parallax, shading, and perspective.
2. Several cortical structures process stereopsis utilizing disparity
information;
the number of disparities represented is limited as in the case of
color coding.
3. Utilizing motion parallax for depth processing necessitates
neurons specific
for direction, velocity and differential velocity; several areas,
including V1 and
MT process motion parallax.
4. Area MT contributes to the analysis of motion, motion parallax, depth, and
flicker; however, these analyses are also carried out by several
other structures.
6. Little is known at present about the manner in which information
about shading
and perspective is analyzed by the brain.
5. In some brain areas information processed on the basis of such
cues as stereopsis,
motion paraqllax and shading, is integrated leading to more
accurate and quicker
assessment of depth.
1. Three theories of form precessing in the brain are (a) analysis by
orientation
of line segmens, (b) spatial mapping onto a topographically organized brain
region and (c) Fourier analysis.
2. Areas V2, V4 and IT play important roles in intermediate vision.
3. Neurons responding to subjective contours have been found in V2.
4. Recognition of objects transformed in various ways is compromised by
V4 and IT lesions. V4 lesions also produce major deficits in visual
learning and in selecting "lesser" stimuli.
5. Some IT neurons are selective for objects including faces, but most
respond to a variety of objects whose recognition is based on the
differential activity of a great many neurons.
6. How we process and deal with ambiguities in perception remains a mystery
1. Classes of eye movements are vergence and conjugate, with the latter
comprised of two types, saccadic and smooth pursuit.
2. Eye movements are produced by 6 extraocular muscles that are innervated
by axons of the 3rd, 4th and 6th cranial nerves.
3. The discharge rate in neurons of the final common path is
proportional to the
angular deviation of the eye. Saccade size is a function of the
duration of the
high-frequency burst in these neurons.
4. The superior colliculus codes saccadic vectors whose amplitude and direction
is laid out in an orderly fashion and is in register with the
visual receptive fields.
5. The retinal input to the SC comes predominantly from w-like
cells. The cortical
downflow from V1 is from layer 5 complex cells driven by the
parasol system.
1. Two major cortical systems control visually guided saccadic eye
movements: The anterior
and the posterior.
2. The anterior system has direct access to the brainstem whereas the posterior
system passes through the colliculus.
6. The posterior system is essential for producing express saccades.
7. The FEF plays a central role in the planning of saccadic sequences.
9. The role of the medial eye fields remains a puzzle. It may be
involved in hand-eye
coordination, in establishing spatial relationships and in
visuo-motor learning.
5. Paired ablation of the FEF and SC eliminates visually guided
saccadic eye movements.
4. Areas V1, V2, FEF, LIP and SC carry a vector code. MEF carries a
place code.
8. The posterior system is important for object identification, for
deciding where to look
and where not to look. LIP in addition is important for
deciding when to look. The FEF
and MEF contribute to where to look.
3. Inhibitory circuits, as from the substantia nigra and in the
frontal eye fields, are
essential for generating properly directed saccadic eye-movements.
1. Motion has been classified into several different types that
includes planar, circular,
radial as well as differential for parallax.
2. The majority of V1 cells and most MT cells are directional and
velocity selective.
Some cells are sensitive to differential velocities of movement.
3. The AOS, that begins with RGCs that form three axes of direction
selectivity that
correspond to the three axes of the semicircular canals, is
involved in generating
pursuit eye movements for image stabililization.
6. Stationary stimuli that flicker with various temporal asynchronies
induce apparent motion.
5. Motion cues can provide important information for object
recognition often referred to as
"structure from motion."
4. One of the most important tasks of motion analysis is motion
parallax as it serves
to provide vital information about depth.
1. In primates the right brain receives input from the left visual
hemifield and the left brain
from the right hemifield.
4. There are several classes of RGCs, two of which are (a) the ON
and OFF and (b) the
Midget and Parasol.
2. There are five major classes of retinal cells: photorecptors
(rods and cones), horizontal cells,
bipolar cells, amacrine cells, and retinal ganglion cells (RGC).
3. The receptive fields of RGCs have antagonistic center/surround
organization.
5. All photoreceptors and horizontal cells hyperpolarize to light.
6. There are both hyperpolarizing and depolarizing bipolar cells.
7. Action potentials in the retina are generated only by amacrine and
RGC cells.
8. The lateral geniculate nucleus of the thalamus is a laminated
structure. What is
segregated in the laminae varies with species.
9. The parvocellular layers receive input from the midget cells and
the magnocellular layers
from the parasol cells. Inputs from the left and right eyes are
segregated in the laminae.
10. The receptive field properties of LGN cells are similar to those
of the retinal ganglion cells.
1. The contralateral visual hemifield is laid out topographically in
V1 of each hemisphere.
2. V1 transforms are: orientation, direction, spatial frequency, binocularity,
ON/OFF convergence and midget/parasol convergence.
3. V1 is organized in a modular fashion. Three models of the layout of the
modules are the ice cube, radial and swirl models.
4. There are more than 30 visual areas that make more than 300
interconnections.
5. Extrastriate areas do not specialize in any single function.
6. The receptive field size of neurons increases greatly in
progressively higher
visual areas.
7. Area MT is involved in the analysis of motion , depth, and flicker.
8. Area V4 engages in many aspects of analysis; neurons have dynamic
properties.
9. In inferotemporal cortex high level analysis takes place that
includes object
recognition.
10. Single cells in cortex are multifunctional.
1. All photoreceptors hyperpolarize to light.
2. The cone driven ON and OFF channels originate at the level of
the retinal bipolar cells; sign inversion in ON bipolars is provided
by the mGluR6 receptor.
3. APB is a glutamate analog that blocks the ON bipolar.
4. APB blocks the ON response in retinal ganglion cells; the
OFF response and center/surround antagonism are unaffected.
5. APB blocks light edge response in cortex but has no effect on
orientation, direction and spatial frequency selectivity.
6. APB reduces sensitivity for light increment.
7. In most primates there are only ON rod bipolars. The rod ON and
OFF channels are created in the inner retina by amacrine cells.
8. The ON and OFF channels have emerged in the course of
evolution
to enable organisms to process both light incremental and light
decremental information rapdily and effectively.
1. Two major channels originating in the retina are the midget and the parasol.
2. In central retina the receptive field center of midget RGC and parvocellular
LGN cells is compised of a single cone.
3. Parasol cells have much larger receptive fields; the cone input is mixed
in both the center and the surround.
4. The midget and parasol cell ratio from center to periphery changes from
8 to 1 to 1 to 1.
5. The midget and parasol systems converge on some of the cells in V1.
6. V4 receives input from both the midget and parasol
cells.
7. The major input to MT is from the parasol cells.
8. The midget system extends the range of vision in the wavelength and
high spatial frequency domains
9. The parasol system extends the range of vision in the high temporal
frequency domain.
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.
3. Peak sensitivity of human photoreceptors:
S = 420, M = 530, L = 560, Rods = 500 (One nanometer = one
billionth of a meter)
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.
6. Metamers: stimuli producing different distributions of light energy that
yield the same color sensations.
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.
1. There are three qualities of color: hue, brightness, and saturation.
2. The basic rules of color vision are explained by the color circle.
3. The three cone photoreceptors are broadly tuned.
4. Color-opponent midget RGCs form two cardinal axes, red/green and
blue/yellow.
7. Color is processed in many cortical areas; lesion to any single
extrastriate
structure fails to eliminate the processing of chrominance information.
5. The midget system is essential for color discrimination.
8. Perception at isoluminance is compromised for all categories of vision.
9. The most significant aspects of luminance adaptation occur in the
photoreceptors.
10. Afterimages are a product of photoreceptor adaptation and their subsequent
response to incoming light.
6. The parasol cells can perceive stimuli made visible by chromiance but
cannot ascertain color attributes.
1. Numerous mechanisms for analyzing depth have been identified that include
vergence and accommodation, stereopsis, parallax, shading, and perspective.
2. Several cortical structures process stereopsis utilizing disparity
information;
the number of disparities represented is limited as in the case of
color coding.
3. Utilizing motion parallax for depth processing necessitates
neurons specific
for direction, velocity and differential velocity; several areas,
including V1 and
MT process motion parallax.
4. Area MT contributes to the analysis of motion, motion parallax, depth, and
flicker; however, these analyses are also carried out by several
other structures.
6. Little is known at present about the manner in which information
about shading
and perspective is analyzed by the brain.
5. In some brain areas information processed on the basis of such
cues as stereopsis,
motion paraqllax and shading, is integrated leading to more
accurate and quicker
assessment of depth.
1. Three theories of form precessing in the brain are (a) analysis by
orientation
of line segmens, (b) spatial mapping onto a topographically organized brain
region and (c) Fourier analysis.
2. Areas V2, V4 and IT play important roles in intermediate vision.
3. Neurons responding to subjective contours have been found in V2.
4. Recognition of objects transformed in various ways is compromised by
V4 and IT lesions. V4 lesions also produce major deficits in visual
learning and in selecting "lesser" stimuli.
5. Some IT neurons are selective for objects including faces, but most
respond to a variety of objects whose recognition is based on the
differential activity of a great many neurons.
6. How we process and deal with ambiguities in perception remains a mystery
1. Classes of eye movements are vergence and conjugate, with the latter
comprised of two types, saccadic and smooth pursuit.
2. Eye movements are produced by 6 extraocular muscles that are innervated
by axons of the 3rd, 4th and 6th cranial nerves.
3. The discharge rate in neurons of the final common path is
proportional to the
angular deviation of the eye. Saccade size is a function of the
duration of the
high-frequency burst in these neurons.
4. The superior colliculus codes saccadic vectors whose amplitude and direction
is laid out in an orderly fashion and is in register with the
visual receptive fields.
5. The retinal input to the SC comes predominantly from w-like
cells. The cortical
downflow from V1 is from layer 5 complex cells driven by the
parasol system.
1. Two major cortical systems control visually guided saccadic eye
movements: The anterior
and the posterior.
2. The anterior system has direct access to the brainstem whereas the posterior
system passes through the colliculus.
6. The posterior system is essential for producing express saccades.
7. The FEF plays a central role in the planning of saccadic sequences.
9. The role of the medial eye fields remains a puzzle. It may be
involved in hand-eye
coordination, in establishing spatial relationships and in
visuo-motor learning.
5. Paired ablation of the FEF and SC eliminates visually guided
saccadic eye movements.
4. Areas V1, V2, FEF, LIP and SC carry a vector code. MEF carries a
place code.
8. The posterior system is important for object identification, for
deciding where to look
and where not to look. LIP in addition is important for
deciding when to look. The FEF
and MEF contribute to where to look.
3. Inhibitory circuits, as from the substantia nigra and in the
frontal eye fields, are
essential for generating properly directed saccadic eye-movements.
1. Motion has been classified into several different types that
includes planar, circular,
radial as well as differential for parallax.
2. The majority of V1 cells and most MT cells are directional and
velocity selective.
Some cells are sensitive to differential velocities of movement.
3. The AOS, that begins with RGCs that form three axes of direction
selectivity that
correspond to the three axes of the semicircular canals, is
involved in generating
pursuit eye movements for image stabililization.
6. Stationary stimuli that flicker with various temporal asynchronies
induce apparent motion.
5. Motion cues can provide important information for object
recognition often referred to as
"structure from motion."
4. One of the most important tasks of motion analysis is motion
parallax as it serves
to provide vital information about depth.
Stephen Azariah Allsop
Oct 30, 2012, 3:20:54 PM10/30/12
to bcs...@googlegroups.com
Basically what diego just sent out except as a powerpoint. All the summary points from the lectures
Stephen Allsop
MD/PhD candidate
Harvard Medical School
M.I.T., Dept. of Brain and Cognitive Sciences
________________________________________
From: bcs...@googlegroups.com [bcs...@googlegroups.com] on behalf of Diego Ardila [ard...@MIT.EDU]
Sent: Tuesday, October 30, 2012 3:16 PM
To: bcs...@googlegroups.com
Subject: Vision summary slides
--
Stephen Azariah Allsop
Oct 30, 2012, 4:43:04 PM10/30/12
to bcs...@googlegroups.com
updated with stuff from review that wasn't in there before.
Stephen Allsop
MD/PhD candidate
Harvard Medical School
M.I.T., Dept. of Brain and Cognitive Sciences
________________________________________
From: bcs...@googlegroups.com [bcs...@googlegroups.com] on behalf of Stephen Azariah Allsop [s...@MIT.EDU]
Sent: Tuesday, October 30, 2012 3:20 PM
To: bcs...@googlegroups.com
Subject: RE: Vision summary slides
--
--
Lea Hachigian
Oct 30, 2012, 5:54:02 PM10/30/12
to bcs...@googlegroups.com
Reply all
Reply to author
Forward
0 new messages