Sensation and Preception Vision
Introduction
Sensations the elementaryparts of the environment that the brain
uses to create meaning mental process seeing hearing smelling
Preception the processing of stimuli to create a sensory understanding
of the world Cproccesing Sensations
Bottom up processing the processing of physical messages delivered
to the senses
Top down processing the integration of a person's beliefs memories and
expectations into their sensoryexperiences to create a preception
Principle of Gestalt
Preception is more complicated than puttingtogetherpuzzlepieces to form
a
big picture Gestalt stales that we are born with a specific way of
organizing information We can tone out background noise and focus
on a specific task So certain information is
given priority
Principle of proximity objects that are close to 1 another are
grouped together
Principle of similarity objects that are physically similar to 1 another
will be groupedtogether
Principle of closure we see objects as a whole even when a part
is missing
Principle of good continuation if line cross each other or are interrupted we tendto
se cont o 1 to in line ex 2 ke s intersectin are see a 2 not 1 Ke
,Principleof commonfate objects moving together will be grouped together
Visioni from light to sight
1 The
eye
Light is a form of electromagnetic radiation we only see 400 700nanometers
Lensi flexiable piece of tissue located behind
the pupil that focuses light on the retina Lens
changes shape to bringobjects into focus
Thickerlens closerobject Thinnerlens fartheraway
Iris ring of pigmentedmuscletissue surrounding the
pupil Responsible for controlling the diameter of
pupil ooocontrolling amount of
light thatreachesretina
Cornea transparent of the eye Madeupof 3 layers r preforms 804offocusingan image
covering
Anteriorchamber humor liquid filled space btwn the cornea and iris It is routinely
cleanedBlockage causes builtup pressure on
eye the development of glaucoma
Vitreous chamber vitreous humor is a fluid filledspacebehind the lens that provides
support z structure to the eyes lens Fluiddoesn'tchange s can sometimes can have
small pieces of debris floaters that block incominglightrays from the retina
Sclera toughwhite portion of eye Areais vascularized o surrounds cornea
Retina thin layerof tissue on the back of eye that contains the photosensitive
receptor cells rod and cones Rods are more sensitive to low light motion info
and cones are more sensitive to high light detailed info
Chloroid highly vascularized portion of the eye that delivers nutrients to
the photoreceptor cells of the retina
Freea potationsyoffthwegretinasdirectlybehyind thepupilgContains a large concentrationof
, l Mus
y l s i pg g f
e w y g n sg
g
conesor no rods
Optic nerve translates info from the retina r sends that info to the visual cortex The
area the optic nerve occupies on retina leaves a blindspot for our vision where lightis
not processed Brain has to compensate for this lack of information
Light must pass through 5 layers of cells in the retina to arrive to
photosensitive cells aka photoreceptors in the back of the eye
There are 2 types of photoreceptors Rods i mostresponsive to low levels of lightfission
Cones mostresponsive tobrightlighting y communicates info about acuity color
Retina contains 126M photosensitive cells
Darkadaption occurs as rod cones adapt to changes in light
Difference btwn rods r cones is cones are only cells that communicate info aboutwavelength
color of an object
2 Retina
After rods 8 cones react to light they send their messages to bipolar cells
Bipolarcells add together the firing of several photoreceptors a senddifferent
kinds of messages to ganglioncells
Diffusebipolar cells in peripheral vision relieve messages and add together
the experience of the photoreceptors 2 send a single message to the ganglion cell
Midgetbipolar cellsi receive inputfrom only a single cone this message is
only sent to a singleganglion cell
3 Ganglion cells
Ganglion cells part of the ganglion layer of retina Axons of
these cells leave the eye a form optic nerve
Large Ganglion cells M cell Receive signals from the diffuse bipolar
cells Aka mango cells
Introduction
Sensations the elementaryparts of the environment that the brain
uses to create meaning mental process seeing hearing smelling
Preception the processing of stimuli to create a sensory understanding
of the world Cproccesing Sensations
Bottom up processing the processing of physical messages delivered
to the senses
Top down processing the integration of a person's beliefs memories and
expectations into their sensoryexperiences to create a preception
Principle of Gestalt
Preception is more complicated than puttingtogetherpuzzlepieces to form
a
big picture Gestalt stales that we are born with a specific way of
organizing information We can tone out background noise and focus
on a specific task So certain information is
given priority
Principle of proximity objects that are close to 1 another are
grouped together
Principle of similarity objects that are physically similar to 1 another
will be groupedtogether
Principle of closure we see objects as a whole even when a part
is missing
Principle of good continuation if line cross each other or are interrupted we tendto
se cont o 1 to in line ex 2 ke s intersectin are see a 2 not 1 Ke
,Principleof commonfate objects moving together will be grouped together
Visioni from light to sight
1 The
eye
Light is a form of electromagnetic radiation we only see 400 700nanometers
Lensi flexiable piece of tissue located behind
the pupil that focuses light on the retina Lens
changes shape to bringobjects into focus
Thickerlens closerobject Thinnerlens fartheraway
Iris ring of pigmentedmuscletissue surrounding the
pupil Responsible for controlling the diameter of
pupil ooocontrolling amount of
light thatreachesretina
Cornea transparent of the eye Madeupof 3 layers r preforms 804offocusingan image
covering
Anteriorchamber humor liquid filled space btwn the cornea and iris It is routinely
cleanedBlockage causes builtup pressure on
eye the development of glaucoma
Vitreous chamber vitreous humor is a fluid filledspacebehind the lens that provides
support z structure to the eyes lens Fluiddoesn'tchange s can sometimes can have
small pieces of debris floaters that block incominglightrays from the retina
Sclera toughwhite portion of eye Areais vascularized o surrounds cornea
Retina thin layerof tissue on the back of eye that contains the photosensitive
receptor cells rod and cones Rods are more sensitive to low light motion info
and cones are more sensitive to high light detailed info
Chloroid highly vascularized portion of the eye that delivers nutrients to
the photoreceptor cells of the retina
Freea potationsyoffthwegretinasdirectlybehyind thepupilgContains a large concentrationof
, l Mus
y l s i pg g f
e w y g n sg
g
conesor no rods
Optic nerve translates info from the retina r sends that info to the visual cortex The
area the optic nerve occupies on retina leaves a blindspot for our vision where lightis
not processed Brain has to compensate for this lack of information
Light must pass through 5 layers of cells in the retina to arrive to
photosensitive cells aka photoreceptors in the back of the eye
There are 2 types of photoreceptors Rods i mostresponsive to low levels of lightfission
Cones mostresponsive tobrightlighting y communicates info about acuity color
Retina contains 126M photosensitive cells
Darkadaption occurs as rod cones adapt to changes in light
Difference btwn rods r cones is cones are only cells that communicate info aboutwavelength
color of an object
2 Retina
After rods 8 cones react to light they send their messages to bipolar cells
Bipolarcells add together the firing of several photoreceptors a senddifferent
kinds of messages to ganglioncells
Diffusebipolar cells in peripheral vision relieve messages and add together
the experience of the photoreceptors 2 send a single message to the ganglion cell
Midgetbipolar cellsi receive inputfrom only a single cone this message is
only sent to a singleganglion cell
3 Ganglion cells
Ganglion cells part of the ganglion layer of retina Axons of
these cells leave the eye a form optic nerve
Large Ganglion cells M cell Receive signals from the diffuse bipolar
cells Aka mango cells
