Module 5

Question 1

law of specific nerve energies

Answer 1

whatever excites a particular nerve establishes a special kind of energy unique to that nerve.

the brain somehow interprets the action potentials from the auditory nerve as sounds, those from the olfactory nerve as odors, etc.

Question 2

Pupil

Answer 2

An opening in the centre of the iris where light enters. Focused by the lens and cornea and projected on the retina.

Question 3

Retina

Answer 3

the rear surface of the eye, which is lined with visual receptors. Everything is inverse and flipped on the receptors

Question 4

Lens

Answer 4

Adjustable part of the eye that focuses light

Question 5

Cornea

Answer 5

Non-adjustable part of the eye that focuses light

Question 6

Bipolar cells

Answer 6

type of neuron in the retina that receives input directly from the receptors, send messaged to ganglion cells in the centre of the eye

Question 7

Ganglion Cells

Answer 7

type of neuron in the retina that receives input from the bipolar cells

Question 8

amacrine cells

Answer 8

refine the input to ganglion cells, enabling certain ones to respond mainly to particular shapes, directions of movement, changes in lighting, color, and other visual features

Question 9

Optic Nerve

Answer 9

Ganglion cell axons that exit through the back of the eye and continue to the brain

Question 10

Blind Spot

Answer 10

Area at the back of the retina where the optic nerve exits; it is devoid of receptors. Your brain will fill the gap or filled by the other eye.

Question 11

Fovea

Answer 11

A tiny area specialized for acute detailed vision. Each receptor connects to a single bipolar cell, which connects to a single ganglion cell

Question 12

Midget Ganglion Cells

Answer 12

ganglion cells in the fovea that respond to a single cone. Provide 70% of visual input to the brain

Question 13

Rods

Answer 13

Type of retinal receptor in the periphery of the retina that detects brightness of light. Not useful in daylight because bright light bleaches them. More rods than cones 20:1

Question 14

Cones

Answer 14

Type of retinal receptor in and near the fovea that contributes to coluor perception. Less active in dim light and more useful in bight light. Provides 90% of brain’s input.

Question 15

Photopigments

Answer 15

chemicals that release energy when struck by light

Question 16

Trichromatic theory/Young-Helmholtz theory

Answer 16

theory that color is perceived through the relative rates of response by three kinds of cones, each one maximally sensitive to a different set of wavelengths

Question 17

Wavelengths

Answer 17

Each cone responds to a some wavelengths (short, medium or long) more than others. Each wavelength corresponds to different colours. Long (red) and medium (yellow) wavelength cones are more abundant than short-wavelength cones (blue).

Question 18

Visual Field

Answer 18

Area of the world that an individual can see at one time

Question 19

Negative colour afterimage

Answer 19

result of staring at a colored object for a prolonged length of time and then looking at a white surface

Question 20

Opponent-Process Theory

Answer 20

We perceive color in terms of opposites. After you stare at one color in one location long enough, you fatigue that response and swing to the opposite

Question 21

Colour Constancy

Answer 21

the ability to recognize colors despite changes in lighting. Your brain compares the color of one object with the color of another

Question 22

Retinex Theory

Answer 22

concept that the cortex compares information from various parts of the retina to determine the brightness and color for each area

Question 23

Colour Vision Deficiency

Answer 23

Impaired ability to perceive color differences. Colour is in the brain, not in the light/object. Many animals have 4 types of cones, making all humans colour deficient. Red-Green colour deficiency is a gene on the X chromosome

Question 24

Horizontal Cells

Answer 24

type of cell that receives input from receptors and delivers inhibitory input to bipolar cells

Question 25

lateral geniculate nucleus

Answer 25

Part of the thalamus that receives incoming visual information from the ganglion cells

Question 26

Receptive Field

Answer 26

The area in visual space that excites or inhibits any neuron. The receptive field of a rod or cone is simply the point in space from which light strikes the cell. Rod/Cone has a small receptive field. Bipolar cell has a receptive field equal to the sum of all the rods and cones that connect to it. Ganglion has a larger receptive field equal to all the bipolar cells that attach to it

Question 26

Lateral Inhibition

Answer 26

The reduction of activity in one neuron by activity in neighboring neurons. The retina’s way of sharpening contrasts to emphasize the borders of objects to heighten the contrast between an illuminated area and its darker surround

Question 27

Parvocellular neurons

Answer 27

Small cell bodies with small receptive fields in or near the fovea. Well suited to detect visual details and colour.

Question 28

Magnocellular neurons

Answer 28

Large cell bodies with large receptive fields that are distributed evenly throughout the retina. Respond strongly to movement and large overall patterns

Question 29

Koniocellular neurons

Answer 29

Small ganglion cells that occur throughout the retina. Have several functions, and their axons terminate in several locations

Question 30

Primary visual cortex/ Area V1

Answer 30

Area of the occipital cortex responsible for the first stage of visual processing. People with damage to area V1 report no conscious vision, no visual imagery, and no visual images in their dreams.

Question 31

blindsight

Answer 31

The ability to respond in limited ways to visual information without perceiving it consciously

Question 32

Simple Cell

Answer 32

Type of visual cortex cell that has a receptive field with fixed excitatory and inhibitory zones. The more light shines in the excitatory zone, the more the cell responds. The more light shines in the inhibitory zone, the less the cell responds

Question 33

Complex Cells

Answer 33

Type of visual cortex cell located in areas V1 and V2 that responds to a pattern of light in a particular orientation anywhere within its large receptive field. Respond most strongly to a stimulus moving in a particular direction

Question 34

End-Stopped Cells or Hypercomplex Cells

Answer 34

Like a complex cell except it is a visual cortex cells that respond to a bar-shaped pattern of light in a particular orientation, but only if it does not extend beyond a certain point

Question 35

feature detectors

Answer 35

Neurons whose responses indicate the presence of a particular feature. Excitation of feature detectors is not sufficient to explain all of vision, as brain’s response to any visual stimulus depends on your expectations as well as on the stimulus itself

Question 36

Sensitive period

Answer 36

time early in development when experiences have a particularly strong and enduring influence

Question 37

Retinal Disparity

Answer 37

the discrepancy between what the left and right eyes see. Needed for stereoscopic depth perception,

Question 38

Strabismus

Answer 38

A condition in which the eyes do not point in the same direction. A promising therapy for lazy eye is to ask a child to play three-dimensional action video games that require attention to both eyes

Question 39

astigmatism

Answer 39

a decreased responsiveness to one direction of line or another, caused by an asymmetric curvature of the eyes. In 70% of infants and 10% of 4 year olds

Question 40

secondary visual cortex (area V2)

Answer 40

area of the brain that processes information from the primary visual cortex (V1) and transmits it to additional areas

Question 41

ventral stream

Answer 41

Visual paths in the temporal cortex that are specialized for identifying and recognizing objects; the “what” path. People with temporal lobe damage can use vision to guide their actions, but they cannot identify what the objects are

Question 42

dorsal stream

Answer 42

Visual path in the parietal cortex that helps the motor system locate objects; the “where” path. They see objects but they don’t integrate their vision well with their arm and leg movements

Question 43

inferior temporal cortex

Answer 43

portion of the cortex where neurons are highly sensitive to complex aspects of the shape of visual stimuli within very large receptive fields. Recognizes meaningful objects, such as an object from any angle.

Question 44

Visual agnosia

Answer 44

An inability to recognize objects despite otherwise satisfactory vision. Common result from damage in the temporal cortex

Question 45

fusiform gyrus

Answer 45

Brain area of the inferior temporal cortex that recognizes faces. Responds strongly to a face viewed from any angle, as well as line drawings and anything else that looks like a face

Question 46

prosopagnosia

Answer 46

the inability to recognize faces due to damage of several brain areas

Question 47

MT or V5

Answer 47

Area of the middle temporal lobe that is important for perception of visual motion. Receive input mostly from the magnocellular path. MT cells detect acceleration or deceleration as well as the absolute speed

Question 48

MST

Answer 48

(medial superior temporal cortex), temporal cortex area that responds best to the expansion, contraction, or rotation of a visual display. Receives input mostly from the magnocellular path. Responds to the expansion, contraction, or rotation of a large visual scene

Question 49

motion blindness

Answer 49

being able to see objects but unable to see whether they are moving or, if so, which direction and how fast

Question 50

saccades

Answer 50

voluntary eye movements