1. VISION AND THE BRAIN
1.1. ORGANISATION OF THE VISUAL BRAIN
1.1.1. V3
1.1.1.1. FORM PROCESS
1.1.2. V4
1.1.2.1. COLOUR PROCESS
1.1.2.1.1. ACHROMATOPSIA
1.1.3. V5/MT
1.1.3.1. MOTION PROCESS
1.1.3.1.1. AKINETOPSIA
1.1.4. 3 LIMITATIONS OF HIERARCHICAL VIEW
1.1.4.1. INSTEAD MUST BE SEVERAL OVERLAPPING RECURRENT NETWORKS
1.1.4.2. THERE ACTALLY IS A FEEDFORWARD AND RECURRENT PROCESSING
1.1.4.3. PARALLEL PROCESSING IS MORE IMPORTANT THAN ASSUMED
1.2. VISION AND THE BRAIN
1.2.1. FROM EYE TO CORTEX
1.2.1.1. CONES
1.2.1.1.1. COLOUR VISION AND SHARPNESS OF VISION
1.2.1.1.2. ROD MONOCHROMATISM
1.2.1.2. RODS
1.2.1.2.1. VISION IN DIM LIGHT
1.2.1.3. RETINAL GANGLION CELL
1.2.1.3.1. RECEIVES INPUT FROM A FEW CONES BUT HUNDREDS OF RODS
1.2.1.4. RETINA-GENICULATE-STRIATE PATHWAY
1.2.1.4.1. MAIN PATHWAY BETWEEN EYE AND CORTEX
1.2.1.4.2. RETINOPY
1.2.2. EARLY VISUAL PROCESSING: V1 AND V2
1.2.2.1. RECEPTIVE FIELD
1.2.2.1.1. RETINAL REGION WHERE LIGHT AFFECTS A NEURONS ACTIVITY
1.2.2.2. LATERAL INHIBITION
1.3. DEPENDS ON WHAT WE'RE LOOKING FOR AND AT
1.4. TWO PATHWAYS
1.4.1. P
1.4.1.1. V1
1.4.1.1.1. VENTRAL PATHWAY
1.4.2. M
1.4.2.1. V1
1.4.2.1.1. DORSAL PATHWAY
1.4.3. VENTRAL PATHWAY IS TWICE AS LARGE AS DORSAL PATHWAY
1.5. FUNCTIONAL SPECIALISATION (ZEKI)
1.5.1. DIFFERENT CORTICAL AREAS ARE SPECIALISED FOR DIFFERENT VISUAL FUNCTIONS
1.5.2. STRENGTHS
1.5.2.1. WE NEED TO PROCESS ALL OF AN OBJETS ATTRIBUTES
1.5.2.2. THE REQUIRED PROCESS DIFFERS ACCROS ATTRIBUTES
1.5.3. BINDING PROBLEM
1.5.3.1. BINDING-BY-SYNCHRONY HYPOTHESIS
1.5.4. LIMITATIONS
1.5.4.1. BRAIN AREAS ARE LESS SPECIALIZED THAN THEORY SUGGESTS
1.5.4.2. VISUAL BRAIN IS MORE COMPLEX AND CONNECTED
1.5.4.3. UNSOLVED BINDING PROBLEM
2. TWO VISUAL SYSTEMS: PERCEPTION-ACTION MODEL
2.1. VISUAL SYSTEM PROVIDES US WITH AN INTERNAL REPRESENTATION OF THE EXTERNAL WORLD
2.2. GOODALE AND MILNER
2.2.1. VISION-FOR-PERCEPTION SYSTEM
2.2.1.1. WHAT
2.2.1.1.1. VENTRAL STREAM
2.2.1.1.2. ALLOCENTRIC CODING
2.2.1.1.3. SUSTAINED OVER TIME
2.2.1.1.4. USUALLY LEADS TO CONSCIOUS AWARENESS
2.2.1.1.5. SLOWER
2.2.1.1.6. DEPENDS MORE ON INPUT FROM FOVEA
2.2.2. VISION-FOR-ACTION SYSTEM
2.2.2.1. HOW
2.2.2.1.1. DORSAL STREAM
2.2.2.1.2. EGOCENTRIC CODING
2.2.2.1.3. SHORT-LASTING
2.2.2.1.4. DOESN'T LEAD TO CONSCIOUS AWARENESS
2.2.2.1.5. FASTER
2.2.3. FINDING FROM BRAIN-DAMAGED PATIENTS
2.2.3.1. THERE SHOULD BE A DOUBLE DISSOCIATION
2.2.3.1.1. OPTIC ATAXIA
2.2.3.1.2. VISUAL FORM AGNOSIA
2.2.4. VISUAL ILLUSIONS
2.2.4.1. MULLER-LYER
2.2.4.2. EBBINGHAUS ILLUSION
2.2.4.3. HOLLOW-FACE ILLUSION
2.2.4.4. FINDINGS
2.2.4.4.1. VISION-FOR-PERCEPTION SYSTEM SO ACTIONS SHOULD BE UNAFFECTED
2.2.4.4.2. ACTIONS MAY INVOLVE VISION-FOR-PERCEPTION SYSTEM IF PRECEDED BY CONSCIOUS COGNITIVE PROCESSES
2.2.4.4.3. THE TYPE OF ACTION IS IMPORTANT
2.2.4.4.4. ILLUSION AFFECTS ASSESSED BY GRASPING DECREASES WITH PRACTICE PEOPLE USE FEEDBACK
2.2.4.4.5. MORE ILLUSION EFFECT WHEN THERE IS DELAY
2.2.4.4.6. WE CAN MAKE USE OF PROPRIOCEPTION
2.2.5. ACTION PLANNING+MOTOR RESPONSES
2.2.5.1. WHILE GRASPING ALSO PROCESSING IN VENTRAL STREAM
2.2.5.1.1. ESPECIALLY WHEN ACTIONS INVOLVE CONSCIOUS PROCESSES
2.2.5.1.2. EFFECTIVE VS APPROPRIATE GRASPING
2.2.6. DORSAL STREAM:CONSCIOUS AWARENESS
2.2.6.1. DORSAL PROCESSING IS MORE RELEVANT TO CONSCIOUS VISUAL PERCEPTION THAN ASSUMED
2.2.7. TWO PATHWAYS: UPDATE
2.2.7.1. THERE ARE MORE THAN TWO VISUAL PROCESSING SYSTEMS
2.2.7.1.1. ACTIONS TOWARDS OBJECTS DEPEND ON TWO PARTIALLY SEPARATE DORSAL STREAM
2.2.7.1.2. DORSAL,LATERAL,VENTRAL
3. COLOUR VISION
3.1. COLOUR MAKES OBJECTS STAND OUT HELPS TO RECOGNISE AND CATEGORISE
3.2. THREE MAIN QUALITIES OF COLOUR
3.2.1. HUE
3.2.1.1. COLOUR ITSELF RED VS BLUE
3.2.2. BRIGHTNESS
3.2.2.1. PERCEIVED INTENSITY OF LIGHT
3.2.3. SATURATION
3.2.3.1. AMOUNT OF WHITE PRESENT VIVID OR PALE
3.3. TRICHROMACY THEORY
3.3.1. SENSITIVE TO SHORT-WAVELENGHT LIGHT
3.3.1.1. BLUE
3.3.2. MEDIUM-WAVELENGTH
3.3.2.1. YELLOW-GREEN
3.3.3. LONG-WAVELENGTH
3.3.3.1. ORANGE-RED
3.3.4. MOST STIMULI ACTIVATE TWO OR THREE CONE TYPES THE COLOUR PERCEIVED IS DETERMINED BY THE RELATIVE STIMULATION LEVELS
3.3.5. DICHROMACY
3.3.5.1. ONE CONE CLASS IS MISSING
3.3.5.1.1. RED-GREEN DICHROMACY
3.3.6. DENSITY OF CONES IS HIGHER IN FOVEA
3.3.7. IN DIM LIGHT VISION DEPENDS ON RODS
3.3.8. DOES NOT EXPLAIN WHAT HAPPENS AFTER THE ACTIVATION OF THE CONE RECEPTORS AND NEGATIVE AFTERIMAGES
3.4. OPPONENT-PROCESS THEORY
3.4.1. HERING
3.4.1.1. RED-GREEN CHANNEL
3.4.1.2. BLUE-YELLOW CHANNEL
3.4.1.3. ACHROMATIC CHANNEL
3.5. DUAL-PROCESS THEORY
3.5.1. HURVICH AND JAMESON
3.5.1.1. SIGNALS FROM THE THREE CONE TYPES ARE SENT TO THE OPPONENT CELLS
3.5.1.1.1. ACHROMATIC CHANNEL
3.5.1.1.2. BLUE-YELLOW CHANNEL
3.5.1.1.3. RED-GREEN CHANNEL
3.6. COLOUR CONSTANCY
3.6.1. TENDENCY FOR A SURFACE OR OBJECT TO APPEAR THE SAME COLOUR WHEN THERE ARE CHANGES IN THE WAVELENGTHS CONTAINED IN THE ILLUMINANT
3.6.2. DEPENDS ON---
3.6.2.1. ESTIMATING SCENE ILLUMINATION
3.6.2.2. LOCAL COLOUR CONTRAST
3.6.2.2.1. RETINEX THEORY
3.6.2.3. CONE EXCITATION RATIOS
3.6.2.4. FAMILIARITY
3.6.2.5. CHROMATIC ADAPTATION
3.6.2.5.1. AN OBSERVERS VISUAL SENSITIVITY TO A GIVEN ILLUMINAT DECREASES OVER TIME
3.7. DEPTH PERCEPTION
3.7.1. MONOCULAR CUES (PICTORAL CUES)
3.7.1.1. REQUIRE ONLY ONE EYE
3.7.1.1.1. LINEAR PERCEPTION
3.7.1.1.2. TEXTURE GRADIENT
3.7.1.1.3. INTERPOSITION
3.7.1.1.4. FAMILIAR SIZE
3.7.1.1.5. BLUR
3.7.1.1.6. MOTION PARALLAX
3.7.2. BINOCULAR CUES
3.7.2.1. BINOCULAR DISPARITY
3.7.2.1.1. SLIGHT DIFFERENCE IN THE IMAGES PROJECTED ON THE RETINAS OF THE TWO EYES
3.7.2.1.2. PRODUCES STEREOPSIS THE ABILITY TO PERCEIVE THE WORLD 3D
3.7.3. OCULOMOTOR CUES
3.7.3.1. VERGENCE
3.7.3.1.1. THE EYES TURN INWARDS FOR CLOSER OBJECTS
3.7.3.2. ACCOMODATION
3.7.3.2.1. THICKENING THE EYE'S LENS FOR CLOSER OBJECTS
3.7.4. CUE COMBINATION OR INTEGRATION
3.7.4.1. ADDITIVITY
3.7.4.2. SELECTION
3.7.4.3. LESS AMBIGUOUS CUES ARE MORE RELIABLE
3.7.4.4. A CUE IS MORE RELIABLE IF IT IS CONSISTENT WITH OTHERS
3.7.4.5. MAXIMUM LIKELIHOOD ESTIMATION
3.7.4.5.1. INCLUDES PRIOR KNOWLEDGE
3.7.4.6. IDEAL-OBSERVERS MODEL
3.7.4.6.1. INITIAL PROBABILITIES ARE ALTERED BY NEW DATA
3.7.5. SIZE CONSTANCY
3.7.5.1. TENDENCY FOR AN OBJECT TO APPEAR THE SAME SIZE WHETHER ITS SIZE IN RETINAL IMAGE LARGE OR SMALL
3.7.5.1.1. SIZE-DISTANCE INVARIANCE HYPOTHESIS: PERCEIVED SIZE IS PROPORTIONAL TO PERCEIVED DISTANCE
3.7.5.2. DISTANCE HAS A MINIMAL EFFECT
3.8. PERCEPTION WITHOUT AWARENESS: SUBLIMINAL PERCEPTION
3.8.1. SUBLIMINAL PERCEPTION: STIMULUS PERCEPTION OCCURRING EVEN THOUGH THE STIMULUS BELOW THRESHOLD OF CONSCIOUS AWARENESS
3.8.2. BLINDSIGHT PATIENTS
3.8.2.1. DAMAGE TO V1
3.8.2.1.1. PATIENT'S ABILITY TO DETECT VISUAL STIMULI IN THEIR BLIND FIELD DESPITE DENYING
3.8.2.1.2. ABSENCE OF SELF.REPORTED VISUAL PERFORMANCE WITH ABOVE-CHANCE PERFORMANCE ON FORCED-CHOICE TEST
3.8.2.1.3. BETTER AT DIRECTION OF MOTION THAN QUALITIES
3.8.2.1.4. HAS ACCESS TO LOCATION INFO BUT LACK CONSCIOUS AWARENESS
3.8.2.1.5. BLINDSIGHT VS DEGRADED CONSCIOUS VISION
3.8.2.1.6. EVALUATION
3.8.3. SUBLIMINAL PERCEPTION
3.8.3.1. SUBJECTIVE MEASURES VS OBJECTIVE MEASURES
3.8.3.2. ONLY INFO PERCEIVED WITH AWARENESS CAN CONTROL ACTIONS?
3.8.3.2.1. YES
3.8.3.3. PERCEPTUAL AWARENESS ALL-OR-NONE OR GRADED
3.8.3.3.1. GRADED
3.8.3.4. NEUROIMAGING SHOWS UNAWARE STIMULI STILL ACTIVATE SEVERAL BRAIN AREAS