The visual brain

Question 1

Refractive structures of the eye

Answer 1

Cornea and lens

Question 2

Problems with focusing the light through the cornea and lens

Answer 2

Cataract, myopia, presbyopia

Question 3

Myopia

Answer 3

Near-sightedness

Question 4

Presbyopia

Answer 4

Age-related far-sightedness

Question 5

Anatomy of an eye

Answer 5

Pupil, Macula lutea, Fovea centralis, Optic disc, Optic nerve

Question 6

Macula lutea

Answer 6

Yellow spot, central area of the retina where the light rays are focused

Question 7

Fovea centralis

Answer 7

The center of the macula, responsible for the highest visual acuity and colour

Question 8

Optic disc

Answer 8

Axons of retinal ganglion cells leave the eye at the optic disc and form the optic nerve

Question 9

Retinal organization - neurons

Answer 9

Retinal ganglion cells, interneurons, photoreceptors

Question 10

Retinal ganglion cells

Answer 10

Receive information from the photoreceptors via the interneurons, the only retinal neurons whose axons leave the brain

Question 11

Photoreceptors

Answer 11

Rods and cones, respond to reflected light and convert it into a neural signal

Question 12

Rods

Answer 12

Ca. 120 million, very sensitive to light (night vision), multiple rods converge on the same interneuron

Question 13

Cones

Answer 13

Ca. 6 million, less sensitive to light (day vision), 3 types of cones (red, green, blue), one-to-one convergence with an interneuron

Question 14

Saccades

Answer 14

Rapid eye movement to shift visual fixation from one point to another

Question 15

Microsaccades

Answer 15

A type of fixational eye movement produced during visual fixation

Question 16

Left visual hemifield

Answer 16

Seen by the nasal left retina and temporal right retina

Question 17

Right visual hemifield

Answer 17

Seen by the nasal right retina and temporal left retina

Question 18

Visual pathways

Answer 18

Optic nerve, optic chiasm, optic tract, thalamus (LGN) and optic radiaton (Geniculocortical pathway)

Question 19

Optic nerve

Answer 19

Splits into temporal and nasal branch

Question 20

Optic chiasm

Answer 20

Crossover of optic nerve branches

Question 21

Optic tract

Answer 21

Information from the left visual field travels in the right optic tract and information from the right visual field travels in the left optic tract

Question 22

Thalamus (LGN)

Answer 22

Is the major target of the retinal ganglion cells, receives information from both eyes and sends it to V1

Question 23

Lateral geniculate nucleus

Answer 23

6 layers, 2 types of cells

Question 24

Midget (parvocellular)

Answer 24

Receives small details from cones, makes up 4 layers of the LGN

Question 25

Parasol (magnocellular)

Answer 25

Receives information from a bigger area via rods, makes up 2 layers of the LGN

Question 26

V1

Answer 26

Elementary features of objects

Question 27

Hubbel and Wiesel

Answer 27

Single cell recordings in the cat visual cortex

Question 28

Neurons in V1 are selective for?

Answer 28

Position and orientation of edges and direction of movement of edges (bars)

Question 29

Magnocellular pathway

Answer 29

Movement and direction

Question 30

Parvocellular pathway

Answer 30

Colour and orientation

Question 31

V2 and V3

Answer 31

Relay of information, integration of elementary features and motion (especially V3)

Question 32

V4

Answer 32

Colour perception

Question 33

V5/MT

Answer 33

Motion perception

Question 34

Inferior temporal cortex (IT)

Answer 34

Stronger responses to objects than non-objects

Question 35

Fusiform face area (FFA)

Answer 35

Responds to faces

Question 36

Extrastriate body area (EBA)

Answer 36

Responds to bodies

Question 37

Parahippocampal place are (PPA)

Answer 37

Responds to places

Question 38

ERPs

Answer 38

A method of measuring brain activity during cognitive processing, using EEG

Question 39

Dorsal "WHERE" pathway

Answer 39

Magnocellular, carries information about motion and localization, towards parietal cortex

Question 40

Ventral "WHAT" pathway

Answer 40

Parvocellular, carries information about form discrimination and object identification, towards temporal cortex

Question 41

Blindsight

Answer 41

"When the blind can see", Lawrence Weiskrantz

Question 42

Explanations for blindsight

Answer 42

Subcortical visual pathway (superior colliculus), geniculo-extrastriaste pathway, residual V1 function

Question 43

Akinetopsia

Answer 43

Lesion in V5/MT, loss of motion perception

Question 44

Cerebral achromatopsia

Answer 44

Lesion in V4, loss of color perception

Question 45

Visual agnosia

Answer 45

Lesion in the occipito-temporal cortex, results in poor object recognition

Question 46

Apperceptive agnosia

Answer 46

When a person cannot name, copy, match or discriminate visual objects

Question 47

Integrative agnosia

Answer 47

When a person is unable to "put the pieces together"

Question 48

Associative agnosia

Answer 48

When a person is unable to access knowledge of an object's functions and associations

Question 49

Prosopagnosia

Answer 49

Lesion in FFA, loss of face recognition

Question 50

Optic ataxia

Answer 50

Lesion in parietal cortex, person can identify but not grab object