How do we sense, perceive, and see the world?

Question 1

retinohypothalamic tract

Answer 1

Neural route formed by axons of photosensitive retinal ganglion cells from the retina to the suprachiasmatic nucleus; allows light to entrain the rhythmic activity of the SCN.

Question 2

fovea

Answer 2

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.

Question 3

photoreceptor

Answer 3

Specialized type of retinal cell that transduces light into neural activity

Question 4

opponent process

Answer 4

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

Question 5

auditory flow

Answer 5

Change in sound heard as a person moves past a sound source or as a sound source moves past a person.

Question 5

blind spot

Answer 5

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.’

Question 6

magnocellular (M) cell

Answer 6

Large-celled visual-system neuron that is sensitive to moving stimuli.

Question 7

extrastriate (secondary visual) cortex

Answer 7

Visual cortical areas outside the striate cortex.

Question 8

color constancy

Answer 8

Phenomenon whereby the perceived color of an object tends to remain constant relative to other colors, regardless of changes in illumination.

Question 8

primary visual cortex (V1)

Answer 8

Striate cortex that receives input from the lateral geniculate nucleus.

Question 9

trichromatic theory

Answer 9

Explanation of color vision based on the coding of three primary colors: red, green, and blue.

Question 10

optic chiasm

Answer 10

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.

Question 10

retina

Answer 10

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

Question 10

visual-form agnosia

Answer 10

Inability to recognize objects or drawings of objects.

Question 11

scotoma

Answer 11

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

Question 13

luminance contrast

Answer 13

The amount of light reflected by an object relative to its surroundings.

Question 14

receptive field

Answer 14

Region of the visual world that stimulates a receptor cell or neuron.

Question 14

retinal ganglion cell (RGC)

Answer 14

One of a group of retinal neurons with axons that give rise to the optic nerve.

Question 14

sensation

Answer 14

Registration of physical stimuli from the environment by the sensory organs.

Question 15

tectopulvinar system

Answer 15

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

Question 17

cone

Answer 17

Photoreceptor specialized for color and high visual acuity.

Question 19

optic ataxia

Answer 19

Deficit in the visual control of reaching and other movements.

Question 21

homonymous hemianopia

Answer 21

Blindness of an entire left or right visual field.

Question 22

quadrantanopia

Answer 22

Blindness of one quadrant of the visual field.

Question 23

rod

Answer 23

Photoreceptor specialized for functioning at low light levels.

Question 25

facial agnosia

Answer 25

Face blindness - the inability to recognize faces; also called prosopagnosia.

Question 26

geniculostriate system

Answer 26

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

Question 28

ocular-dominance column

Answer 28

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

Question 29

topographic map

Answer 29

Spatially organized neural representation of the external world.

Question 30

striate cortex

Answer 30

Primary visual cortex (V1) in the occipital lobe; its striped appearance when stained gives it this name.

Question 31

parvocellular (P) cell

Answer 31

Small-celled visual-system neuron that is sensitive to form and color differences.

Question 32

blob

Answer 32

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

Question 33

visual field

Answer 33

Region of the visual world that is seen by the eyes.

Question 34

optic flow

Answer 34

Streaming of visual stimuli that accompanies an observer’s forward movement through space.

Question 35

cortical column

Answer 35

Cortical organization that represents a functional unit six cortical layers deep and approximately 0.5 millimeter square and that is perpendicular to the cortical surface.

Question 36

perception

Answer 36

Subjective interpretation of sensations by the brain.