Neural Coding of Visual Signals

Question 1

In regards to neural coding of visual signals how many systems are there and what are their names?

Answer 1

1. ) Vertical System

2. ) Horizontal System

Question 2

Vertical system involves what?

Answer 2

Signals passing from receptors to bipolar cells to ganglion cells

Question 3

Horizontal system involves what?

Answer 3

Horizontal and amercine cells provide lateral interactions (lateral inhibition) between the different vertical system components

Question 4

What is the function of the ganglion cells?

Answer 4

They serve as the final stage of retinal processing, and transmit info to subcortical visual centers in the brain

Question 5

Axons of Ganglion cells form what?

Answer 5

the optic nerve

Question 6

The receptive field (RF) of a ganglion cell is defined as…

Answer 6

that area in visual space which, upon illumination, influences the signaling of that neuron

Question 7

Sustained ganglion cells are defined as what?

Answer 7

Cells that respond as long as the stimulus remains within the receptive field

Question 8

Transient ganglion cells are defined as what?

Answer 8

Cells that only respond when light is turned on or off

Question 9

M-cells (large ganglion cells) are primarily concerned with what?

Answer 9

Signalling changes of scene, such as movement and changes of light and dark contrast

Question 10

P-cells (small ganglion cells) are primarily concerned with what?

Answer 10

Fine detail, high resolution analysis of an image, and color

Question 11

Define Hemifield, and where the level of separation occurs?

Answer 11

The visual field can be divided by a vertical line, each half of the brain receives info only from OPPOSITE (contralateral) hemifield.
—-Seperation occurs at optic chiasm

Question 12

Images of the visual world are composed of information from two eyes (________), which are merged to form a single image (_______)

Answer 12

Binocularity and Homonymity

Question 13

Homonymous means what? and visually describes what?

Answer 13

Corresponding halves

• –both eyes viewing the same or corresponding visual field.
• **Ex. The upper visual field of the right eye corresponds to the upper visual field of the left eye

Question 14

The right primary visual cortex (area 17) is perceiving only the ____ half of the visual field? ***What is this idea called?

Answer 14

Left

—Contralateral homonymous perception

Question 15

The visual pathway organization is such that everything caudal to the optic chiasm is carrying _____

Answer 15

Only contralateral homonymous sensation

Question 16

Define Anopia, and Hemianopia?

Answer 16

Anopia- loss of visual perception

Hemianopia- los of visual perception of half of the entire visual field