Question 1

Which one of the following statements about temporal responses is not correct?
A) It refers to a cell's receptive field location.
B) A cell with a sustained (tonic) temporal response has a relatively high level of activity during the presence of a stimulus.
C) A cell with a transient (phasic) temporal response shows a brief change in activity at stimulus onset and offset, but relatively little activity during constant stimulation.
D) Midget and parasol ganglion cells have different temporal responses.

Accepted Answer

Temporal response refers to the way in which a cell's firing rate changes over time in response to a stimulus. It does not refer to a cell's receptive field location, which is the region of space in which a stimulus can evoke a response from the cell.

Question 2

Which description of partial decussation is incorrect
A) Means that each LGN receives input from only one eye.
B) Is a property of the optic nerve.
C) Occurs at the optic chiasma.
D) Means that each cortical hemisphere receives input from the contralateral half of the visual field.

Accepted Answer

Partial decussation occurs when the nasal (inner) half of each retina crosses over to the opposite side of the brain at the optic chiasm, while the temporal (outer) half remains on the same side. This means that each LGN (lateral geniculate nucleus) receives input from both eyes, with the information from the contralateral visual field being processed in the opposite LGN. Therefore, each cortical hemisphere receives input from both eyes, with each side processing the contralateral half of the visual field.

Question 3

Which one of the following is the correct term to describe the process in which a cell is excited when light falls in one part of its receptive field, and inhibited when light falls in another part?
A) spatial opponency
B) binocularity
C) sustained temporal response
D) transient temporal response

Accepted Answer

Spatial opponency describes the process in which a cell is excited when light falls in one part of its receptive field, and inhibited when light falls in another part. This is a common mechanism in vision processing, particularly in the retina and visual cortex. The other options (binocularity, sustained temporal response, transient temporal response) do not accurately describe this process.

Question 4

Which one of the following is not associated with the functional architecture of striate cortex (V1)?
A) ocular dominance columns
B) orientation columns
C) blobs
D) Cytochrome oxidase stripes

Accepted Answer

Cytochrome oxidase stripes are associated with V2, not V1. V1 features ocular dominance columns, orientation columns, and blobs, all of which are integral to its functional architecture.

Question 5

Which statement is correct? Simple cells:
A) Have a receptive field that can be mapped into excitatory and inhibitory zones.
B) Are not orientation selective.
C) Respond well regardless of exact stimulus position in the receptive field.
D) Are the most common type of cortical cell.

Accepted Answer

Simple cells have a receptive field that can be divided into excitatory and inhibitory zones, allowing for orientation selectivity. They also exhibit some degree of position selectivity within their receptive fields. While they are a common type of cortical cell, they are not the most common.

Question 6

Which one of the following statements about bipolar cells is not correct?
A) Bipolar cells transmit action potentials.
B) ON bipolars are activated by an increase in the photon catch of receptors.
C) OFF bipolars are activated by a decrease in the photon catch of receptors.
D) Some bipolars connect only to cones, others connect only to rods.

Accepted Answer

Bipolar cells do not transmit action potentials, they transmit graded potentials. The action potentials are generated by ganglion cells which receive input from bipolar cells.

Question 7

Which of the following terms is the correct name for a class of retinal cell whose axons spread laterally across the retina, making contact with several photoreceptors.
A) Amacrine cells
B) Cone bipolar cells
C) Rod bipolar cells
D) Horizontal cells

Accepted Answer

Horizontal cells are the correct name for the class of retinal cells described. They are interneurons that receive input from photoreceptors and send lateral connections to other photoreceptors, allowing for lateral inhibition and contrast enhancement. Amacrine cells, cone bipolar cells, and rod bipolar cells are different types of retinal cells with distinct functions.

Question 8

Which area of visual cortex contains the highest proportions of motion and disparity selective cells?
A) MT
B) V1
C) V2
D) V3

Accepted Answer

MT (also known as V5) is known to contain the highest proportions of cells that are selective for motion and disparity.

Question 9

Lesions affecting which visual cortical area usually result in a complete loss of visual function in the affected area?
A) MT
B) V1
C) V2
D) V3

Accepted Answer

V1, also known as the primary visual cortex or striate cortex, is responsible for the initial processing of visual information. Lesions to this area typically result in a complete loss of vision in the affected area, known as a scotoma.

Question 10

Beyond striate cortex a number of visually responsive cortical areas have been identified on the basis of several criteria, which one of the following is not one of these criteria?
A) topographic organisation
B) relative size
C) anatomical connections
D) cell response properties

Accepted Answer

Relative size is not a criteria used to identify visually responsive cortical areas, while topographic organisation, anatomical connections and cell response properties are commonly used.

Question 11

Cortical cells demonstrate many different forms of stimulus selectivity, which one of these is not associated with striate cortex?
A) orientation tuning
B) direction selectivity
C) binocularity
D) optic flow

Accepted Answer

Optic flow is not typically associated with striate cortex, but rather with higher visual areas involved in processing motion perception and navigation. Orientation tuning, direction selectivity, and binocularity are all well-established properties of striate cortex.

Question 12

How many layers of cell nuclei does the retina contain?
A) 2
B) 3
C) 4
D) 5

Accepted Answer

The retina contains three layers of cell nuclei - the outer nuclear layer, the inner nuclear layer, and the ganglion cell layer.

Question 13

Which one of the following statements describes the Stiles-Crawford effect?
A) Photons arriving near the edge of the pupil are less likely to be absorbed.
B) Photons are some frequencies are less likely to be absorbed by a photoreceptor than those at other frequencies
C) Only two-thirds of the photons absorbed by a photoreceptor actually result in a response
D) When a photon is absorbed, its effect on a photoreceptor is the same regardless of the photon's wavelength.

Accepted Answer

The Stiles-Crawford effect describes the phenomenon where light entering the eye near the pupil's edge is less effective in producing a visual response compared to light entering near the center. This is due to the directional sensitivity of the cones in the retina, which are more efficient at absorbing light that travels perpendicularly to the retina.

Question 14

Which one of the following are not ganglion cells?
A) Amacrine
B) Biplexiform
C) Bistratified
D) Midget
E) Parasol

Accepted Answer

Amacrine cells are not ganglion cells; they are interneurons in the retina that interact with bipolar cells and ganglion cells.

Question 15

Which of the following statements about chromatic opponency is incorrect?
A) spectral opponency is restricted to peripheral vision
B) Bistratified ganglion cells show blue-yellow opponency
C) Parasol ganglion cells do not show spectral opponency
D) Midget ganglion cells show red-green opponency

Accepted Answer

Spectral opponency is not restricted to peripheral vision; it is a characteristic of the visual system that involves the center-surround organization of photoreceptor inputs to ganglion cells, allowing for the perception of color contrasts across the visual field, not just in peripheral vision.

Question 16

Which ganglion cell class is the most numerous and responds only at high light levels?
A) parasol ganglion cell
B) bistratified ganglion cell
C) midget ganglion cell
D) biplexiform ganglion cell

Accepted Answer

Midget ganglion cells are the most numerous in the human retina and are primarily responsible for high-acuity vision in good lighting conditions, responding optimally at high light levels.

Question 17

Where do approximately 90% of ganglion cell fibres project?
A) Suprachiasmatic nuclei
B) Pretectum
C) Lateral geniculate nuclei
D) Superior colliculi

Accepted Answer

Approximately 90% of ganglion cell fibers project to the lateral geniculate nuclei, which are responsible for relaying visual information to the primary visual cortex. The remaining 10% project to other regions, such as the pretectum and superior colliculi, which are involved in controlling the pupillary reflex and eye movements, respectively. The suprachiasmatic nuclei, located in the hypothalamus, are responsible for regulating circadian rhythms and receive input from a subset of ganglion cells that are specialized for detecting changes in ambient light levels.

Question 18

Which one of the following is not an important feature of the LGN's layered structure?
A) eye of origin
B) ganglion cell type
C) topography
D) Photoreceptor type

Accepted Answer

The photoreceptor type is not an important feature of the LGN's layered structure. The LGN receives information from the retina through the optic nerve, but it does not distinguish between different types of photoreceptors (rods or cones) since this information is already combined and processed by the retina. The important features of the LGN's layered structure include the eye of origin (since each layer receives inputs from one eye), ganglion cell type (since different layers receive inputs from different types of ganglion cells), and topography (since neighboring areas of the retina are processed by neighboring areas of the LGN).

Question 19

Which one of the following is not a cell layer in the LGN?
A) Magno.
B) Bipolar.
C) Parvo.
D) Konio.

Accepted Answer

The bipolar cell layer is not a layer in the LGN. The LGN has six layers, consisting of the magnocellular (Magno) layers, parvocellular (Parvo) layers, and koniocellular (Konio) layers.

Question 20

In which visual cortical area are cells grouped according to speed and disparity preference?
A) MT
B) V1
C) V2
D) V3

Accepted Answer

Cells in area MT (middle temporal area) are known to be selective for speed and disparity (binocular disparity refers to the slight difference between the images seen by each eye, which provides the basis for stereoscopic depth perception).

Quiz 7: Visual Physiology

Which one of the following statements about temporal responses is not correct?

Which description of partial decussation is incorrect

Which one of the following is the correct term to describe the process in which a cell is excited when light falls in one part of its receptive field, and inhibited when light falls in another part?

Which one of the following is not associated with the functional architecture of striate cortex (V1) ?

Which statement is correct? Simple cells:

Which one of the following statements about bipolar cells is not correct?

Which of the following terms is the correct name for a class of retinal cell whose axons spread laterally across the retina, making contact with several photoreceptors.

Which area of visual cortex contains the highest proportions of motion and disparity selective cells?

Lesions affecting which visual cortical area usually result in a complete loss of visual function in the affected area?

Beyond striate cortex a number of visually responsive cortical areas have been identified on the basis of several criteria, which one of the following is not one of these criteria?

Cortical cells demonstrate many different forms of stimulus selectivity, which one of these is not associated with striate cortex?

How many layers of cell nuclei does the retina contain?

Which one of the following statements describes the Stiles-Crawford effect?

Which one of the following are not ganglion cells?

Which of the following statements about chromatic opponency is incorrect?

Which ganglion cell class is the most numerous and responds only at high light levels?

Where do approximately 90% of ganglion cell fibres project?

Which one of the following is not an important feature of the LGN's layered structure?

Which one of the following is not a cell layer in the LGN?

In which visual cortical area are cells grouped according to speed and disparity preference?