S&P Visual System Practicum

Last one!!!!

What is the light range humans can see?

380nm-760nm

What is a unit of light?

A photon

What is the nucleus in the thalamus that is responsible for visual information?

Lateral Geniculate Nucleus (LGN)

What is the opsin in rods called?

Rhodopsin

Are humans monochromatic, dichromatic, or trichromatic?

Trichromatic

Identify and define the 4 monocular cues

• Texture

• Linear Perspective: When the size, shape, or distance of an object can be determined by lines converging at a point on the horizon (ex. train tracks)

• Relative Size: how big something is

• Occlusion: the blocking of things

Identify and define the 2 binocular cues

• Retinal disparity: the slight difference in the images projected onto each retina of our eyes.

• Convergence: inward movement of our eyes as they focus on nearby objects.

Fill in the blank: short S-cones correspond to the color _____, medium ______ correspond to the color green, and _______ L-cones correspond to the color red.

• Blue

• M-cones

• Long

S-cones, M-cones, and L-cones are all what?

Opsins

Identify what scotopic entails:

• Rods

• Best for dim conditions

• Located in the periphery

• Sensitive to motion

Identify what photopic entails:

• Cones

• Best for bright conditions

• Located in the fovea = the center of vision

• Acuity

Define acuity:

Detailed vision, good for fine details

What is the distribution of photoreceptors in the fovea?

The fovea contains mostly cones

• Rods are in the periphery

Define fovea:

The central point of focus

Define pupil:

Hole in the center of the iris where light passes through

Define iris:

Band of muscles that controls light entry, controls the size of the pupil

Define lense:

Responsible for accommodation (near-far focus), bends light that is passing through the eye

Define cornea:

Transparent tissue covering the front of the eye, PROTECTION

What brain structure do the optic nerves cross?

Optic chiasm

Write out the visual pathway from optic nerve to cortex:

Optic nerve → Optic chiasm → Optic tract → Lateral Geniculate Nucleus of the Thalamus → A1/V1/Striate Cortex

What is change blindness?

When a stimulus changes without this being noticed by the observer

Answer these questions about the optic disc:

1. Why is it special?

2. What is it lacking?

3. What exits the optic disc?

1. It is the “bridge” between photoreceptors and the optic nerve

2. It lacks photoreceptors, therefore it is the “blindspot”

3. Axons