Neurophysiology - Lecture 16 & 17
Card Set Information
Neurophysiology - Lecture 16 & 17
The distance between two crests or troughs (peak to peak measurement)
Filled with a jelly like fluid, refracts light onto the retina
Where the optic nerve leaves the eye, causes a blind spot
Where accomodation occurs
Center of the retina, focused vision, where light falls when looking straight ahead
Located at the center of the macula, dense # of photoreceptors
A fat lens is a result of ciliary muscles ______ and is used to see _____________.
A flat lens results when ciliary muscles _______ and is used for seeing ___________.
As aging occurs the lens _______, so it is harder for the lens to go _______, which impairs _________ vision.
Nearsightedness, also known as ________, is corrected by a ________ lens to reduce refractive power
__________, or farsightedness, is corrected by a ______ lens to add refractive power.
This condition is corrected by an asymmetric lens to compensate for the asymmetry of the eye's lens.
Increased fluid pressure in the eye causing optic nerve damage and eventually death resulting in blindness
The cones degenerate, central vision is lost, but peripheral vision remains due to the rods.
Clouding of the lens and the lens must be surgically removed and replaced with a plastic one.
3 layers of the Retina
1. Ganglion Cells
2. Bipolar Cells
Ganglion Cells contain
Bipolar Cells contain
Peripheral vision, sensitive to light, high convergence and motion detection
Central vision, sensitive to color, low convergence and fine discrimination
Cones are more concentrated at the _____________
Rods are concentrated more heavily ______________ the fovea
Rods and cones constantly regenerate this protein, because one it changes, it falls off of the receptor
3 types of cones
After about __ minutes in the dark, the rods are more sensitive than the cones
On-center and off-center receptive fields ________ boundaries between light and dark.
Ganglion cells responsible for fine detail. Have small receptive fields, sustained APs and color opponent cells
Ganglion cells than are responsible for movement. Have large receptive fields, are sensitive to low contrast and have fast AP.
Red/green type color opponent ganglion cells are ______ while blue/yellow are ________.
Why do we have parallel processing in the visual system?
Processing each bit of info sequentially would take too long and would be unreliable. Parallel processing is much faster.
mixed info from both visual fields
nasal visual fields cross over at the
same information from one visual field travels along the
Why do we have binocular vision and what does it allow for?
Because the visual fields from both eyes overlap, creating depth perception in the center.
Can use two images taken from slightly different angles and present them next to each other, producing depth perception in once focused image
2 pictures taken from slightly different angles and overlayed. One image is presented to each eye through color filtering glasses, which allows depth perception in a flat field.
Responsible for pupillary light reflex and moves head to orient to a visual image.
__________ layers take info from P-type while ____________ layers take info from m-type
Lateral Geniculate Nucleus organization (dorsal to ventral)
P, K, P, K, P, K, P, K, M, K, M, K
The major input to the LGN is the _________ cortex and the rest of the brain.
Project from layer 1 & 2 of LGN to layer IVCalpha
Project from layers 3-6 of LGN to layer IVCbeta
______ visual cortex cells respond strongly to a given orientation.
_______ visual cortex cells respond strongly to movement in a direction
5 things the primary visual cortex is responsible for.
A complete map of the outside world in the brain
Focuses on the middle of vision
Focuses on contrast
Tuned to straight lines in the environment
Highly sensitive to motion and color
In the extrastriate cortex, the _______ is the 'where' pathway, so motion is analyzed.
________ is the 'what' pathway, detail and color are analyzed.
Dorsal (moves to posterior parietal)
Ventral (moves to inferior temporal cortex)
Damage to V4, loss of color vision (only see black and white), subjects describe the world as depressing and food as unappetizing and hard to taste.
The eyes use the amount of light on the retina to help judge if an area is ________. All other colors are then compared to this baseline _______ color.
Inability to identify common items, but may be able to copy drawing of items and draw items from memory
Inability to recognize faces, including close family and themselves. Damage to IT and the Fusiform Face Area.
Damage to area MT of the brain; loss of ability to perceive motion, though perception of objects is intact
Perception of movement when none exists
Perception of motion in a stationary stimulus after viewing a moving stimulus. Occurs in area MT
Motion Aftereffect (or Waterfall Illusion)
Biological motion is the perception of motion related to living things. This involves the ________ __________ Sulcus
When shown a still that suggests motion, people remember the motion as being ______ along than it actually is. This activates brain areas ___ and ____
MT and MST
Apparent and real motion occur in _____ & _______ (areas of visual cortex)
VI and MT