Contents
1: The eye ................................................................................................................................................ 4
Anatomy .............................................................................................................................................. 4
Light ..................................................................................................................................................... 5
Light to electricity ................................................................................................................................ 6
Hecht’s Psychophysical experiment ................................................................................................ 6
Pigment and Perception ...................................................................................................................... 6
Visual pigment regeneration ........................................................................................................... 7
Spectral sensitivity........................................................................................................................... 7
Absorption spectra .......................................................................................................................... 8
Perception ........................................................................................................................................... 8
Lateral inhibition ............................................................................................................................. 8
2: Visual Brain ........................................................................................................................................ 10
Lateral Geniculate Nucleus................................................................................................................ 10
Striate Cortex..................................................................................................................................... 10
Hubel and Wiesel........................................................................................................................... 10
Feature detectors .......................................................................................................................... 12
Maps .............................................................................................................................................. 13
Columns ......................................................................................................................................... 14
Representation of an object .......................................................................................................... 14
Pathways or streams ......................................................................................................................... 15
Ungerleider and Mishkin ............................................................................................................... 15
Milner and Goodale ....................................................................................................................... 15
Types of stimuli ................................................................................................................................. 16
Specialization of neurons .................................................................................................................. 16
Evolution........................................................................................................................................ 16
Experience ..................................................................................................................................... 16
Deficits ............................................................................................................................................... 16
Achromatopsia .............................................................................................................................. 16
Akinetopsia .................................................................................................................................... 17
Damaged visual cortex .................................................................................................................. 17
3: Psychophysics and Colour Perception ............................................................................................... 17
Psychophysics .................................................................................................................................... 17
Detection ....................................................................................................................................... 17
Discrimination ............................................................................................................................... 19
1
, Colour Perception.............................................................................................................................. 20
Detection ....................................................................................................................................... 20
Discrimination ............................................................................................................................... 20
Colour Appearance ........................................................................................................................ 21
Individual Differences .................................................................................................................... 21
Colour ............................................................................................................................................ 21
Usefulness of colour vision ............................................................................................................ 22
4: Object Perception.............................................................................................................................. 22
Gestalt Approach ............................................................................................................................... 22
Gestalt laws of Perceptual Organization ....................................................................................... 22
Perceptual Segregation ................................................................................................................. 24
Construction of Objects..................................................................................................................... 24
David Marr ..................................................................................................................................... 24
Feature Integration Theory ........................................................................................................... 25
Recognition-by-Components Approach ........................................................................................ 26
Intelligence of Object Perception ...................................................................................................... 27
The difficulties for computers. ...................................................................................................... 27
Heuristics ....................................................................................................................................... 27
Top-down processing .................................................................................................................... 27
Object recognition with other senses ............................................................................................... 28
Failures in object recognition ............................................................................................................ 28
Apperceptive agnosia .................................................................................................................... 28
Integrative Agnosia........................................................................................................................ 28
Associative Agnosia ....................................................................................................................... 28
Category Specificity ....................................................................................................................... 29
Prosopagnosia ............................................................................................................................... 29
Face recognition ................................................................................................................................ 29
5: Depth Perception .............................................................................................................................. 29
Monocular Cues................................................................................................................................. 30
Binocular Vision ................................................................................................................................. 31
Combining the cues ........................................................................................................................... 33
Illusions .......................................................................................................................................... 33
6: Action and Motion............................................................................................................................. 33
Information in the environment ....................................................................................................... 33
Eye information ................................................................................................................................. 33
Corollary Discharge Theory ........................................................................................................... 34
2
, The brain............................................................................................................................................ 35
Single neurons ............................................................................................................................... 35
The human body................................................................................................................................ 35
7: Hearing .............................................................................................................................................. 36
Structure of the auditory system ...................................................................................................... 36
Auditory nerve ............................................................................................................................... 38
Brain structures ............................................................................................................................. 39
Operating characteristics .................................................................................................................. 39
Hearing loss ....................................................................................................................................... 40
8: Hearing .............................................................................................................................................. 40
Sound localization ............................................................................................................................. 40
3
, 1: The eye
Anatomy
There are three layers of membrane surrounding the eye. The outer membrane made up of sclera,
which is the white of your eye, the middle membrane is the choroid, which contains most of the
blood vessels, and the retina, which is made up of neurons.
The iris is a donut formed muscle which controls how big the pupil is. When there is less light, the iris
relaxes and more light can enter. This process is automatic and is called the pupillary reflex.
Both the anterior and the posterior chamber are filled with a liquid called aqueous humor. The
vitreous chamber is filled with vitreous humor.
The intraocular pressure, which is the pressure of the chambers with fluid, needs to be greater than
the air pressure, but not too great.
The focal length is the distance from the lens at which the image is in focus far away. The power of
the lens is expressed in diopters, which, is 1/focal length.
The lens is attached to the choroid with zonule fibers. The ciliary muscles also connect the lens to the
choroid. When the ciliary muscles are relaxed, the choroid can pull on the lens through the zonule
fibers, this stretches the lens, resulting in being able to see far away. When the ciliary muscles
contract, they resist the pull of the choroid and the lens is thicker so you can see close by.
The retina contains three main layers, the nuclear layers. These are the outer nuclear layer, the inner
nuclear layer and the ganglion cell layer. These layers have this name because they contain the nuclei
of the various types of neurons in the retina.
The nuclear layers are separated by the synaptic layers, where the neurons synapse with each other.
Towards the back of the eye there is a layer containing the inner and outer segments on the
photoreceptors. The outer segments on the photoreceptors, where transduction occurs, are placed
in the pigment epithelium layer.
The outer nuclear layers contains the rest of the photoreceptors. The inner nuclear layer contains the
bipolar cells, horizontal cells and amacrine cells. The ganglion cell layer contains the ganglion cells.
The synapses among the photoreceptors, bipolar cells and horizontal cells are in the inner synaptic
layer, the others in the outer synaptic layer.
4
1: The eye ................................................................................................................................................ 4
Anatomy .............................................................................................................................................. 4
Light ..................................................................................................................................................... 5
Light to electricity ................................................................................................................................ 6
Hecht’s Psychophysical experiment ................................................................................................ 6
Pigment and Perception ...................................................................................................................... 6
Visual pigment regeneration ........................................................................................................... 7
Spectral sensitivity........................................................................................................................... 7
Absorption spectra .......................................................................................................................... 8
Perception ........................................................................................................................................... 8
Lateral inhibition ............................................................................................................................. 8
2: Visual Brain ........................................................................................................................................ 10
Lateral Geniculate Nucleus................................................................................................................ 10
Striate Cortex..................................................................................................................................... 10
Hubel and Wiesel........................................................................................................................... 10
Feature detectors .......................................................................................................................... 12
Maps .............................................................................................................................................. 13
Columns ......................................................................................................................................... 14
Representation of an object .......................................................................................................... 14
Pathways or streams ......................................................................................................................... 15
Ungerleider and Mishkin ............................................................................................................... 15
Milner and Goodale ....................................................................................................................... 15
Types of stimuli ................................................................................................................................. 16
Specialization of neurons .................................................................................................................. 16
Evolution........................................................................................................................................ 16
Experience ..................................................................................................................................... 16
Deficits ............................................................................................................................................... 16
Achromatopsia .............................................................................................................................. 16
Akinetopsia .................................................................................................................................... 17
Damaged visual cortex .................................................................................................................. 17
3: Psychophysics and Colour Perception ............................................................................................... 17
Psychophysics .................................................................................................................................... 17
Detection ....................................................................................................................................... 17
Discrimination ............................................................................................................................... 19
1
, Colour Perception.............................................................................................................................. 20
Detection ....................................................................................................................................... 20
Discrimination ............................................................................................................................... 20
Colour Appearance ........................................................................................................................ 21
Individual Differences .................................................................................................................... 21
Colour ............................................................................................................................................ 21
Usefulness of colour vision ............................................................................................................ 22
4: Object Perception.............................................................................................................................. 22
Gestalt Approach ............................................................................................................................... 22
Gestalt laws of Perceptual Organization ....................................................................................... 22
Perceptual Segregation ................................................................................................................. 24
Construction of Objects..................................................................................................................... 24
David Marr ..................................................................................................................................... 24
Feature Integration Theory ........................................................................................................... 25
Recognition-by-Components Approach ........................................................................................ 26
Intelligence of Object Perception ...................................................................................................... 27
The difficulties for computers. ...................................................................................................... 27
Heuristics ....................................................................................................................................... 27
Top-down processing .................................................................................................................... 27
Object recognition with other senses ............................................................................................... 28
Failures in object recognition ............................................................................................................ 28
Apperceptive agnosia .................................................................................................................... 28
Integrative Agnosia........................................................................................................................ 28
Associative Agnosia ....................................................................................................................... 28
Category Specificity ....................................................................................................................... 29
Prosopagnosia ............................................................................................................................... 29
Face recognition ................................................................................................................................ 29
5: Depth Perception .............................................................................................................................. 29
Monocular Cues................................................................................................................................. 30
Binocular Vision ................................................................................................................................. 31
Combining the cues ........................................................................................................................... 33
Illusions .......................................................................................................................................... 33
6: Action and Motion............................................................................................................................. 33
Information in the environment ....................................................................................................... 33
Eye information ................................................................................................................................. 33
Corollary Discharge Theory ........................................................................................................... 34
2
, The brain............................................................................................................................................ 35
Single neurons ............................................................................................................................... 35
The human body................................................................................................................................ 35
7: Hearing .............................................................................................................................................. 36
Structure of the auditory system ...................................................................................................... 36
Auditory nerve ............................................................................................................................... 38
Brain structures ............................................................................................................................. 39
Operating characteristics .................................................................................................................. 39
Hearing loss ....................................................................................................................................... 40
8: Hearing .............................................................................................................................................. 40
Sound localization ............................................................................................................................. 40
3
, 1: The eye
Anatomy
There are three layers of membrane surrounding the eye. The outer membrane made up of sclera,
which is the white of your eye, the middle membrane is the choroid, which contains most of the
blood vessels, and the retina, which is made up of neurons.
The iris is a donut formed muscle which controls how big the pupil is. When there is less light, the iris
relaxes and more light can enter. This process is automatic and is called the pupillary reflex.
Both the anterior and the posterior chamber are filled with a liquid called aqueous humor. The
vitreous chamber is filled with vitreous humor.
The intraocular pressure, which is the pressure of the chambers with fluid, needs to be greater than
the air pressure, but not too great.
The focal length is the distance from the lens at which the image is in focus far away. The power of
the lens is expressed in diopters, which, is 1/focal length.
The lens is attached to the choroid with zonule fibers. The ciliary muscles also connect the lens to the
choroid. When the ciliary muscles are relaxed, the choroid can pull on the lens through the zonule
fibers, this stretches the lens, resulting in being able to see far away. When the ciliary muscles
contract, they resist the pull of the choroid and the lens is thicker so you can see close by.
The retina contains three main layers, the nuclear layers. These are the outer nuclear layer, the inner
nuclear layer and the ganglion cell layer. These layers have this name because they contain the nuclei
of the various types of neurons in the retina.
The nuclear layers are separated by the synaptic layers, where the neurons synapse with each other.
Towards the back of the eye there is a layer containing the inner and outer segments on the
photoreceptors. The outer segments on the photoreceptors, where transduction occurs, are placed
in the pigment epithelium layer.
The outer nuclear layers contains the rest of the photoreceptors. The inner nuclear layer contains the
bipolar cells, horizontal cells and amacrine cells. The ganglion cell layer contains the ganglion cells.
The synapses among the photoreceptors, bipolar cells and horizontal cells are in the inner synaptic
layer, the others in the outer synaptic layer.
4
