Exam 2: The Visual System

Question 1

Sensation

Answer 1

Detection of stimuli from the environment. ​

Question 2

Perception

Answer 2

Interpretation of detected stimuli. ​

Question 3

Light

Answer 3

Electromagnetic radiation that is visible to the human eye and serves as the primary stimulus for vision.

Question 4

Photon

Answer 4

Elementary particle of light. ​

Question 5

Cornea

Answer 5

The front-most part of the eye that refracts light. ​

Question 6

Pupil

Answer 6

The hole in the center of the eye that allows light to enter. ​

Question 7

Lens

Answer 7

The structure that refracts light to focus it on the retina. ​

Question 8

Accommodation

Answer 8

The process by which the lens changes shape to focus on objects at different distances. ​

Question 9

Retina

Answer 9

The back part of the eye where light is converted into neural signals. ​

Question 10

Fovea

Answer 10

The small pit in the retina with the highest visual acuity. ​

Question 11

Optic Disk

Answer 11

The spot where the optic nerve exits the eye, creating a blind spot. ​

Question 12

Blind spot

Answer 12

The area of the retina where the optic nerve exits the eye, lacking photoreceptors and thus insensitive to light.

Question 13

Photoreceptors

Answer 13

Cells in the retina that detect light (includes rods and cones). ​

Question 14

Rods

Answer 14

Photoreceptors that detect low light levels and are responsible for peripheral vision. ​

Question 15

Cones

Answer 15

Photoreceptors responsible for high-acuity and color vision. ​

Question 16

Phototransduction

Answer 16

The process by which photoreceptors convert light into neural signals. ​

Question 17

Horizontal Cells

Answer 17

Interneurons in the retina that inhibit adjacent photoreceptors. ​

Question 18

Bipolar Cells

Answer 18

Neurons in the retina that receive input from photoreceptors and send signals to ganglion cells. ​

Question 19

Amacrine Cells

Answer 19

Interneurons in the retina that modulate signals between bipolar and ganglion cells. ​

Question 20

Vertical communication in the retina

Answer 20

The flow of visual information from photoreceptors to bipolar cells and then to ganglion cells.

Question 21

Lateral communication in the retina

Answer 21

The processing of visual information across the retina via horizontal and amacrine cells, which modify signals through inhibition and integration.

Question 22

Retinal Ganglion Cells ​

Answer 22

Neurons that receive input from bipolar cells and form the optic nerve. ​

Question 23

Optic Nerve

Answer 23

The nerve that carries visual information from the retina to the brain. ​

Question 24

Optic Chiasm

Answer 24

The point where the optic nerves cross and diverge to the brain. ​

Question 25

Lateral Geniculate Nucleus (LGN) ​

Answer 25

A part of the thalamus that processes visual information from the optic nerve. ​

Question 26

Optic Radiations

Answer 26

Axonal bundles that carry visual information from the LGN to the visual cortex. ​

Question 27

Primary Visual Cortex (V1) ​

Answer 27

The region of the brain that receives and processes visual information. ​

Question 28

Retinotopic Organization

Answer 28

The mapping of visual input from the retina to neurons in the visual cortex. ​

Question 29

Dorsal Stream

Answer 29

The "where" pathway that processes spatial location and movement. ​

Question 30

Ventral Stream

Answer 30

The "what" pathway that processes object identification and visual memory. ​

Question 31

Color Vision Deficiency ​

Answer 31

A condition where one or more types of cone photoreceptors are dysfunctional. ​

Question 32

Saccades

Answer 32

Rapid, jerking movements of the eyes to scan the visual field. ​

Question 33

Convergence

Answer 33

The process by which multiple photoreceptors synapse onto a single bipolar or ganglion cell, affecting visual acuity and sensitivity.

Question 34

Depolarization of photoreceptors

Answer 34

Occurs in the dark when photoreceptors release glutamate due to the open sodium channels in their membranes.

Question 35

Hyperpolarization of photoreceptors

Answer 35

Occurs in response to light when sodium channels close, reducing glutamate release and initiating visual signaling.

Question 36

Three types of cones

Answer 36

The three photoreceptor types in the retina—S-cones (blue), M-cones (green), and L-cones (red)—each sensitive to different wavelengths of light.

Question 37

Receptive field

Answer 37

The specific area of the visual field that influences the activity of a particular neuron in the visual system.

Question 38

Off-center bipolar cells

Answer 38

Bipolar cells that are inhibited by light in the center of their receptive field and excited by light in the surround.

Question 39

On-center bipolar cells

Answer 39

Bipolar cells that are excited by light in the center of their receptive field and inhibited by light in the surround.

Question 40

Edge detection

Answer 40

A fundamental process in visual perception that enhances contrast at borders, crucial for identifying object boundaries.

Question 41

Lateral inhibition

Answer 41

A neural mechanism in which active neurons inhibit neighboring neurons to enhance contrast and sharpen edges in visual processing.

Question 42

Opponent Color Processing

Answer 42

A theory of color vision stating that colors are perceived in opposing pairs (red-green, blue-yellow, black-white) due to retinal and neural processing.

Question 43

Color afterimage

Answer 43

A visual illusion where exposure to a color causes a subsequent complementary color to appear when looking at a neutral surface.

Question 44

Optic tracts

Answer 44

The nerve pathways that extend from the optic chiasm to various visual processing centers, including the thalamus and midbrain.

Question 45

The thalamus

Answer 45

A brain structure that relays and processes sensory information, including visual input from the retina via the lateral geniculate nucleus (LGN).

Question 46

Superior Colliculus

Answer 46

A midbrain structure involved in the coordination of eye movements, visual attention, and orientation toward stimuli.

Question 47

Pretectal Area

Answer 47

A region of the midbrain that plays a role in controlling the pupillary light reflex.

Question 48

Suprachiasmatic Nucleus (SCN)

Answer 48

A region of the hypothalamus that regulates circadian rhythms using light information received from the retina.

Question 49

Secondary (Extrastriate) Visual Areas

Answer 49

Cortical regions beyond the primary visual cortex (V1) that process complex aspects of vision, such as motion (MT/V5) and object recognition.

Question 50

Fusiform face area (FFA)

Answer 50

A region in the inferior temporal cortex specialized for recognizing faces and facial features.

Question 51

Prosopagnosia

Answer 51

A neurological condition, also known as face blindness, in which individuals have difficulty recognizing faces.

Question 52

Visual agnosia

Answer 52

A disorder in which individuals can see objects but cannot recognize or name them due to damage in higher visual processing areas.

Question 53

Optic ataxia

Answer 53

A condition where individuals have difficulty reaching for objects under visual guidance due to damage in the dorsal stream of the visual pathway.

Question 54

Blindsight

Answer 54

A phenomenon in which individuals with damage to the primary visual cortex can respond to visual stimuli without conscious awareness of seeing them.