L6 Seeing things: Brain part Flashcards
Seeing requires about ______ of the brain get involved
half
You see things _____- it is your _____ which turns the image in the right way
upside down; brain
We have two eyeballs which gives us ________ -comparing two images allows us to determine how ____ a object is from us
depth perception; far away
______ of our memories are determined by what we see
80%
People who are blind can see in their dreams if they are ________
not born blind
Everyone has one eye that is slightly _____ than the other
stronger
What is the biggest nucleus for visual output?
Lateral geniculate nucleus
What does pretectum do?
Reflex control of pupil and lens
What does superior colliculus do?
Orient the movements of head and eyes
Describe the visual processing pathway
Retina -> Lateral geniculate nucleus -> primary visual cortex
The image is ______ when it reaches retina
upside down and right left reversed
The optic nerves approach the brain along intercepting paths and meet at the base of the ________ at a crossing point called the ________
diencephalon; optic chiasm
What does optic chiasm do?
Directs the nerve fibres to their targets on the same or opposite side of the brain
In humans, about __% of the _____ axons in each optic nerves cross over in the chiasm, heading for targets on the opposite side of the brain, and the remaining 40% are directed to brain targets on the _____ side.
60; ganglion cell; same
On the brain side of the chiasm the left and right bundles of ganglion cell axons & nerve fibres from both eyes, are called _____
optic tracts
Axons in the optic tracts have a number of _____ in the brain, the most important one is _______ in the _______
targets; lateral geniculate nucleus; thalamus
________terminating in the LGN form synapses with other neurons and do not progress further into the brain.
Axons of the ganglion cells
Neurons that have received visual info from the ganglion cells radiate out of the ____ and go directly to the ____
thalamus; primary visual cortex
Primary visual cortex are also referred to as ______ / _______
region V1; striate cortex
Contralateral meaning.
on the other side
Ipsilateral meaning.
on the same side
Visual information about the left side is mapped in the _____ and the ______
right lateral geniculate nuclei; right visual cortex areas
The lateral geniculate nucleus is a _____ in the _____ for the visual pathway
relay centre; thalamus
How many layers of neurons does LGN have?
6
In the LGN, visual inputs from the left and right eyes terminate in different _____ so that the neurons projecting to the cortex are excited by input from either the left or the right eye, but not by _____
layers; both
The ______ neurons and the _______ neurons that LGN excite are ________
geniculate; cortical; monocular
There are ______ neurons in the cortex that _____ the inputs from the binocular field
binocular; converge
Area V1 is about __ thick and covers only few square inches of brain
2mm
Which cortex is the first cortex area to receive visual info?
Primary visual cortex/ striate cortex/ V1
What is a transformation of the visual image from retina to V1?
Retinotopic map
The retinotopic map in V1 is _____ so the central ___ degrees of the visual field occupies roughly ____ of V1. This makes sense because of the _______ in the periphery
distorted; 10; half; poor acuity
What is the distortion in retina called?
Cortical magnification
For the purpose of ______, neurons in V1 have the smallest _______ of any visual cortex microscopic regions
accurate spatial encoding; receptor field size
The surface of V1 is functionally organized in a map of the visual field.
Retinotopic map
There are dark and light stripes represent the surface view of the left and right in __________
ocular dominance columns
What contains cells with similar selectivity for the orientation of stimuli?
Orientation columns
What in V1 represent the colour module of functional organization?
Color blobs
Each V1 transmits information to two primary pathways, called the _____ and the ________.
ventral stream; dorsal stream
The dorsal stream begins with ____, goes through _____, then go to the _________ (___) and _____(/) and to the _________.
V1; V2; dorsomedial area; V6; Visual area MT; middle temporal; V5; posterior parietal cortex
Dorsal stream is sometimes called _____ pathway or ____ pathway
where; how
Dorsal stream is associated with _______________, especially when visual information is used to _____ or _____
motion, representation of object locations, and control of the eyes and arms; guide saccades; reaching
The ventral stream begins with ____, goes through ___, then through _____ and to ______.
V1; V2; V4; inferior temporal cortex
The ventral stream, sometimes called the _____ pathway, is associated with ___________ & ___________
what; form recognition and object representation; storage of long-term memory
What is the visual fields of both eyes overlap extensively called?
Binocular field
Rabbits have large monocular fields that give them a ____ field of view around its head. Enabling it to see _________ from almost any direction
circular; predators approaching
Primates have _____ eyes
forward-pointing
Depth is a key feature in determining the ____ of an object
shape
The perception of depth is the ______ between the two eyes’ views of the world, which must be _____ and ______ by the brain.
difference; computed; reconciled
The integration of binocular input begins in the _______, the first level at which ______
primary visual cortex; individual neurons receive signal from both eyes
Binocular neurons are neurons in the visual system that _________
assist in the creation of stereopsis from binocular disparity
Binocular neurons have been found in the ________ where the initial stage of _________ begins
primary visual cortex; binocular convergence
How the two eyes create a perception of depth?
Binocular neurons receive inputs from both the right and left eyes and integrate the signals together
First binocular neurons found in ____- most layer III neurons are ______ (but not layer __)
V1; binocular; IV
Name whether the neurons in the following layers are mono/binocular/both:
Layer III
Layer IVC
Layer VI
Layer III: bino& mono
Layer IVC: mono
Layer VI: mono
Random-dot _____ provide a dramatic demonstration of the global nature of disparity analysis. The image presented to each appears as _____, but when the images are viewed ______ the disparity between array of dots in the two images allows an ______ shape to become visible.
stereograms; noise; binocularly; embedded
Retinal neurons also project to the _____, which bilaterally activates ___________ in the Edinger-Westphal nucleus that cause _______ in the ______ reflex
pretectum; parasympathetic preganglionic neurons; pupilary constriction; pupilary light
The pretectal areas are interconnected through the __________, and thus the reflex causes both _____ (_____) and _________(____) pupillary constriction when a light is shown in one eye
posterior commissure; ipsilateral; direct; contralateral; consensual
The ______ play a critical role in generating orienting eye and head movements to sudden (visual and other sensory) stimuli
superior colliculi
Where is superior colliculus located?
In the dorsal midbrain within the tectal plate
The deep layers of the colliculi receive _______ and help mediate_______ through their _____ connections to ocular motor systems.
multimodal sensory inputs; saccadic eye movements; efferent
What is one of the largest components of the brain?
The tectum (superior colliculus)
Our central vision is ______ in the primary visual cortex.
magnified
Binocular vision allows us ____
stereopsis
