Test 2

Question 1

What is the retina and why is it important?

Answer 1

It’s the back surface of the eye that is lined with visual receptors and where incoming light hits. It detects photons of light and then fires impulses along optic nerve to the brain

Question 2

In what way does image hit the retina and how do we see it right-side-up?

Answer 2

Light from the left side of the world hits the right side of the retina and vice versa. Light from below strikes the top half. Refraction through a convex lens flips images.

Question 3

Cells in the retina - photoreceptors

Answer 3

Located in the back of the eye. Message bipolar cells.

Question 4

Cells in the retina - bipolar cells

Answer 4

Located close to the center of the eye. Message ganglion cells.

Question 5

Cells in the retina - amacrine cells

Answer 5

Helps ganglion cells respond to certain shapes, directions of movement or other visual features.

Question 6

Cells in the retina - horizontal cells

Answer 6

If light hit one receptor but not the other ones, the horizontal cells inhibits the surrounding receptors for edge detection.

Question 7

Cells in the retina - ganglion cells

Answer 7

Located even closer to the center of the eye.

Question 8

Optic nerve

Answer 8

The bundled axons from ganglion cells that exit the retina.

Question 9

Blind spot

Answer 9

Blind spot is where the optic exit and where blood vessels enter and leave. There are no receptors in this spot. We don’t notice it because 1) your brain fills in the gap, 2) anything in the blind spot in one eye is visible to the other eye.

Question 10

Fovea

Answer 10

A tiny area specialized for acute, detailed vision.

Question 11

Difference between foveal and peripheral vision

Answer 11

Foveal vision: useful in bright lights, but poor in dim lightning. Because there is one ganglion dedicated to each receptor, there is more acuity (better vision for details). Because many cones it’s best for color vision.
Peripheral vision: more rods than cones. One ganglion cell receives input from multiple receptors = lower acuity. Given higher number of rods = it’s good for dim lightning, not for bright light or color vision.

Question 12

Difference between rods and cones

Answer 12

Rods: abundant in the periphery of retina. Responds to faint light but not useful in daylight because bright light bleaches them.
Cones: abundant in and near the fovea. Essential for color vision. Less active in dim light and more useful in bright light.

Question 13

Trichromatic Theory (Young-Helmholtz Theory)

Answer 13

Hypothesized there to be 3 types of photoreceptors in the eye. Each type sensitive to a particular range of visual light. Found that people could match any color by mixing the appropriate amounts of just 3 wavelenghts. The 3 types of cone photoreceptors classified by what wavelenght they responded to. Short-preferring (blue), middle-preferring (green), and long-preferring (red). The relative strenghts of the signals detected by each type was interpreted by the brain as a visible color.

Question 14

Color constancy

Answer 14

Our ability to recognize colors despite changes in lightning. Ex: if you wear green-tinted glasses, a banana will still be yellow for you.

Question 15

Retinex Theory

Answer 15

Says both the eye and the brain are involved in color processing. The brain compares info from various parts of the retina to determine the brightness and color for each area. Our brain uses context to perceive color. A certain wavelenght of light can appear as different colors depending on the background or context. When we see something, we make an inference. Visual perception requires reasoning and inference, not just retinal stimulation.

Question 16

What occurs in red-green color deficiency (protanopia)?

Answer 16

Long and medium wavelenght cones have the same photo-pigment instead of different ones. People with this can’t tell the difference between red and green. This gene is in the X chromosome so it affects more men than women.

Question 17

Photopigments

Answer 17

Chemicals that release energy when struck by light.

Question 18

What is 11-cis-retinal, and what does it convert to? What happens as a result of the conversion of this molecule?

Answer 18

It’s a derivative of vitamin A. Converts to all-trans-retinal. This conversion creates the electrical current that goes to our brain.

Question 19

Opsins

Answer 19

Proteins that bind to 11-cis-retinal and modify its sensitivity to different wavelenghts of light.

Question 20

When light strikes one photoreceptor, what happens to the bipolar cell to which it’s connected? What happens to surrounding bipolar cells? Mention horizontal cells.

Answer 20

When light hits one receptor, it will result in a exitation of its bipolar cell. It also excites a horizontal cell, which inhibits surrounding bipolar cells.

Question 21

Receptive field

Answer 21

A point in visual space from which light strikes the cell and excites or inhibits it.

Question 22

Describe the pathway from the retina to the brain. Discuss optic chiasm.

Answer 22

Ganglion cells’ axons form the optic nerves. The optic nerves from each eye meet at the optic chiasm. Half of the axons from each eye cross to the opposite side of the brain. From the optic chiasm, most of the ganglion cell axons go to the lateral geniculate nucleus.

Question 23

Lateral geniculate nucleus (LGN)

Answer 23

Part of the thalamus. Receives major sensory input from retina and relays it to V1 (primary visual cortex).

Question 24

Two layers of the LGN

Answer 24

Parvocellular: mostly in fovea. Small cell bodies and small receptive fields. Detect visual details and colors. “What” am I seeing?
Magnocellular: throughout retina. Larger cell bodies and receptive fields. Detect movement of large, overall patterns. “Where” am I seeing it?

Question 25

Visual info from the right visual field is processed in the ... occipital lobe, and visual info from the left visual field is processed in the ... occipital lobe.

Answer 25

left. | right.

Question 26

Blindsight

Answer 26

An ability to respond in limited ways to visual info without perceiving it consciously. Can occur among those with damage to V1. 2 possible explanations: 1) some healthy V1 tissue may remain but not enough fto provide conscious perception. 2) the thalamus sends visual input to other brain areas outside of the V1 to respond without conscious awareness of it. Main point: V1 is crusial for conscious visual perception.

Question 27

Cells in visual cortex - simple cells

Answer 27

Respond to exact location of a stimulus. Have receptive fields with fixed excitatory and inhibitory zones. The more light shines on excitatory zone, the more cell activity. The more light shines on inhibitory zone, the less activity.

Question 28

Cells in visual cortex - complex cells

Answer 28

Larger receptive fields. Don't respond to exact location of a stimulus. Will respond to a stimulus equally throughout a large area. Responds to patterns of light in a particular orientation anywhere within its large receptive fields. Responds most strongly to a moving stimulus.

Question 29

Cells in visual cortex - hypercomplex (end-stopped) cells

Answer 29

Resemble complex cells, but have a strong inhibitory area at one end of its receptive field. Responds to a pattern of light anywhere in a broad field; provided the stimulus doesn't extend beyond a certain point.

Question 30

Ventral pathway

Answer 30

The "what" pathway. It's going through the temporal cortex. Specialized for identifying and recognizing objects.

Question 31

Visual agnosia

Answer 31

The inability to recognize objects despite otherwise satisfactory vision. Someone with this can point to the object and describe features, but can't recognize what it is.

Question 32

What type of object does the parahippocampal cortex most strongly respond to?

Answer 32

Places/landscapes

Question 33

What type of object does the fusiform gyrus most strongly respond to?

Answer 33

Faces

Question 34

What does the occipital face area respond most strongly to?

Answer 34

Facial features

Question 35

Prosopagnosia

Answer 35

Impairment in ability to recognize faces. From damage or innate structural/functional differences. When people with this look at a face, they can describe a few features but can't identify the person.

Question 36

Dorsal pathway

Answer 36

The "how" pathway. It goes through the parietal cortex. Important for visually guided movements.

Question 37

Damage to dorsal pathway

Answer 37

They can see objects but can't integrate their vision with movements. Can read/recognize faces, describe objects in detail but can't accurately reach out and grasp the object. May bump into objects. Can tell you what their furniture at home looks like, but can't tell you how it's spatially arranged.

Question 38

Role of middle temporal cortex (MT) and medial superior temporal cortex (MST) play in motion perception

Answer 38

MT: detect acceleration and deceleration and speed in three dimentions. Responds to photographs that imply movement. Electrical stimulation of this area results in seeing movements that doesn't exist. MST: responds if something moves relative to background.

Question 39

Sound Wave

Answer 39

Periodic compressions of air, water, or other media.

Question 40

The Components of Sound Waves

Answer 40

Amplitude: loudness. The intensity of a sound wave. In general, sounds of greater amplitude sound louder. Frequency: the number of compressions/waves/cycles per second. 1 Hz = 1 cycle per second.

Question 41

Speech prosody

Answer 41

People communicate emotions by alternations in pitch, loudness, timbre. Graditude, sarcasm etc. depends on the sound quality produced. Conveying emotional info by tone of voice is prosody.

Question 42

Timbre

Answer 42

the character of a sound. Tone quality or tone complexity.

Question 43

what is the function of the pinna?

Answer 43

Alter the reflections of sound waves to help locate source of sound.

Question 44

how are sound waves transmitted by the tympanic membrane and then carried through the middle ear to the inner ear

Answer 44

Sound waves pass through the auditory canal and strike the tympanic membrane (eardrum). Tympanic membrane vibrates at same frequency as sound waves. Tympanic membrane connects to 3 bones; hammer, anvil, and stirrup. The 3 bones convert sound waves into waves of greater pressure on the oval window. This transformation is important because vibrations in the air can't produce significant vibrations in the viscous fluid behind the oval window.

Question 45

how vibrations at the oval window are transformed into auditory messages to the brain in the cochlea. Mention hair cells

Answer 45

the stapes pushes against the oval window which transmits waves of sound, and the vibrations are sent to the cochlea which is filled with fluid. The cochea consists of tiny hair cells. Hair cells line the cochlea and transmit vibrations into electrical impulses that are carried to the brain by sensory nerves. Hair cells are located in the basilar membrane.

Question 46

What is the method by which our auditory system encodes low-frequency sounds?

Answer 46

Frequency theory: Basilar membrane vibrates in synchrony with a sound, causing auditory nerve axons to produce action potentials at that same frequency.

Question 47

What is the method by which our auditory system encodes sounds of higher frequency?

Answer 47

Volley Theory. Volley principle: groups of neurons of respond by firing action potentials out of phase with one another. When combined, greater frequency of sound is encoded.

Question 48

primary auditory cortex; where is it located

Answer 48

Its primary function is to process sound along with its volume and pitch. The location of the sound is also processed via primary auditory cortex. This auditory cortex is essential to comprehend the spoken language and is concerned with tasks such as finding out and separating the auditory objects. Located in the superior temporal cortex.

Question 49

tonotopic map

Answer 49

The way in which the primary auditory cortex is organized.

Question 50

Describe the following three different ways in which we localize sound - Interaural time difference

Answer 50

when concerning humans or animals, is the difference in arrival time of a sound between two ears. It is important in the localization of sounds, as it provides a cue to the direction or angle of the sound source from the head.

Question 51

Describe the following three different ways in which we localize sound - interaural intensity difference

Answer 51

arises from the fact that, due to the shadowing of the sound wave by the head (sound shadow), a sound coming from a source located to one side of the head will have a higher intensity, or be louder, at the ear nearest the sound source.

Question 52

Describe the following three different ways in which we localize sound - Interaural phase difference

Answer 52

refers to the difference in the phase of a wave that reaches each ear. A sound wave from the side strikes the two ears out of phase.

Question 53

Difference between amusia and perfect pitch

Answer 53

Amusia: The inability to recognize musical tones or to reproduce them. Amusia can be congenital (present at birth) or be acquired sometime later in life (as from brain damage). Tone deafness. Perfect pitch: the ability to recognize the pitch of a note or to produce any given note

Question 54

conductive deafness

Answer 54

Middle ear deafness. From infection or tumorous bone growth. Corrected by surgery or hearing aids. They may accuse others of talking too softly or mumbling.

Question 55

nerve deafness

Answer 55

Inner ear deafness. From damage to cochlea, hair cells, or auditory nerve. Genetic or environmental or can result from loud noices. Often produces tinnitus.

Question 56

McGurk Effect

Answer 56

Our tendency to integrate visual speech into what we "hear".

Question 57

vestibular organ

Answer 57

Sensations from vestibular organ detect the direction of tilt and the amount of acceleration of the head. You use that info automatically for guiding eye movements and maintaining balance.

Question 58

Describe following types of somatosensory receptors - mechanoreceptors

Answer 58

provide info to the brain about touch, pressure, vibration, and skin tension.

Question 59

Describe following types of somatosensory receptors - thermoreceptors

Answer 59

provide info about temperature

Question 60

Describe following types of somatosensory receptors - nociceptors

Answer 60

provide info about potentially damaging stimuli (pain). Ex: sunburn.

Question 61

We have ... cervical spinal nerves, ... thoracic nerves, ... lumbar nerves,... sacral nerves, and ... coccygeal nerves for a total of ... spinal nerves that enter the spinal cord and deliver info to the brain.

Answer 61

``` 8 12 5 5 1 31 ```

Question 62

dermatome

Answer 62

Kind of like a map. | Each spinal nerve connects to a limited area of the body called a dermatome.

Question 63

primary somatosensory cortex

Answer 63

it's located in the parietal lobe.

Question 64

How does the pain and somatosensory information travel in the spinal cord to the brain and how do these pathways differ?

Answer 64

Paths for pain and touch are parallel, but different. Pain crosses immediately in the spinal cord. Touch info travels up the ipsilateral side to the medulla, then crosses. Pain and touch reach neighboring sites in the cerebral cortex.

Question 65

how are physical and emotional pain similar?

Answer 65

they activate the same region of the brain

Question 66

Gate Theory of Pain

Answer 66

A lot of things influence pain. What we expect of pain can influence how much pain we feel. Spinal cord neurons that receive messages from pain receptors also receive input from touch receptors and from axons descending from the brain.

Question 67

Placebo

Answer 67

fake drugs that are taken during double blind studies. some people show favorable responses to placebos, because their brains release endorphins to kill the pain. They believe that they have taken a real drug, so they perceive that the pain has gone away. A drug or other procedure with no pharmacological effects.

Question 68

What naturally occurring neurotransmitter reduces pain? What drugs act on this particular neurotransmitter system?

Answer 68

Endorphins; they interact with opioid receptors in the brain to reduce the perception of pain

Question 69

Olfactory cells

Answer 69

are on the roof of the nasal cavity that contains millions of olfactory sensory neurons, when particles reach the neurons and sends the signals to the brain;

Question 70

Vomeronasal organ (VNO)

Answer 70

Set of receptors located near, but separate from, the olfactory receptors.

Question 71

Pheromones

Answer 71

A chemical substance produced and released into the environment affecting the behavior of others. Important for most mammals, but less so for humans.

Question 72

Evidence of pheromones in humans

Answer 72

Smell of women’s perspiration increases a man’s testosterone levels. Effect is stronger in heterosexual men vs. homosexual men. The smell of men’s perspiration increases release of cortisol (stress hormone) but not sexual arousal.

Question 73

Synesthesia

Answer 73

The experience some people have in which stimulation of one sense evokes a perception of another type of sense as well. Most common: perceiving letters or numbers in certain colors. Can involve any of the senses, ex: - sounds in response to smell - smell in response to touch - feeling something in response to sight

Question 74

Three categories of vertebrate muscle fibers

Answer 74

1) smooth muscles: control the digestive system and other organs 2) skeletal or striated muscles: control movement of the body in relation to the environment 3) cardiac muscles: control the heart

Question 75

neuromuscular junction

Answer 75

the synapse between a motor neuron and a muscle fiber

Question 76

antagonistic muscles

Answer 76

antagonist - flexor muscle. | Muscles only move in one direction. Moving an arm or a leg requires antagonistic muscles

Question 77

Difference between fast-twitch and slow-twitch muscle fibers

Answer 77

Fast twitch fiber: fire rapidly, fatigue rapidly. Best for generating short bursts of strenght or speed, useful for sprinters. Anaerobic = don't use oxygen. short twitch fibers: fire more slowly, less vigorous contractions and no fatigue. Best for marathon runners and endurance sports. Aerobic = uses oxygen.

Question 78

proprioceptor

Answer 78

A receptor that detect position or movement of a body part or a muscle.

Question 79

Describe the two following proprioceptors - muscle spindle

Answer 79

sensory receptors within a muscle that detect when that muscle is stretched

Question 80

Describe the two following proprioceptors - golgi tendon organ

Answer 80

sensory receptor organ that senses changes in muscle tension.

Question 81

ballistic movements

Answer 81

a movement that is executed as a whole. Once initiated, it cannot be altered. Ex: reflex

Question 82

Central pattern generators

Answer 82

Neural mechanisms in the spinal cord that generate rhythmic patterns of motor output.

Question 83

Motor program

Answer 83

Instinctive, non-learned, fixed sequence of movements that is "hard-wired"

Question 84

two areas in brain associated with planning a movement

Answer 84

1) prefrontal cortex: active during a delay before a movement. Considers probable outcomes of possible movements. People with damage to this area exhibit disorganized/non-rational movements/behaviors. Inactive during dreams. 2) posterior parietal cortex

Question 85

Primary motor cortex (M1) - location + role in executing movement

Answer 85

Located in frontal cortex. M1 axons synapse with interneurons in the spinal cord, but some synapse directly with motor neurons that control muscles.

Question 86

Role of posterior parietal cortex in movement

Answer 86

Monitors position of body relative to world.

Question 87

Two areas involved in inhibiting a movement

Answer 87

Prefrontal cortex and basal ganglia

Question 88

Antisaccade task

Answer 88

Involves inhibiting a response and looking in opposite direction. Requires sustained activity in prefrontal cortex and basal ganglia

Question 89

Describe two corticospinal tracts - lateral corticospinal tract

Answer 89

goes from primary motor cortex, surrounding areas and red nucleus. Axons extend from motor cortex to neurons in spinal cord. In the protrusions of the medulla, axons cross. Controls movement in peripheral areas -> ex: hands and feet.

Question 90

Describe two corticospinal tracts - medial corticospinal tract

Answer 90

Axons go to both sides of the spinal cord. Axons go to trunk, more proximal muscles.

Question 91

How does cerebellum help control movement?

Answer 91

Contains more neurons than the rest of the brain combined. It coordinates timing and force of different muscle groups for fluid limb or body movements.

Question 92

Finger-to-nose test

Answer 92

It's used to assess neurological abnormalities with cerebellum. If damage to cerebellum: trouble with initial rapid movement ex: finger misses nose, stops too soon, or goes too far. If damage to cerebellum nuclei: difficulty with the hold segment -> finger reaches front of nose and then wavers.

Question 93

Role of basal ganglia in movement

Answer 93

It's important for spontaneous, self-initiated behaviors

Question 94

Substantia nigra

Answer 94

Gradual loss of neurons in the substantia nigra (a loss of dopamine-releasing axons to the striatum). The striatum ↓ inhibition of the globus pallidus, which then ↑ inhibitory input to the thalamus. Result: slow, weak (less vigorous) voluntary movements.

Question 95

Parkinson's disease

Answer 95

Rigidity, muscle tremors, slow movements and difficulty initiating physical and mental activity. Causes: genetics and environment. More common in farmers/rural dwellers than in urban dwellers. Most likely combination of both genetics and environment. Gradual loss of neurons in the substantia nigra.

Question 96

How does brain stimulation treat Parkinson's?

Answer 96

It may normalize neuronal (brain cell) activity.

Question 97

Huntington's disease

Answer 97

Deterioration of basal ganglia and cerebral cortex, leading to eventual death. Symptoms begin with arm jerks and facial twitches. Tremors spread to other body parts, develop into writhing. Tremors interfere with walking, speech, and other voluntary movements. Causes: genetics. History of drug/alcohol use can increase risk of early onset.