16

Question 1

What does it mean that the representation in V1 (BA 17) is retinotopic? What is cortical magnification?

Answer 1

a. Retinotopic – mapping of info on retina is related to the retina, similar to striate cortex
i. Each point on retina is represented by a point on V1 corresponding to a
receptor cell
ii. Each receptor has about the same cortical tissue as the other.
b. Cortical magnification – disproportionate allocation of cortical tissue to process sensory information, more neurons are dedicated to processing central visual field than periphery
i. More neurons in cortex to process information from fovea compared with information from peripheral retina

Question 2

What do the simple, complex and hypercomplex cells respond to (see book)?

Answer 2

Question 3

What is processed in MT (V5), and V4?

Answer 3

a. MT (V5) – Motion
b. V4 – Color

Question 4

What is processed in the fusiform face area, the fusiform body area and the parahippocampal place area?

Answer 4

a. VENTRAL – vision for identification
i. Fusiform face area - face analysis
ii. Fusiform body area - body parts, hands, limbs
iii. Parahippocampal place area - landscapes

Question 5

What is a scotoma? What is hemianopia?

Answer 5

a. Scotoma – blind spot or area of reduced vision within the visual field
b. Hemianopia – loss of vision in half of the visual field, either the right or left side

Question 6

Know what the effect for the visual field is of lesions along the optic tract.

Answer 6

Lesions on either side of the optic tract cause hemianopias

Question 7

7. What are the symptoms of akinetopsia, what are they thought to be the result of? How common is this disorder?

Answer 7

a. Akinetopsia – inability to identify objects in motion
i. result of brain lesions in posterior side of visual cortext, damaged V5 (MT), very
very rare, only few cases

Question 8

What are the symptoms of achromatopsia, what are they thought to be the result of in the cerebral form? How common is this disorder?

Answer 8

a. Achromatopsia – inability to detect color
i. result in cerebral form – V4 and V8 cortex are aabsent on both sides of the
brain, or damage of V4 (color processing), very very rare
ii. Cerebral bilateral achromatopsia – both V4s are hit → less rare
iii. Hemiachromatopsia – 1 V4 is hit
iv. Retinal Achromatopsia – certian pigments not in retina

Question 9

What is the apparent function of V4 in terms of color perception?

Answer 9

a. organizes color by chromaticity, color constancy, color outside of context is the same, color perception derives from context