Chapter 9 Flashcards
Sensation
Perceptual experience when the body interacts with a physical quality of the environment
What type of light are butterflies able to see that we can’t? and snakes?
butterflies can see UV
Snakes can see infrared (night vision)
are longer or shorter light waves more dangerous
shorter
cornea
clear outer covering of the eye providing protection and initial focus
pupil
controls the amount of light that enters the eye
Iris
coloured part of the eye that controls the pupil
lens
helps focus on images by changing shapes and reflecting image to retina
retina
lining on the back of the eye where neural signals are created
fovea
center of view, most focused
optic disc and blind spot
the beginning of the optic nerve where signals leave the eye
In dim light the pupil _________ to get as much light as possible
expands
T/F The lens becomes less flexible with age making it harder to focus
True
Myopia
near-sighted, difficulty focusing on farther items
Hyperopia
far-sighted, difficulty focusing on closer items
Presbyopia
Age related far-sightedness
What part of the eye converts light into neural signals
receptors (rods and cones) in the retina
Which cells in the retina directly respond to light waves
Receptor cells
Where are receptor cells located in the retina
furthest from the light
horizontal cells
allow communication between different nearby receptors
bipolar cells of the retina
pass information from receptors to ganglion cells
amacrine cells
allow communication between nearby ganglion cells
ganglion cells
axons form optic nerve and bring signals to the brain
What part of the rods and cones responds to the light
the outer segment which contains discs that hold pigment molecules that react chemically to the light
are there more rods or cones
rods
where are the cones heavily concentrated?
Fovea
were are there no rods
fovea
distribution of cones allow
focus at fovea and colour vision everywhere
______ are sensitive to light and are important in dim light
rods
Macular degeneration
age related loss of cones in fovea (blind spot in middle of eye)
Retinitis pigmentosa
loss off rods and cones on peripheral retina (tunnel vision)
Axons of ______ form the optic nerve
ganglion cells
Magnocellular (M) cells
ganglion cells that get info from rods
Parvocellular (P) cells
Ganglion cells that get info from cones
Signals from the __________ go to the right visual cortex
left visual field
optic chiasm
point where some visual signals cross to opposite hemisphere
signals from the right half of each retina are from the ____ visual field and processed in the _____ hemisphere
Left, right
LGN
Area in the thalamus which transmits visual signals to the visual cortex
T/F optic nerves send one way signals
True
T/F nerves in the visual cortex send one way signals
F - signals go back and forth due to more complex arrangement
what % of visual neurons synapse in the thalamus where the optic nerve ends
90%
Tectopulvinar pathway
A secondary visual pathway which travels to the superior colliculus in the midbrain, responsible for orientation and reflexive pupil dilation
Retinohypothalamic pathway
secondary visual pathway which makes connections with the SCN in the hypothalamus, triggering the release of sleep hormones
Which cells send signals through the retinohypothalamic pathway
M-cells from rods
Geniculostriate pathway
the main visual neural pathway, through the LGM in the thalamus to the visual cortex and back
What part of the thalamus refines and organizes visual signals
LGN
Retinotopic map
mapped out areas of the retina on the LGN
In the LGN, layers 1-2 are the _____ (P or M) cells
M cells, for light
The left LGN processes the _____
right visual field
_________ of the brain flips the image that is projected on to the retina
visual cortex
the top of the visual field is processed at the ________ of the ________
bottom of the visual cortex
The central part of the visual cortex is larger and processes _______
the fovea (central visual field)
T/F physical energy in the environment does not have perceptive quality, it is our brain that determines perception of these qualities
true
T/F It is common for animals to be colourblind
F - they can often see more colours than us
Colour reflectance
the colour we see is the wavelength reflected off the object from the light
There are 3 different types of ____ which distinguish wavelength and allow us to see colour
cones
what are the 3 types of cones
S-cones (blue)
M-cones (green)
L-cones (red)
Scotopic vision
night vision, where rods are dominant
photopic vision
Vision in day light, where cones and rods allow us to see detail and colour
What colour is brightest with scotopic vision? Photopic?
blue, yellow
purkinje shift
the shift from cone dominated to rod dominated vision at night
Dichromatism
red-green colour deficiency
T/F The mantis shrimp has a record 12 colour receptors and can see more colours than humans
f-cannot see more colours
opponent processing
opponent cells beyond the retina help create colour perception, hence the presence of after images
______ allows for fine colour perception
ratio of cone activity received and processed by opponent neurons
