Sensation and perception

Question 1

What are the different parts of the eye and what is their function?

• also go into detail on the components of the retina

Answer 1

• Cornea = clear outer covering of the eye
• Iris = opens and closes depending on how much light there is and the pupil is in the centre of the iris
• Lens = at the back of the eye behind the iris and it focuses light and bends to distinguish between near and far objects

Remember the curvature of the cornea is fixed whereas the curvature of the lens can change dependent on how near or far an object is away

Retina = where light energy initiates neural activity, it is a light sensitive surface at the back of the eye made up of neurons and photoreceptor cells and its function is to change light into action potentials

parts of the retina

Fovea = region at the centre of the retina and visual field that is specialised for high acuity ( sharpness)

Blind spot (optic disc) = Region of the retina where axons forming the optic nerveleave the eye and where blood vessels enter and leave, Has no photoreceptors

Question 2

What part of the eye is vision the clearest?

Answer 2

• The Fovea
• Photoreceptor cells are very densely packed here

Question 3

What is meant by V1?

Answer 3

• This just refers to the primary visual cortex which is the striate cortex

Question 4

Out of RGCs and V1neurons which has the bigger visual receptive field?

Answer 4

• V1

Question 5

Give some examples of injurys to the visual pathway ?

Answer 5

• Scotoma = Small blind spot in the visual field caused by a small lesion or
  migraines of the visual cortex

-Colour agnosia (achromatopsia) = Inability to recognise colours

• Homonymous hemianopia = Blindness of an entire left or right visual field and it primarily affect V1

Question 6

For complex cells what angle does light need to be shinning from to produce its maximum response?

Answer 6

• 45

Question 7

For complex cells what angle does light need to be shinning from to produce its maximum response?

Answer 7

• 45