Ch. 9

Question 1

fully colorblind - Rods only - See shades of grey

Answer 1

Achromatopsia

Question 2

lack of red

difficulty with blue/green red/green

Answer 2

Protanopia

Question 3

Lack of Green cones

• difficulty with red/purple and green/purple
• most common - 5% of mean and .4% women

Answer 3

Deuteranopia

Question 4

lack of blue

-difficulty yellow/green and blue/green

Answer 4

Tritanopia

Question 5

Transduce (change) sensory energy into neural activity

Answer 5

Sensory Receptors

Question 6

light energy- chemical energy

Sensory receptors respond to different inputs

Answer 6

vision-

Question 7

air pressure- mechanical energy

Sensory receptors respond to different inputs

Answer 7

auditory

Question 8

mechanical energy

Sensory receptors respond to different inputs

Answer 8

somatosensory

Question 9

chemical molecules

Sensory receptors respond to different inputs

Answer 9

taste and olfaction

Question 10

sensitivity of a sensory system.
-tactile receptors on the fingers vs arm.
-explains why the fingers can discriminate touch remarkably well and the arm
cannot do so as well.

Answer 10

Receptor Density

Question 11

• part of visual world that stimulates a receptor cell or neuron
• Receptors connect to the cortex via 3 or 4 innervating neurons

Answer 11

Receptive fields

Question 12

steam of visual stimuli- forward movement. We have holes in our vision but the brain files in the gaps.

Answer 12

Optic flow

Question 13

change in sound is heard - person moves past a sound source

Answer 13

Auditory flow

Question 14

How do action potentials encode the features of sensations (e.g. purple vs. blue)?

• encoded as increase in neuron firing rate
• increase or decrease - encodes intensity

How do action potentials code the different kinds of sensations (ex: vision vs touch)

• Each sensation processed in different areas of the cortex
• Experience- distinguish different senses
• Separate neural systems distinct pattern of wiring

Answer 14

Sensory coding and Representation (285)

Question 15

very subjective… interpretation of sensory information in brain

Answer 15

Perception (286)

Question 16

• not an objective reproduction of world
• subjective construction of reality that is
• manufactured by the brain.

Answer 16

Visual experience

Question 17

Visible wavelength: About 400 nanometers (violet) to 700 nanometers (red) Nanometer (nm): one-billionth of a meter

Answer 17

The Basics- Visible Light and the structure of the eye (288) KNOW THIS SPECTRUM!!!!

Question 18

• light-sensitive surface at the back of the eye consisting of neurons and photoreceptor cells.

Answer 18

Retina (287)

Question 19

region at the center of the retina that is specialized for high acuity; its receptive fields are at the center of the eye’s visual field.

Answer 19

Fovea (290)

Question 20

photoreceptor specialized for functioning

at low light levels.

Answer 20

rod

Question 21

photoreceptor specialized for color and

high visual acuity.

Answer 21

cone

Question 22

region of the retina where axons
forming the optic nerve leave the eye and
where blood vessels enter and leave; has no
photoreceptors and is thus “blind.”

Answer 22

blind spot

Question 23

(nearsighted)
Inability to focus on distant objects
light focal point falls short of the retina

Answer 23

Myopia

Question 24

(Farsighted)
Inability to focus on near objects
focal point falls beyond the retina

Answer 24

Hyperopia

Question 25

Common in older adults - far sighted

Answer 25

Presbyopia

Question 26

specialized type of retinal cell that transduces light into neural activity (inner and outer segment)

Answer 26

photoreceptor

Question 27

-Absorb light over a range of frequencies - maximal absorptions: - 419 nm “blue” or short wavelength - 531 nm “green” or middle wavelength - 559 nm “red” or long wavelength - Equal numbers of red and green cones - Fewer blue cones

Answer 27

Three Types of Cones (Pigments) (291-292) Figures 9-5 & 9-7

Question 28

-cones - highest at the fovea and decrease precipitously towards the periphery -no rods the fovea rods increase in number around the fovea -Rods decrease gradually in number towards the periphery -No Rods and cones in blind spot -ganglion cell axons exit to brain and blood vessels -(remember the eye is a sphere and has 3 dimensions

Answer 28

Distribution of Rods and Cones

Question 29

projections from the retina to the lateral geniculate nucleus to the visual cortex. -Helps you arrive at the WHAT

Answer 29

Geniculostriate System (295) Figure 9-11

Question 30

projections from the retina to the superior colliculus to the pulvinar (thalamus) to the parietal and temporal visual areas. Helps you arrive at the HOW OR WHERE

Answer 30

Tectopulvinar System

Question 31

junction of the optic nerves, one from each eye, at which the axons from the nasal (inside—nearer the nose) halves of the retinas cross to the opposite side of the brain.

Answer 31

*Crossing the Optic Chiasm (294) Figure 9-10 VERY IMPORTANT*

Question 32

Blindness of one quadrant of the visual field.

Answer 32

quadrantanopia

Question 33

small blind spot in the visual field caused by migraine or by a small lesion of the visual cortex.

Answer 33

scotoma

Question 34

Blindness of an entire left or right visual field.

Answer 34

homonymous hemianopia

Question 35

Destruction of the retina of optic nerve

Answer 35

Monocular Blindness

Question 36

Originates in occipital cortex- parietal cortex - the “how” pathway (how action is guided toward objects) - Also called where pathway

Answer 36

Dorsal Visual Stream

Question 37

- Originates in the occipital cortex - temporal cortex | - the “WHAT” pathway (identifies what an object is)

Answer 37

Ventral Visual Stream

Question 38

``` At least 6 different visual regions Primary Visual cortex (V1) Striate Cortex - input from the LGN Extrastriate (Secondary Visual) Cortex Visual cortical areas ```

Answer 38

Occipital Cortex (298) Figure 9-16

Question 39

region in the visual cortex that contains color-sensitive neurons, as revealed by staining for cytochrome oxidase.

Answer 39

blob | Heterogeneity of V1 (298) Figure 9-17

Question 40

- A retinal ganglion cell (RGC) responds to stimulation of small circular patch of retina=cell’s receptive field - Coding location - Light shone in one place on the retina will activate one ganglion cell - Light shone in another place will activate a different ganglion cell

Answer 40

Coding Location in the Retina

Question 41

- Each LGN cell represents a particular place | - projects to V1- topographic map

Answer 41

Cells in Lateral Geniculate Nucleus have visual fields (301) Figure 9-21

Question 42

Each ganglion cell tells the brain about the amount of light hitting a certain spot on the retina compared with the rest of the retina

Answer 42

Receptive-Field Hierarchy (302) Figure 9-23

Question 43

- Excited when light falls on the center - Inhibited when wight falls on the surround - Light across whole receptive field - weak excited

Answer 43

On-Center cells

Question 44

- excited when light falls on the surround - inhibited when light falls on center - light across the whole receptive field- weak inhibition

Answer 44

Off-center cells

Question 45

explanation of color vision based on the coding of three primary colors: red, green, and blue. - three colors- red, green, and blue - color determined- relative responses of cone type - explain color blindness - limitation: four basic colors, red, blue, green and yellow can’t explain afterimage

Answer 45

Trichromatic theory:

Question 46

explanation of color vision that emphasizes the importance of the apparently opposing pairs of colors: red versus green and blue versus yellow.

Answer 46

Opponent Processing theory (310)

Question 47

Opponent Processing theory & Trichromatic theory; what is this and how does it work? good exam question, why do we need both theories:

Answer 47

need the three cones and we need yellow and we get it through...) ``` Opposition of colors Red vs Green Blue vs Yellow Opponent processing in retinal ganglion cells -on/off center-surround receptive fields - ~60% of retinal ganglion. ```

Question 48

the amount of light reflected by an object relative to its surroundings. Ganglion cells provide information about edges...It’s all about the edges -This allows input from Retinal Ganglion Cells (RGC’s) to tell the brain about shape

Answer 48

Luminance Contrast

Question 49

- Unlike a simple cell’s on–off response pattern, a complex cell in the visual cortex shows the same response throughout its circular receptive field, responding best to bars of light moving at a particular angle. The response is reduced or absent with the bar of light at other orientations.

Answer 49

Complex Cells Figure 9-30 (307)

Question 50

- A hypercomplex cell in the visual cortex responds to a moving bar of light in a particular orientation (horizontal, e.g.) anywhere in the excitatory (ON) part of its receptive field. If most of the bar extends into the inhibitory area (OFF), however, the response is inhibited.

Answer 50

Hypercomplex Cells Figure 9-31 (307)

Question 51

- functional column in the visual cortex maximally responsive to information coming from one eye.

Answer 51

ocular-dominance column (306)

Question 52

cells maximally excited by complex visual stimuli (e.g. faces or hands) - particular faces seen head-on - faces viewed in profile - certain facial expressions - animal faces Stimulus equivalence -Recognize object is the same across different orientations Ventral stream is the “HOW OR WHERE” we recognize

Answer 52

Shape processing - Temporal cortex (308-309) Figure 9-35

Question 53

inability to recognize objects or drawings of objects.

Answer 53

Injury to the “WHAT” pathway (314) | visual-form agnosia (314)

Question 54

Agnosia

Answer 54

Inability recognize previously familiar stimuli

Question 55

Color Agnosia (achromatopsia)

Answer 55

Inability to recognize colors

Question 56

Face Agnosia

Answer 56

Inability to recognize faces

Question 57

Patients with visual-form agnosia cannot recognize objects, they can:

Answer 57

``` copy objects draw objects from memory cannot later recognized copied objects shape their hands appropriately when grasping for objects not able to recognize those objects ```

Question 58

deficit in the visual control of reaching and other movements.

Answer 58

Injury to the “HOW” Pathway (316) | optic ataxia