Chapter 4 Study Guide

Question 1

Retina

Answer 1

Light-sensitive layer in back of eye (start of vision by detecting light)

Question 2

Photoreceptors: Rod vs cones

Answer 2

Rods: low light, black/white, shapes

Cones: more specific detail, work best in bright light, detect color/fine detail

Question 3

Bipolar cells

Answer 3

connect photoreceptors (rods and cones) and take them to RGCs

Question 4

Retinal Ganglion Cells (RCGs)

Answer 4

take info (even more condensed) to brain through the optic nerve

Question 5

Fovea

Answer 5

Center of retina, Straight, sharpest vision (not peripheral)

Question 6

Area V1 (Primary Visual Cortex)

Answer 6

Where brain starts understanding what it’s seeing (orientation, edges, basic features)

Question 7

Orientation Selectivity

Answer 7

V1 neurons firing best to specific angles/edges

Question 8

Retinotopic mapping

Answer 8

Neurons mirror the shape/layout of what you’re seeing

Question 9

Cortical magnification

Answer 9

Brain gives more neurons to the fovea, edges have less

Question 10

The binding problem and feature integration theory

Answer 10

Binding problem: challenge of explaining how the brain processes features and puts them together, see things as a coherent perception of object/experience

FIT: way to explain the binding problem: our brain has the preattentive stage (features processed separately) then focused attention stage (brain glues features together)

***illusory conjunction: brain incorrectly combining features from different objects (happens when attention is limited)

Question 11

7 Gestalt principles of perceptual organization

Answer 11

Basic idea: brain organizes visual input into whole objects
FPSCCCS
1. Figure-Ground: we separate figure (object) from ground (background)

2. Proximity: things close together are seen as part of the same group
3. Similarity: things that look alike are grouped together
4. Continuity: lines and patterns are seen as continuing smoothly rather than broken
5. Closure: brain fills in missing info to complete an object (ex: dotted circle perceived as full circle)
6. Common Fate: things that move together are seen as a group
7. Symmetry: symmetrical objects are seen as belonging together, forming coherent shape

Question 12

Dual Stream Hypothesis (vision)

Answer 12

Vision is processed along two separate pathways after the primary visual cortex (V1)

Ventral: “what” – identity, color, shape TEMPORAL
Dorsal: “where/how” – location, how to interact PARIETAL

Question 13

How are the two streams of vision related to the conditions visual-form agnosia and optic ataxia?

Answer 13

Visual-form agnosia: cannot recognize objects but can reach and grasp them (ventral is affected)

Optic ataxia: can recognize objects but can’t reach for them (dorsal is affected)

Question 14

Three properties of sound waves, how they relate to our perception of sound, and how they are reflected in visualization of sound wave

Answer 14

1. Frequency: how fast wave vibrates, determines pitch, waves more packed together=high frequency
2. Amplitude: height of the wave, determines loudness, higher wave=louder sound
3. Complexity: shape of wave is simple or complex=pure or mixture of tones

Question 15

how are high vs low pitched sounds different on basilar membrane

Answer 15

low are at far end/tip (membrane is more flexible here so better for slower waves), high are at base (near entrance)

Question 16

place vs temporal coding

Answer 16

place: location on the basilar membrane

Temporal: timing of firing tells us the pitch (limitation: can’t do for high frequencies)

Question 17

tonotopic organization

Answer 17

neighboring neurons respond to neighboring frequencies

high frequencies are at the posterior, low frequencies are at anterior

Question 18

Dual stream hypothesis of audition and their functions

Answer 18

Dorsal: where sound is coming from, how to act on it
Ventral: what the sound is

Rhesus Macaque Auditory Cortex research showed that some neurons responded to “what” while some responded to “why” suggesting dual stream