Neuroscience Exam 3

What is the smallest number of photons of light that are able to elicit a change in membrane potential in a photoreceptor?


a. 13
b. 5
c. 50
d. 1
e. 2
Click the card to flip 👆
1 / 21
Terms in this set (21)
The retina is a layer structure composed of five classes of neurons. Which of the following are true statements with regard to the retina.

a. The cell bodies of the photoreceptors are in the inner plexiform layer.
b. Horizontal cells transmit information from the photoreceptors to the ganglion cells.
c. The axons of the retinal ganglion cells bundle together and exit out the back of the eye to form the optic nerve.
d. Amacrine cells modulate information transmitted from the horizontal cells to the ganglion cells.
e. Bipolar cells transmit information from the photoreceptors to the ganglion cells.
How does RGS9 contribute to inactivation of transducin?

a. It is a kinase that phosphorylates R*.
b. It is a kinase that prevents transducin from interacting with rhodopsin.
c. It competes with Tα for binding to rhodopsin
d. It is a GTPase activating protein which facilitates the hydrolysis of GTP by Tα.
e. It is activated by low levels of calcium, triggering activation of guanylate cyclase.
In order to return to the dark state, a photoreceptor must undergo recovery. Which of the following steps contribute to the return of photoreceptors to the dark state?

a. Activation of guanylate cyclase activating protein
b. Conversion of all-trans retinal back to 11-cis retinal
c. GTP hydrolysis by Tα
d. Activation of rhodopsin by rhodopsin kinase
e. Activation of transducin by GTPase activating protein RGS9
What is the fovea?

a. The place in the retina in which all axons exit the retina to go to the brain.
b. The location in the retina with the highest density of capillaries.
c. The location in the retina most sensitive to low light conditions.
d. The place on the retina with the highest concentration of cones.
e. The location in the retina where light has a direct path to the photoreceptors
Which of the following photoreceptor responses to light explain why there is higher sensitivity in low light and higher acuity in daylight conditions?

a. Cones are important for vision in low light because they are tuned to different wavelengths.
b. The current in rods is larger than that in cones, therefore the same intensity of light will produce a larger response in rods, enabling us to see in low light.
c. The current in cones is longer lasting than that in rods, therefore the acuity of the response is lower in cones because there is less time resolution; the visual field will appear blurry.
d. The current in rods is longer lasting than that in cones, therefore the acuity of the response is lower in rods because there is less time resolution; the visual field will appear blurry.
e. The current in cones is larger than that in rods, therefore the same intensity of light will produce a larger response in cones, enabling us to see in low light.
b. The current in rods is larger than that in cones, therefore the same intensity of light will produce a larger response in rods, enabling us to see in low light.
d. The current in rods is longer lasting than that in cones, therefore the acuity of the response is lower in rods because there is less time resolution; the visual field will appear blurry.
Which of the following statement are true with respect to our color vision?

a. The opponent process theory helps explain how color information is processed and perceived by the brain.
b. The trichromat theory fits with the existence of our three types of cones that have overlapping but distinct spectral sensitivities.
c. The visible spectrum of wavelengths is defined by the range of wavelengths that are detected by our cones.
d. M cones have peak absorption at 430 nm.
e. S cones are the most abundant of the three cones.
a. The opponent process theory helps explain how color information is processed and perceived by the brain.
b. The trichromat theory fits with the existence of our three types of cones that have overlapping but distinct spectral sensitivities.
c. The visible spectrum of wavelengths is defined by the range of wavelengths that are detected by our cones.
Which of the following reasons makes men more likely to be red/green color blind?

a. There are multiple copies of the S gene on the Y chromosome.
b. M and L opsin genes are located close to each other on the X chromosome.
c. M and L opsins probably evolved from a common ancestor.
d. Men have fewer photoreceptors with M and L opsins.
e. Testosterone modulates the absorption of M and L opsins.
Which of the following cell types in the retina produce action potentials? a. Rods b. Cones c. Horizontal Cells d. Retinal Ganglion Cells e. Bipolar Cellsd. Retinal Ganglion CellsWhat is the receptive field of a visual neuron? a. The macula b. The regions of the retina with the highest concentration of cones c. The regions of the retina with the highest concentration of rod d. The part of the visual world that stimulates its activity e. The fovead. The part of the visual world that stimulates its activityWhat is the response of the RGC to the center-ON, surround-OFF stimulus? a. inward rectifying response b. retrograde response c. no response d. hyperpolarization e. depolarizatione. depolarizationWhat is the response of the bipolar cell? a. Because it is an OFF-bipolar cell, it expresses an ionotropic glutamate receptor and is depolarized by light. b. Because it is an OFF-bipolar cell, it expresses an ionotropic glutamate receptor and is hyperpolarized in the light. c. Because it is an ON-bipolar cell it expresses an ionotropic glutamate receptor and is hyperpolarized in the light. d. Because it is an OFF-bipolar cell, it expresses a metabotropic glutamate receptor and is depolarized by light. e. Because it is an ON-bipolar cell, it expresses a metabotropic glutamate receptor and is depolarized by light.e. Because it is an ON-bipolar cell, it expresses a metabotropic glutamate receptor and is depolarized by light.Direction-selective ON-OFF ganglion acquire their direction selectivity from a. the direction of spontaneous retinal waves that occur prior to birth b. molecular guidance cues c. feedback from V1 layer 6 cells on the null side of DSGC dendrites d. lateral inhibition by horizontal cells e. preferential formation of synaptic connections with starburst amacrine cells on the null side of DSGC dendritese. preferential formation of synaptic connections with starburst amacrine cells on the null side of DSGC dendritesLateral inhibition by horizontal cells a. enhances the difference between light-stimulated photoreceptors and their surrounding unstimulated neighbors b. is limited to interactions with a single photoreceptor c. is limited to photoreceptors signaling to OFF bipolar cells d. is mediated by their dendrites which are stimulated by glutamate released from photoreceptors, and which send inhibitory feedback to photoreceptor presynaptic terminals e. provides a mechanism by which downstream retinal ganglion cells can acquire center-surround receptive fieldsa. enhances the difference between light-stimulated photoreceptors and their surrounding unstimulated neighbors d. is mediated by their dendrites which are stimulated by glutamate released from photoreceptors, and which send inhibitory feedback to photoreceptor presynaptic terminals e. provides a mechanism by which downstream retinal ganglion cells can acquire center-surround receptive fieldsWhat type of visual information is coded in the retina? a. Direction b. Abstract boundaries c. Luminance d. Color e. Edgesa. Direction c. Luminance d. ColorTo which areas of the brain do RGCs NOT project? a. Pretectum b. Visual cortex c. LGN d. Superior colliculus e. SCNb. Visual cortexWhich of the following is true of the retinal representation in the visual cortex? a. The visual cortex represents each area of the retina equally. b. Each neuron in V1 represents light information from a single photoreceptor. c. There are more V1 neurons responding to signals originating in the central the retina. d. The fovea has a highly expanded representation in V1. e. There are more V1 neurons responding to signals originating in the periphery of the retina.c. There are more V1 neurons responding to signals originating in the central the retina. d. The fovea has a highly expanded representation in V1.What is the difference between ocular dominance columns and orientation columns? a. Ocular dominance columns are found in the LGN and orientation columns are in the cortex. b. There is no difference between ocular dominance columns and orientation columns. c. Ocular dominance columns are unaffected by monocular deprivation, while orientation columns are disrupted by monocular deprivation. d. Orientation columns are columns of cells that respond to bars of light with a specific orientation (for example, vertical, horizontal); Ocular dominance columns are columns in cells that receive input from either the left or the right eye. e. Ocular dominance columns are alternating columns of cells in the visual cortex that receive input from either the nasal or the temporal regions of the retinas, while orientation columns receive input from either the dorsal or the ventral regions of the retinas.d. Orientation columns are columns of cells that respond to bars of light with a specific orientation (for example, vertical, horizontal); Ocular dominance columns are columns in cells that receive input from either the left or the right eye.What is the known major flow of information through the visual cortex? a. Layer 5 > 2/3 > 6 > 4 b. Layer 4 > 2/3 > 5 > 6 c. Layer 6 > 5 > 4 > 2/3 d. Layer 2/3 > 4 > 5 > 6 e. Layer 5/6 > 2/3 > 4b. Layer 4 > 2/3 > 5 > 6