Perception - Fitz

Question 1

What is selective attention

Answer 1

higher order brain centers modify the lower transduction

• can ignore entire systems
• or parts thru filtering

Question 2

What kinds of factors can influence your sensory perception?

Answer 2

1 - receptor
2 - receptor must be functional
3 - receptor mechanisms (threshold, adaptation)
4 - Selective attention
5 - emotions, experience, etc
6 - drugs

Question 3

The result of on/off ganglion cells with center/surround receptive fields allows them to respond strongly to:

Answer 3

contrast

Question 4

What part of the brain reassembles a representation of the world?

Answer 4

Visual cortex

Question 5

Why is strabismus a big deal escpecially for younger individuals?

Answer 5

Strabismus is an imbalance that makes the two eyes have a misalignment of visual axes. After 6 months of age it causes diplopia (double vision) and in younger children the brain can actually suppress the weaker eye and cause permanent decrease in visual acuity. (ambylopia)

Question 6

Describe how color perception occurs:

Answer 6

Luminescense : Long and medium (red+green) (gives you contrast)
Long/Medium Ratio : Red/green difference
Short - (long+medium) : Blue/yellow difference

Question 7

If you have a red/green color blindness, what will also be affected?

Answer 7

Visual Acuity

Question 8

What information is encoded in your ventral stream?

What if you damage it?

Answer 8

Color and form - Acuity
“What” stream

Damage causes Cortical Achromatopsia (keeps you from seeing color and identifying things)

Question 9

What information is encoded in your dorsal stream?

What if you damage it?

Answer 9

motion and depth perception
“Where” Stream

Damage causes Ideomotor Apraxia (can’t execute movements dependent on sight)

Question 10

Why do “on” ganglion cells (GCs) generate action potentials in response to light in the centre of their receptive field?

Answer 10

Bipolar cells invert the signal coming from the photoreceptors.

(REMEMBER: The inversion only happens in ON ganglion cells)

Question 11

One form of congenital stationary nightblindness is due to a defect in the retina-specific metabotropic glutamate receptor in ON bipolar cells. What would be the MOST DIRECT result of this genetic defect?

Inability to detect colour
Inability to perceive colour
Decreased ability to detect motion
Visual field defects
Ideomotor apraxia

Answer 11

Decreased ability to detect motion