Pregunta 1
Pregunta
The primary visual pathway
Pregunta 2
Pregunta
In the optic chiasm fibers from the temporal hemiretinas [blank_start]proceed to the ipsilateral hemisphere[blank_end] and fibers from the nasal hemiretinas [blank_start]cross to the contralateral hemisphere[blank_end].
Pregunta 3
Pregunta
Visible spetrum:
Wavelengths from [blank_start]370[blank_end] to [blank_start]770[blank_end] nm.
Pregunta 4
Pregunta
The optic disc is [blank_start]nasal[blank_end] to the fovea, so signals from the fovea are processed in the [blank_start]ipsilateral[blank_end] hemisphere of V1.
Respuesta
-
nasal
-
temporal
-
ipsilateral
-
contralateral
Pregunta 5
Pregunta
Temporal to the binocular zone are the [blank_start]monocular crescents[blank_end].
Pregunta 6
Pregunta
From V1 a ventral pathway goes to the [blank_start]temporal[blank_end] lobe with information about [blank_start]what[blank_end] the stimulus is and its [blank_start]color[blank_end].
A dorsal pathway goes to the [blank_start]parietal[blank_end] lobe with information about [blank_start]where[blank_end] the stimulus is and its [blank_start]motion[blank_end].
Respuesta
-
temporal
-
parietal
-
occipital
-
frontal
-
what
-
where
-
how big
-
color
-
motion
-
shape
-
speed
-
parietal
-
occipital
-
frontal
-
temporal
-
where
-
what
-
motion
-
color
-
shape
Pregunta 7
Pregunta
Visuotopic maps are more precisly organized at [blank_start]early[blank_end] levels of the pathway.
Pregunta 8
Pregunta
Retinal ganglion encode information about [blank_start]contrast[blank_end] in the visual field.
Respuesta
-
contrast
-
brightness
-
color
-
movement
Pregunta 9
Pregunta
Light is refracted by the [blank_start]cornea[blank_end] and the [blank_start]lens[blank_end] and focused onto the [blank_start]retina[blank_end].
(Alphabetical order)
Pregunta 10
Pregunta
In most vertebrates the [blank_start]cornea[blank_end] is fixed and dynamic focusing is achieved by a flexible [blank_start]lens[blank_end] and the [blank_start]ciliary[blank_end] muscle.
Respuesta
-
cornea
-
lens
-
lens
-
cornea
-
ciliary
-
flexing
-
extending
Pregunta 11
Pregunta
The fovea is free of blood-vessels.
Pregunta 12
Pregunta
In the foveola the proximal neurons of the retina are shifted aside so light has direct access to the photoreceptors.
Pregunta 13
Pregunta
The mammalian retina.
Put layers left and cell types right
Pregunta 14
Pregunta
The vertical pathway down the retina is [blank_start]excitatory and inhibitory[blank_end] and goes from the [blank_start]photoreceptors[blank_end] via [blank_start]bipolar cells[blank_end] to the [blank_start]retinal ganglion cells[blank_end].
Horizontal pathways [blank_start]can be excitatory or inhibitory[blank_end] and include [blank_start]horizontal cells[blank_end] and [blank_start]amacrine cells[blank_end].
Pregunta 15
Pregunta
Retinal Pigmental [blank_start]Epithelium[blank_end] (RPE) is located between the light-sensitive outer segments of the [blank_start]photoreceptors[blank_end] and the blood vessels of the [blank_start]choroid[blank_end].
Respuesta
-
Epithelium
-
Epiderm
-
Epimeninges
-
photoreceptors
-
bipolar cells
-
retinal ganglion cells
-
choroid
-
cornea
Pregunta 16
Pregunta
Bruch's membrane is the [blank_start]innermost[blank_end] layer of the choroid and acts as a [blank_start]diffusion barrier[blank_end] between [blank_start]Retinal Pigmental Epithelium (RTE)[blank_end] and the [blank_start]blood vessels[blank_end].
Pregunta 17
Pregunta
There are approximately [blank_start]100 million[blank_end] rods and [blank_start]6 million[blank_end] cones.
There is only 1 type of [blank_start]rods[blank_end] but 3 types of [blank_start]cones[blank_end].
The fovea contains no [blank_start]rods[blank_end] but is densely packed with small [blank_start]cones[blank_end].
A few millimeters outside the fovea [blank_start]rods greatly outnumber cones[blank_end].
Pregunta 18
Pregunta
[blank_start]Scotopic[blank_end] vision: vision under low-light levels.
[blank_start]Mesopic[blank_end] vision: vision under intermediate lighting conditions.
[blank_start]Photopic[blank_end] vision: vision under well-lit conditions.
Respuesta
-
Scotopic
-
Mesopic
-
Photopic
Pregunta 19
Pregunta
Rods are responsible for [blank_start]scotopic and mesopic[blank_end] vision.
Cones are responsible for [blank_start]photopic[blank_end] vision.
Respuesta
-
scotopic and mesopic
-
scotopic
-
mesopic and photopic
-
photopic
Pregunta 20
Pregunta
Which one is true?
Respuesta
-
Cones are much faster than rods.
-
Rods are much faster than cones.
-
Cones and rods have approximately the same speed.
Pregunta 21
Pregunta
The central part of the fovea is called foveola or foveal [blank_start]pit[blank_end].
The adjacent region is called foveal [blank_start]slope[blank_end].
Pregunta 22
Pregunta
The fovea contains mostly [blank_start]M-[blank_end] and [blank_start]L-[blank_end]cones but only very few [blank_start]S-[blank_end]cones.
Pregunta 23
Pregunta
Receptive field of a visual neuron:
The area [blank_start]in visual space[blank_end] where changes in light intensity (or composition, layout, ...) trigger a change in the neuronal response. This change can be excitatory or/and inhibitory.
Respuesta
-
in visual space
-
on the retina
Pregunta 24
Pregunta
The mitochondria of photoreceptors are contained in their [blank_start]inner segment[blank_end].
Respuesta
-
inner segment
-
outer segment
-
cell body
-
synaptic terminal
Pregunta 25
Pregunta
Outer and inner segments of rods and cones are connected by the [blank_start]central cilium[blank_end] (cc).
Pregunta 26
Pregunta
Absorption of a photon [blank_start]hyperpolarizes[blank_end] photoreceptors and generates [blank_start]OFF[blank_end]-responses.
Respuesta
-
hyperpolarizes
-
depolarizes
-
OFF
-
ON
Pregunta 27
Pregunta
Phototransduction
Rhodopsin is densely packed in the [blank_start]disk membranes[blank_end] of rods. It consists of the protein opsin and the light-absorbing part [blank_start]retinal[blank_end].
In the dark retinal is in the [blank_start]11-cis[blank_end] configuration but absorption of a photon causes a flip to the [blank_start]all-trans[blank_end] configuration.
This causes a change in the opsin to an [blank_start]activated[blank_end] state called [blank_start]metarhodopsin II[blank_end].
Metarhodopsin II can then activate [blank_start]hundreds of molecules[blank_end] called transducin. Transducin in turn [blank_start]activates[blank_end] phosphodiesterase which hydrolizes cGMP and leads to [blank_start]a decrease[blank_end] of the cGMP level.
PDE hydrolizes [blank_start]more than 1000 cGMP[blank_end] per second.
This causes the Na+ and Ca2+ channels to [blank_start]close[blank_end] and a sharp [blank_start]decrease[blank_end] in glutamate release.
The metarhodopsin II splits within minutes to opsin and free [blank_start]all-trans retinal[blank_end]. This is either directly transformed back to 11-cis retinal of first reduced to all-trans-retinol, then to 11-cis retinol and then back to 11-cis retinal.
This happens in [blank_start]the retinal pigment epithelium[blank_end].
Respuesta
-
disk membranes
-
inner segment
-
retinal
-
retinol
-
metarhodopsin
-
11-cis
-
all-trans
-
all-trans
-
11-cis
-
activated
-
inactivated
-
metarhodopsin II
-
metarhodopsin
-
rhodopsin II
-
hundreds of molecules
-
exactly one molecule
-
activates
-
deactivates
-
a decrease
-
an increase
-
more than 1000 cGMP
-
approximately 1 cGMP
-
close
-
open
-
decrease
-
increase
-
all-trans retinal
-
11-cis retinal
-
the retinal pigment epithelium
-
the outer plexiform layer
-
the inner plexiform layer
-
Bruch's membrane
-
the outer nuclear layer
-
the inner nuclear layer
Pregunta 28
Pregunta
Metarhodopsin II can activate hundreds of transducin molecules because
Pregunta 29
Pregunta
Termination of the phototransduction cascade
(1) Metarhodopsin is first phosphorylated and its interaction with [blank_start]transducin[blank_end] is blocked by the protein [blank_start]arrestin[blank_end].
(2) Active transducin has [blank_start]GTPase[blank_end] activity which leads to [blank_start]inactivation[blank_end] of [blank_start]phosphodiesterase[blank_end].
(3) A negative feedback by [blank_start]decrease[blank_end] of [blank_start]Ca2+[blank_end] influx leads to synthesis of new [blank_start]cGMP[blank_end].
Respuesta
-
transducin
-
phosphodiesterase
-
cGMP
-
arrestin
-
cGMP
-
inactivation
-
reactivation
-
Ca2+
-
Na+
-
decrease
-
increase
-
cGMP
-
GTP
-
GDP
-
GMP
-
GTPase
-
GDPase
-
cGMPase
-
phosphodiesterase
-
cGMP
Pregunta 30
Pregunta
cGMP synthesis is 5-10 times higher in [blank_start]cones[blank_end] than in [blank_start]rods[blank_end].
Pregunta 31
Pregunta
Adaptation to light is modulated by changes in the influx of [blank_start]Ca2+[blank_end].
Pregunta 32
Pregunta
Photoreceptors tonically fire action potentials and shut down as a reaction to a light stimulus.
Pregunta 33
Pregunta
Photoreceptors transmit their signals to bipolar and horizontal cells via [blank_start]ribbon[blank_end] synapses.
Their function is not entirely clear but they serve as a hotspot of synaptic vesicle exocytosis as well as a replenishment station.
They disassemble when there is a high concentration of [blank_start]Ca2+[blank_end].
Pregunta 34
Pregunta
Which one is true?
Pregunta 35
Pregunta
Horizontal cells form synapses to [blank_start]photoreceptors[blank_end] in the [blank_start]outer plexiform layer[blank_end], while amacrine cells form synapses to [blank_start]retinal ganglion cells[blank_end] in the [blank_start]inner plexiform layer[blank_end].
Respuesta
-
photoreceptors
-
outer plexiform layer
-
retinal ganglion cells
-
bipolar cells
-
inner plexiform layer
-
outer nuclear layer
-
inner nuclear layer
-
ganglion cell layer
Pregunta 36
Pregunta
The synapses of cones connect [blank_start]to ON and OFF[blank_end] bipolar and horizontal cells and form [blank_start]multiple small ribbons[blank_end].
The synapses of rods connect [blank_start]only to ON[blank_end] bipolar and horizontal cells and form [blank_start]a single large ribbon[blank_end].
Respuesta
-
to ON and OFF
-
only to ON
-
only to OFF
-
multiple small ribbons
-
a single large ribbon
Pregunta 37
Pregunta
Which of these cells fire action potentials?
Respuesta
-
Photoreceptors
-
Horizontal cells
-
Bipolar cells
-
Retinal ganglion cells
Pregunta 38
Pregunta
ON- and OFF-type responses occur for the first time in [blank_start]bipolar cells[blank_end]. The lateral inhibition is mediated by [blank_start]inhibitory[blank_end] [blank_start]horizontal cells[blank_end] which use [blank_start]electrical[blank_end] synapses.
Respuesta
-
bipolar cells
-
photoreceptors
-
retinal ganglion cells
-
inhibitory
-
excitatory
-
horizontal cells
-
amacrine cells
-
electrical
-
chemical
Pregunta 39
Pregunta
Rod ON and cone ON bipolar cells express [blank_start]mGluR6[blank_end] which leads to [blank_start]inhibitory[blank_end] glutamate receptors.
Cone OFF bipolar cells express [blank_start]AMPA-/kainate[blank_end] which leads to [blank_start]excitatory[blank_end] glutamate receptors.
Respuesta
-
mGluR6
-
cGMP
-
PDE
-
inhibitory
-
AMPA-/kainate
-
excitatory
Pregunta 40
Pregunta
Horizontal cells provide negative feedback to cone terminal which leads to a short peak in the cone response and a subsequent smaller steady level.
This is related to the transient response of retinal ganglion ells.
Pregunta 41
Pregunta
There are ON and OFF [blank_start]cone[blank_end] bipolar cells but only [blank_start]ON[blank_end] [blank_start]rod[blank_end] bipolar cells.
Pregunta 42
Pregunta
Rod ON bipolar cells connect to [blank_start]AII amacrine cells[blank_end] which make [blank_start]excitatory[blank_end] [blank_start]gap junctions[blank_end] to ON-cone bipolar cells and [blank_start]glycinergic[blank_end] [blank_start]inhibitory[blank_end] synapses to OFF-cone bipolar cells.
Respuesta
-
AII amacrine cells
-
horizontal cells
-
retinal ganglion cells
-
excitatory
-
inhibitory
-
gap junctions
-
glutamatergic synapses
-
glycinergic
-
glutamatergic
-
GABAergic
-
inhibitory
-
excitatory
Pregunta 43
Pregunta
Responses of retinal ganglion cells ...
Respuesta
-
are independent of absolute brightness and encode relative light intensities of center vs. surround.
-
encode the absolute brightness and differentiation between relative light intensities happens further down the pathway in the visual cortex.
Pregunta 44
Respuesta
-
lens
-
pupil
-
posterior eyechamber
-
anterior eyechamber
-
cornea
-
iris
-
sciliary muscle
-
sclera
-
choroid
-
macula
-
fovea
-
retina
Pregunta 45
Pregunta
Alphabetic:
Low-level processing:
[blank_start]Color[blank_end]
[blank_start]Contrast[blank_end]
[blank_start]Movement direction[blank_end]
[blank_start]Orientation[blank_end]
Intermediate-level processing:
[blank_start]Contour integration[blank_end]
[blank_start]Object motion and shape[blank_end]
[blank_start]Surface depth[blank_end]
[blank_start]Surface properties[blank_end]
High-level processing:
[blank_start]Object identification[blank_end]
Respuesta
-
Color
-
Contrast
-
Movement direction
-
Orientation
-
Contour integration
-
Object motion and shape
-
Surface depth
-
Surface properties
-
Object identification
Pregunta 46
Pregunta
Development of the eye:
The [blank_start]optic cup[blank_end] and the [blank_start]ecto[blank_end]derm form the eye.
The inverted optic cup forms the [blank_start]retina[blank_end], the outer layer the [blank_start]pigment epithelium[blank_end].
The retina is a protrusion of the [blank_start]diencephalon[blank_end].
Respuesta
-
optic cup
-
ecto
-
diencephalon
-
retina
-
pigment epithelium
Pregunta 47
Pregunta
For near vision the lens is [blank_start]round[blank_end] and the ciliary muscle [blank_start]contracted[blank_end], for far vision the lens is [blank_start]flat[blank_end] and the ciliary muscle [blank_start]relaxed[blank_end].
Respuesta
-
round
-
flat
-
contracted
-
relaxed
Pregunta 48
Pregunta
Shortsightedness: [blank_start]Myopia[blank_end]
Farsightedness: [blank_start]Hyperopia[blank_end]
Pregunta 49
Pregunta
Diffusion barriers of the mammalian retina
Pregunta 50
Pregunta
Cortical magnification:
The central [blank_start]10[blank_end] degrees of the retina project to [blank_start]50[blank_end] % of the primary visual cortex.
Pregunta 51
Pregunta
Termination of the phototransduction cascade:
Rhodopsin-kinase [blank_start]phosphorylates[blank_end] metarhodopsin, which then binds arrestin that blocks the interaction with [blank_start]transducin[blank_end] ([blank_start]GDP-GTP[blank_end] exchange).
Active transducin has an intrinsic [blank_start]GTP[blank_end]-ase activity that splits its own GTP to GDP and thereby inactivates [blank_start]phosphodiesterase[blank_end].
The [blank_start]decrease[blank_end] in [blank_start]Ca2+[blank_end] leads to the activation of Guanylate-cyclase by [blank_start]GCAP[blank_end]. This leads to the synthetization of cGMP from [blank_start]GTP[blank_end].
Respuesta
-
phosphorylates
-
hydrolates
-
GDP-GTP
-
GMP-GDP
-
transducin
-
phosphodiesterase
-
cGMP
-
GTP
-
GDP
-
GMP
-
phosphodiesterase
-
cGMP
-
decrease
-
increase
-
Ca2+
-
Na+
-
K+
-
GCAP
-
GCAT
-
GBAP
-
GBBT
-
GTP
-
GDP
-
5'GMP
Pregunta 52
Pregunta
[blank_start]Horizontal[blank_end] cells are responsible for the OFF-surround response of bipolar cells.
Respuesta
-
Horizontal
-
Amacrine
-
Photoreceptor
-
Retinal ganglion
Pregunta 53
Pregunta
Cone-OFF bipolar cells and horizontal cells are excited by glutamate via [blank_start]ionotropic[blank_end] glutamate receptors.
Pregunta 54
Pregunta
Three proposed mechanisms for negative feedback from horizontal cells to photoreceptor cells:
(a) [blank_start]GABA[blank_end] release
(b) Ephaptic modulation by hemi-gap junctions in horizontal cell [blank_start]dendrites[blank_end]
(c) [blank_start]H+[blank_end] modulates presynaptic photoreceptor [blank_start]calcium[blank_end] currents
Respuesta
-
calcium
-
sodium
-
potassium
-
H+
-
Phosphor units
-
NO
-
dendrites
-
axons
-
GABA
-
glycine
-
acetylcholine
Pregunta 55
Pregunta
OFF retinal ganglion cells have their synapses [blank_start]above[blank_end] ON retinal ganglion cells in the [blank_start]inner plexiform layer[blank_end].
Respuesta
-
above
-
below
-
inner plexiform layer
-
outer plexiform layer
-
inner nuclear layer
-
outer nuclear layer
-
ganglion cell layer
Pregunta 56
Pregunta
P retinal ganglion cells have [blank_start]small[blank_end] receptive fields with [blank_start]high spectral sensitivity[blank_end] and project to the [blank_start]ventral stream[blank_end].
M retinal ganglion cells have [blank_start]large[blank_end] receptive fields with [blank_start]broad spectral sensitivity[blank_end] and project to the [blank_start]dorsal stream[blank_end].
Pregunta 57
Pregunta
Metarhodopsin II consists of [blank_start]all-trans[blank_end] [blank_start]retinal[blank_end] bound to opsin. It helps to exchange [blank_start]GDP to GTP[blank_end] on hunderds of transducin molecules to activate them (first amplification step).
Phosphodiesterase has an [blank_start]inhibitor[blank_end] which is [blank_start]removed[blank_end] by active transducin.
The [blank_start]alpha[blank_end]-subunit of active PDE hydrolyzes more than thousand [blank_start]cGMP to 5'GMP[blank_end] per second (second amplification step).
Respuesta
-
all-trans
-
11-cis
-
retinal
-
retinol
-
GDP to GTP
-
GMP to GDP
-
GTP to cGMP
-
inhibitor
-
activator
-
removed
-
produced
-
alpha
-
beta
-
gamma
-
cGMP to 5'GMP
-
cGMP to GDP
-
GDP to GTP
-
GTP to cGMP
-
beta-gamma