Sensation and perception

Question 1

Define sensation.

Answer 1

The detection of external stimuli and the transmission of this information to the brain.

Question 2

Define perception.

Answer 2

The interpretation of sensory signals.

Question 3

What is the difference between bottom-up processing and top-down processing?

Answer 3

Bottom-up = perception based on physical features of the stimulus.
Top-down = how knowledge, expectations, or experience shape perception

Question 4

What is sensory coding?

Answer 4

Translating the physical properties of stimuli into patterns of neural impulses.

Question 5

What is transduction?

Answer 5

The process by which sensory stimuli are converted to signals the brain can interpret.

Question 6

How does neural firing differ when it comes to qualitative information and quantitative information?

Answer 6

Qualitative - firing in different combinations

Quantitative - firing in different rates

Question 7

What is the absolute threshold? (!not activation)

Answer 7

The minimum intensity of stimulation that must occur before you experience a sensation.

Question 8

What is the difference threshold?

Answer 8

The minimum amount of change that must occur for you to notice the difference between 2 stimuli.
-Just noticeable difference.
(!the more intense the stimulus, the larger the difference threshold)

Question 9

Explain the idea behind the signal detection theory.

Answer 9

A theory of perception based on the idea that detection of a stimulus requires a judgement - it is not all-or-nothing process

• there are always competing stimuli
  - outside (amplitude)
  - inside (mood, attention, motivation, experience)

Question 10

Explain sensory adaptation.

Answer 10

A decrease in sensitivity to a constant level of stimulation.

Question 11

How is the perceptual phenomenon that enables you to “hear colors” or “see music”?

Answer 11

Synesthesia.

Question 12

What are the stimuli, receptors and pathway to brain for vision?

Answer 12

Light waves, rods + cones, optic nerve.

Question 13

What are the stimuli, receptors and pathway to brain for hearing?

Answer 13

Sound waves, hair cells, auditory nerve

Question 14

What are the stimuli, receptors and pathway to brain for taste?

Answer 14

Molecules dissolved on the tongue, taste receptors in taste buds, cranial nerves (facial, glossopharyngeal, vagus nerves)

Question 15

What are the stimuli, receptors and pathway to brain for smell?

Answer 15

Molecules dissolved on the membranes in nose, olfactory receptors, olfactory nerve.

Question 16

What are the stimuli, receptors and pathway to brain for touch?

Answer 16

Pressure on the skin, sensitive ends of touch neurons in skin, cranial nerves - above neck + spinal nerves - the rest of the body.

Question 17

Which part of eye contains rods and cones?

Answer 17

Retina.

Question 18

What is the function of rods + cones?

Answer 18

Transduce light into neural signals.

Question 19

Describe the function of rods.

Answer 19

Retinal cells that respond to low levels of light and result in black and white perception.

Question 20

Describe the function of cones.

Answer 20

Retinal cells that respond to higher levels of light and result in color perception.
-3 types - determine how we see color

Question 21

Which part of retina contains densely packed cones?

Answer 21

Fovea.

Question 22

What is the function of lens in the eye?

Answer 22

Focuses light waves on retina.

• closer—thickens
• further—flattens

Question 23

What is the function of ganglion cells in the eye?

Answer 23

Ganglion cells receive signals from rods + cones (receptors) and generate action potentials that are sent to the brain by the optic nerve.
(receptors do not have axons)

Question 24

What is the optic chiasm?

Answer 24

A place where each optic nerve splits, and half of its fibers cross over to the other side.

Question 25

Explain the theory that proposes that visual areas beyond the primary visual cortex form 2 parallel processing streams. (two pathways)

Answer 25

“What” and “Where” pathways.
Ventral stream = perception and recognition of objects (what)
Dorsal stream = spatial perception (where)

Question 26

Which condition results from the damage of the ventral (“what”) stream?

Answer 26

Agnosia.

Question 27

What does the trichromatic theory propose?

Answer 27

That color vision results from activity of three types of cones.

Question 28

Name and explain the 5 Gestalt perceptual grouping rules.

Answer 28

Proximity - the closer 2 objects are next to each other, the more likely we are to group them together

Similarity - grouping figures according to how closely they resemble each other

Continuity - grouping together contours with the same orientation

Closure - completing figures that have gaps

Illusory contours - perceiving contours when they do not exist

Question 29

Which part of the brain is responsible for recognizing faces and what is the medical term for face blindness?

Answer 29

Fusiform gyrus, prosopagnosia.

Question 30

What is binocular disparity?

Answer 30

It is caused by the distance between 2 eyes. Brain uses the disparity to compute distances to nearby objects.

Question 31

Stereoscopic vision:

Answer 31

The ability to determine an objects depth based on projection to each eye.

Question 32

Explain the term convergence.

Answer 32

A cue to binocular depth perception. When a person views a nearby object, the eye muscles turn the eyes inward.

Question 33

Explain object constancy.

Answer 33

Correctly perceiving objects as constant in their shape, size, color,… despite raw sensory data that could mislead perception.

Question 34

Describe the process of perceiving sound.

Answer 34

Sound waves—-eardrum vibrates—-ossicles + oval window vibrate—-cochlea—-pressure waves in cochlea move the basilar membrane—stimulation of sensory receptors—-hair cells convert the pressure waves into signals that are sent to the brain via auditory nerve—-thalamus—-primary visual cortex

Question 35

Temporal coding vs place coding:

Answer 35

Temporal coding - encoding low-frequency auditory stimuli, firing rates of hair cells match the frequency of the sound wave

Place

Question 36

Temporal coding vs place coding:

Answer 36

Temporal coding - encoding low-frequency auditory stimuli, firing rates of hair cells match the frequency of the sound wave

Place coding - encoding high-frequency stimuli, frequency of the sound is encoded by the location of the hair cells along the basilar membrane.

Question 37

Describe what are the taste buds.

Answer 37

Sensory organs in the mouth that contain the receptors for taste.

Question 38

What is the olfactory epithelium?

Answer 38

A thin layer of tissue within the nasal cavity, that contains the receptors for smell.

Question 39

What is the olfactory bulb?

Answer 39

The brain center for smell, located bellow the frontal lobes.

Question 40

Describe the process of perceiving smell.

Answer 40

Odorants—nasal cavity—olfactory epithelium—olfactory receptors—olfactory bulb—olfactory nerve—areas of the cortex and amygdala

Question 41

What is the difference between haptic sense and kinesthetic sense?

Answer 41

Haptic sense - the sense of touch (temperature, pressure, pain)
Kinesthetic sense - perception of the position in space and movements of our bodies and limbs

Question 42

Anything that makes contact with our skin provides ____ stimulation.

Answer 42

tactile

Question 43

How do the fast and slow nerve fibers for pain differ?

Answer 43

myelination/non-myelination of axons

Question 44

Explain the Gate control theory.

Answer 44

Neural “gates” in the spinal cord allow signals through. Those gates can be closed when other information is being transmitted. (touch, distraction, mood,..)