Chapter 9: How do we sense, perceive, and see the world

Question 1

Receptive fields

Answer 1

region of sensory space (skin surface) in which a stimulus modalities a receptor’s activity

Question 2

Photoreceptors

Answer 2

the rods and cones that are responsible for converting light into signals that are sent to the brain

Question 3

Topographic map

Answer 3

neural-spatial representation of the body or of the areas of the sensory world perceived by a sensory organ

Question 4

Structure of the eye

Answer 4

Cornea
Clear outer covering

Iris
Opens and closes to allow in more or less light
The hole in the iris is the pupil

Lens
Focuses light
Bends to accommodate near and far objects
First thing to age

Retina (sensory receptors for light are here)
Where light energy initiates neural activity
consists of neurons and photoreceptor cells
Translates light into action potentials
Discriminates wavelengths
Works in a wide range of light intensities

Fovea
Region at the retina that specialized for high acuity
Photoreceptors are packed most densely and where our vision is clearest

Question 5

Structure of the retina

Answer 5

rods and cones -> bipolar cells -> ganglion cells -> optic nerve

Question 6

Parahippocampal place area

Answer 6

identifies places, located in the temporal lobe

Question 7

Fusiform face area

Answer 7

identifies faces, located in the temporal lobe

Question 8

Magnocellular cells

Answer 8

• Magno, large
• Receives input primarily from rods
• Sensitive to light and moving stimuli

Question 9

Parvocellular cells

Answer 9

• Parvo, small
• Receives input primarily from cones
• Sensitive to color

Question 10

Layers of lateral geniculate nucleus

Answer 10

• Layers 3-6 are parvocellular
• Layers 1-2 are magnocellular

Question 11

Visual routes

Answer 11

• Optic chiasm: junction of the optic nerves from each eye
• Axons from the inside half of each retina cross over to the opposite side of the brain
• Axons from the outer half of each retina remain on the same side of the brain
• Information from the left visual field goes to the right side of the brain; information from the right visual field goes to the left side of the brain

Question 12

Geniculostriate visual pathway

Answer 12

Projections from the retina to the lateral geniculate nucleus to the visual cortex

Question 13

Tectopulvinar visual pathways

Answer 13

Projections from the retina to the superior colliculus to the pulvinar (back of the thalamus) to the parietal and temporal visual areas

Question 14

Retinohypothalamic visual pathway

Answer 14

• Synapses in the tiny suprachiasmatic nucleus in the hypothalamus
• Roles in regulating circadian rhythms and in the pupillary reflex

Question 15

Color processing in the LGN

Answer 15

segregation of retinal inputs into different cellular layers characterized by their differential responses to red-green (RG) color (L/M opponent), blue-yellow (BY) color (S-cone opponent) and achromatic (Ach) contrast

Question 16

Dorsal Visual Stream

Answer 16

• Pathway that originates in the occipital cortex and projects to the parietal cortex
• The HOW pathway (how action is to be guided toward objects)

Question 17

Ventral visual stream

Answer 17

• Pathway that originates in the occipital cortex and projects to the temporal cortex
• The WHAT pathway (identifies an object)

Question 18

Color constancy

Answer 18

our ability to perceive colors as relatively constant over varying illuminations

Question 19

Blob regions and interblob regions

Answer 19

blobs: groups of neurons that are sensitive to color assemble in cylindrical shapes

interblobs: areas between blobs which receive the same input, but are sensitive to orientation instead of color

Question 20

Visual-form agnosia

Answer 20

Inability to recognize objects or drawings of objects

Question 21

Color agnosia

Answer 21

(achromatopsia)
Inability to recognize colors

Question 22

Face agnosia

Answer 22

prosopagnosia)
Inability to recognize faces

Question 23

Optic ataxia

Answer 23

Deficit in the visual control of reaching and other movements
Damage to the parietal cortex
Retention of the ability to recognize objects normally