Module 2 Lecture 4 Visual system

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PT569 Fundamentals of Neuroscience Flashcards on Module 2 Lecture 4 Visual system, created by Mia Li on 27/02/2018.
Mia Li
Flashcards by Mia Li, updated more than 1 year ago
Mia Li
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Question Answer
Which muscles control the lens of the eye? Ciliary muscle.
What connects the ciliary muscle with the lens? zonule fibers
Normal sight = emmetropia
Nearsighted = myopia
Farsighted = hyperopia
To focus on closer objects, the ciliary muscles have to contract
T/F: Photoreceptors and bipolar cells are neurons. F. They both do NOT produce AP.
Photoreceptors are (depolarized/ hyperpolarized) by light. Hyperpolarization
T/F: Photoreceptors follow a all-or-none hyperpolarization. F. It is graded based on intensity of light.
When it is dark, ____ and ____ ions can flow into the rods due to presenting ______. Sodium and calcium cGMP
In the light, cGMP is reduced _______ and ______ flow is blocked, pushing the rod into a ________ state. sodium and calcium. Hyperpolarized state.
The discs in the rods contain light sensitive proteins _______, which start a cascade that (closes/opens) the sodium/calcium channel. Rhodopsin closes
What happens at the molecular level on opsin? light --> changes in configuration of opsin --> allowing closing of calcium and sodium channels.
Rods and cones are very different photoreceptors. The rods integrate (high/low) accuracy light stimuli, and are good for __________ conditions. Rods: low light and low accuracy.
Which is more specific? cones or rods? Cone
Which is better for color detection? Cones
T/F: there are no rods at the fovea. T.
To differentiate color, cones also have very special gitfs Thri coor od detction are: red green blue
cell bodies of optic nerve are the ganglion cells
The (central/off-center ) ganglia cells are more active when the picture is brighter in the middle. central
Ganglion cells that prefer 'center brighter than edge' are called _______ while those in favor of 'the periphery brighter than center' are called _____. on-center ganglion cells Off-center ganglion cells
The mGluR6 are ______ receptors glutamate
On- and off center is determined in _______ connection to bipolar cells and ganglion cells
center cone cell is connected to _______ and _______ bipolar cells, which in turn are connected to ______ and ______ ganglion cells. on-center and off-center bipolar cells on-center and off-center ganglion cells
match the glutamate receptors with type of bipolar cells 1) mGluR6 2) AMPA kainate mGluR6: inhibitory (depolarization), on-center AMPA kainate: excitatory (hyperpolarization), off-center
Types of glutamate receptors on ganglion cells. AMPA kainate, NMDA (all excitatory)
Describe the downstream effect of light shining on central cone. 1. cone is HYPERpolarized 2. more glutamate 3. on-center bipolar cells are depolarized --> increased firing rate of on-center ganglion cell 4. off-center bipolar cells are hyperpolarized --> decreased firing rate of off-center ganglion cell
Order of visual cortex mapping from the most distal to most central. monocular portion -- binocular portion -- macula
The _____ has the largest cortical representation. fovea
T/F: V1 represents edges moving in different directions. T.
V1 has a spacial map of the movement of edges in different orientations in a _______ structure. pinwheel
The dorsal stream is the wh___ detector of vision. It goes from V1 to ____ to _____. where. V1 - V2 - MT
The ventral stream is the wh___ detector of vision. It goes from V1 to ____ to _____. what. V1 - V2 - V4
Three types of involuntary eye motion are drifts, tremor, microsaccades
T/F: neuron firing rate at a constant object is constant. F. It will adapt and become less active.
Three eye movements maintaining the direction of gaze are 1. saccades, 2. smooth pursuit 3. vergence
Two eye movements maintaining the stabilization of gaze are 1. vestibulo-ocular reflex 2. optokinetic reflex
Saccades are (voluntary/ involuntary) while microsaccades are (voluntary/ involuntary). Saccades: voluntary. Microsaccades: involuntary.
T/F: smooth pursuit is usually initiated with a catch-up saccade T.
Disconjugate is required for ________ vergence
Neurons that fire when an image is in a certain location in the visual field are near neurons that ________. This is represented in the ________. move the fovea to the location. Represented in the superior colliculus.
Neurons in the substantia nigra inhibit eye movement via the ___________. Superior colliculus.
T/F: Neurons in the parietal cortex represent the location of saccade targets but are not focused on the target. T. (easily distracted.
Frontal eye field is more focused on the _______ of the saccade. motor action
Which additional part of the brain controls smooth pursuit? striate cortex -- middle temporal and medial superior temporal -- frontal eye fields dorsolateral pontine nuclei -- vestibular nuclei -- flocculus and vermis of the cerebellum
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