Sensetion And Perception Flashcards
Where does sensation come from?
Our environment
For environmental stimuli to be passed onto the brain they have to be converted into what?
A form that the brain could understand (neural impulses), know as transduction
What does lateral geniculate convert light rays to?
Converts light rays to electrical energy by ganglion cells and these signals travel along the optic nerve through lateral geniculate nuclei
We can only see in 2D but out perception of the world is…
In 3D
Why is the image we create in the retina of the eye upside-down and back-to-front?
So we do not directly translate the exact image of the object
Sight is what?
Indirect
The visual information we receive in our eyes doesn’t come directly from the stimulus, but from where?
From the light (electromagnetic radiation formed from oscillated waves of electrical and magnetic energy) reflected directly off it
How much of the electromagnetic spectrum is visible to us?
We only see a very small part
Light travels in waves that can be defined by what?
Their amplitude and wave length
What is the amplitude of light waves?
Height of wave which is perceived as brightness
What is wave length perceived as in relation to light wave?
It is perceived as colour
A small retinal image can be generated from what?
An object which is up close or far away
The eye has many important structures for focusing light on the relevant structures, what are they?
- Cornea
- lens
- retina
What is the cornea?
Front part of the eye where light enters
What is the lens?
Where the light is focused and can change its shape to do so
What is the retina?
The film that you would find on the back of the eye made up of fovea and optic disc and multiple cells
What is the fovea?
A dip in the retina that has a high concentration of specialised neurons that respond to light energy called cones so that sharp and detailed objects are processed and is the black part which is visible in the eye
What is the optic disc?
Where nerves leave the eye and go onto from the optic nerve which is the first part of the pathway to the brain and is the white part which is visible in they eye and you can often see the blood cells radiating out
What are specialised cells used for capturing light known as?
Photoreceptors
What are photoreceptors connected to?
Bipolar cells which are connected to ganglion cells which go into form the optic nerve
There are two types of photoreceptors, what are they?
- a rod
- a cone
They are named for their shape
What are rods
Primarily black and white detectors and do not give any indication about colour or details but instead used in low light and are concentrated in the peripheral areas of the retina and there are around 120 million rods in the human retina
Cones give rise to what?
Colour sensation and detailed high quality visual equity that are connected at the fovea and there are around 6 million cones in the human retina
There are 3 different types of cones so that maximum amount of wavelengths is absorbed, what are they?
- short responds to blue wavelengths
- medium responds to green wavelengths
- long responds to red wave lengths
The three types of cone cells are compared and this gives rise to what?
Colour vision
The destination for almost all visual information is v1 and v2, where is this?
In the visual cortex which sorts and segregates visual information before being passed onto different regions of the Brain for further processing
What are the three main categories of segregation?
- form
- colour
- motion
Area v3 specialised in what?
The form of an object with additional information about the motion
What does v3 contain?
Specialised cells which respond to the motion of particular edges which would correspond to a stationary object that is in one place is tilting or rotating