Sensation and Perception

Question 1

Sensation

Answer 1

~The conversion, or transduction, of physical, electromagnetic, auditory and other information from the internal and external environment into electrical signals in the nervous system.
~This is done by receptors in the PNS.
~The water is hot or cold.

Question 2

Perception

Answer 2

~The processing of sensory information to make sense of its significance.
~Helps us make sense of the world.
~People might perceive hot or cold water differently.

Question 3

Sensory Receptors

Answer 3

~Nerves that respond to stimuli and trigger electrical signals.
~Sensory stimuli are transmitted to projection areas.

Question 4

Sensory Ganglia

Answer 4

~Collections of cell bodies outside the CNS.

Question 5

Photoreceptors

Answer 5

~Respond to electromagnetic waves in the visible spectrum.

~Brightness, color and shape.

Question 6

Hair Cells

Answer 6

Respond to movement of fluid in the inner ear structures.

Question 7

Nociceptors

Answer 7

Respond to painful or noxious stimuli.

Question 8

Thermoreceptors

Answer 8

Respond to changes in temperature.

Question 9

Osmoreceptors

Answer 9

Respond to the osmolarity of the blood.

Question 10

Olfactory Receptors

Answer 10

Respond to volatile compounds.

Question 11

Taste Receptors

Answer 11

Respond to dissolve compounds.

Question 12

Threshold

Answer 12

The minimum stimulus that causes a change in signal transduction.

Question 13

Absolute Threshold

Answer 13

~The minimum intensity at which a stimulus will be transduced (converted into action potentials)
~Minimum stimulus energy that is needed to activate the sensory system.

Question 14

Threshold of Conscious Perception/ Subliminal Perception

Answer 14

~The minimum stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness.

Question 15

Absolute Threshold vs Subliminal Perception

Answer 15

~A stimulus below the absolute threshold will not be transduced and will NOT reach the CNS.
~A stimulus bellow the subliminal perception will arrive to the CNS, but does not reach the part of the brain that controls attention and consciousness.

Question 16

Difference Threshold/ Just-Noticeable Difference

Answer 16

~The minimum difference in magnitude between tow stimuli before one can perceive this difference.

Question 17

Weber’s Law

Answer 17

~Relates to the difference threshold
~The jnd for a stimulus is proportional to the magnitude go this stimulus, and that this is proportion is constant over most of the range of possible stimuli.
~Difference/Original = 0.68
~This appears to be accurate for al sensory modalities, except at the extremely high and low ends of each range.

Question 18

Signal Detection Theory

Answer 18

~Refers to the effects of nonsesnsory factors, such as experiences, motives and expectations, on perception of stimuli.
~Focuses on the change in out perception if the same stimuli depending on both internal (physiological) and external (environmental) context.

Question 19

Response Bias

Answer 19

~Refers to the tendency of subjects to systematically respond to a stimulus in a particular way due to nonsensory factors.
~A significant of false alarms and misses in a signal detection experiment is an indication of response bias.

Question 20

Signal Detection Experiments

Answer 20

~Catch Trials –> The signal is present.
~Noise Trials –> The signal is not present.
~If signal is present and subject’s response is YES then –> Hit.
~If signal is present and subject’s response is NO –> Miss.
~If signal is absent and subject’s response is YES –> False Alarm.
~If signal is absent and subject’s response is NO –> Correct Negative.

Question 21

Adaptation

Answer 21

~Decrease in response to a stimulus over time. Both physiological and psychological component
~Increases the difference threshold.

Question 22

Sclera

Answer 22

The white part of the eye.

Question 23

Choroidal Vessels and Retinal Vessels

Answer 23

They supply the eye with nutrients.

Question 24

Retina

Answer 24

~The innermost layer of the eye.

~Contains photoreceptors that transduce light into electrical information.

Question 25

Cornea

Answer 25

~Light passes first through here. | ~Gathers and focuses the incoming light.

Question 26

Iris

Answer 26

~The colored part of the eye. ~Divides the front of the eye between the anterior and posterior chambers. ~Contains two muscles: dilator papillae and constrictor papillae.

Question 27

Dilator Pupillae

Answer 27

Opens the pupil under sympathetic stimulation

Question 28

Constrictor Pupillae

Answer 28

Constricts the pupil under parasympathetic stimulation.

Question 29

Ciliary Body

Answer 29

Produces aqueous humor that bathes the front part of the eye before draining into the Canal of Sclemm

Question 30

Lens

Answer 30

~Refracts incoming light to focus it on the retina and is help in place by the suspensory ligaments connected to the ciliary muscle. ~Behind this lies the vitreous --> a transparent gel that supports the retina.

Question 31

Ciliary Muscle

Answer 31

~Contraction of this is done under the parasympathetic nervous system. ~When it contracts it pulls on the suspensory ligaments and changes the shape of the lens (accommodation)

Question 32

Retina

Answer 32

~Is in the back of the eye. ~Consists of neural elements and blood vessels. ~Converts incoming photons of light to electrical signals. Considered a part of the CNS ~Contains photoreceptors (duplexity or duplicity theory of vision).

Question 33

Cones

Answer 33

~Comes in three forms (short-, medium- and long-wavelength) to detect colors. ~Senses fine details.

Question 34

Rods

Answer 34

~Senses light and dark due to the fact that they contain rhodopsin. ~More functional in reduced illumination. ~Low sensitive to detail and are not involved in color vision, but permit night vision. ~There are more rods than cones in the human eye.

Question 35

Macula

Answer 35

~The central section fo the retina. | ~high concentration of cones.

Question 36

Fovea

Answer 36

~Contains only cones. ~As you move farther away from the fovea, the concentration of rods increase while the concentration of cones decrease. ~Visual acuity is best here.

Question 37

Bipolar Cells

Answer 37

~Rods and cones connect here. | ~This synapses with ganglion cells.

Question 38

Ganglion Cells

Answer 38

~Each ganglion cell has to represent the combined activity of many rods and cones. ~Cones converging onto an individual ganglion cell is smaller than for rods; therefore, color vision has a greater sensitivity to fine detail.

Question 39

Optic Nerve

Answer 39

~Bipolar + Ganglion cells.

Question 40

Amacrine and Horizontal Cells

Answer 40

~Receive input from multiple retinal cells in the same area before the information is passed on to ganglion cells. ~They are important for edge detection, as they increase our perception of contrast.

Question 41

Visual Pathways

Answer 41

~Optic nerves --> optic chiasm --> optic tract --> LGN (hypothalamus) --> visual radiation (visual cortex). ~The optic chasm contains fibers crossing from the nasal side of the retina (Templar visual fields) of both eyes.

Question 42

Parallel Processing

Answer 42

~The ability to simultaneously analyze and combine information regarding color, shape and motion. Then, these features can be compared to our memories to determine what is being viewed.

Question 43

Color

Answer 43

~Cones are responsible for colored vision.

Question 44

Shape

Answer 44

~Detected by parvocellular cells.

Question 45

Parvocellular Cells

Answer 45

~They have high spatial resolution and low temporal resolution. ~They only work with stationary or slow-moving objects.

Question 46

Motion

Answer 46

~Detected by magnocellular cells.

Question 47

Magnocellular Cells

Answer 47

~They have high temporal resolution and low spatial resolution. ~Provide a blurry but moving image of an object

Question 48

Visual Path

Answer 48

Cornea --> pupil --> lens --> vitreous --> retina(rods and cones --> bipolar cells --> ganglion cells) --> optic nerve --> optic chiasm --> optic tract --> LGN in thalamus --> radiations through parietal temporal lobes -->visual cortex (occipital lobe).

Question 49

Pinna/ Auricle

Answer 49

~Cartilaginous outside part of the year. | ~Channels sound waves into the external auditory canal..

Question 50

External Auditory Canal

Answer 50

Directs the sound waves to the tympanic membrane (eardrum).

Question 51

Tympanic Membrane

Answer 51

~The frequency of the sound waves determines the rate at which the tympanic membrane vibrates. ~High rates for higher frequencies and lower rates for lower frequencies. ~Louder sounds have greater intensity which corresponds to an increased amplitude of this vibration.

Question 52

Ossicle

Answer 52

~Malleus (hammer) ~Incus (anvil) ~Stapes (stirrup)

Question 53

Eustachian Tube

Answer 53

~The middle ear is connected to the nasal activity via this. | ~Helps equalize pressure between the middle ear and the environment.

Question 54

Bony Labyrinth

Answer 54

~Cochlea. ~Vestibule. ~Semicircular Canals. ~They are continuous and are filled with membranous labyrinth (which is based with a potassium-rich fluid called the endolymph).

Question 55

Perilymph

Answer 55

~Helps the membranous labyrinth suspend within the bony labyrinth. ~Transmits vibrations from the outside world and cushions the inner ear structures.

Question 56

Cochlea

Answer 56

~Middle scala --> organ of Corti.

Question 57

Organ of Corti

Answer 57

~Houses the actual hearing apparatus. ~Bathed in endolymph. ~Rests on basilar membrane.

Question 58

Tectorial Membrane

Answer 58

~Relatively immobile membrane | ~On top of the Organ of Corti.

Question 59

Sound Entering the Cochlea

Answer 59

~Sound enters through the Cochlea through the Oval Window and causes vibrations perilymph which are transmitted to the basilar membrane.

Question 60

Round Window

Answer 60

~A membranes covered hole in the cochlea | ~Permits the perilymph to actually move within the cochlea.

Question 61

Hair Cells

Answer 61

~Allow the conversion of physical stimulus to electrical signals. ~Vibrations reach the basilar membrane --> hair cells move in the endolymph --> ion channels opening --> receptor potential

Question 62

Vestibule

Answer 62

~The portion of the bony labyrinth that contains utricle and saccule. ~Linear acceleration (determines one's orientation in 3D space). ~Otoliths --> resist the motion. This bends and stimulates the hair cells.

Question 63

Semicircular Canals

Answer 63

~Rotational Acceleration. ~Are arranged perpendicular to each other. ~Ampulla are swollen ends. ~When the head rotates, endolymph in the semicircular canals resists this motion, bending the underlying hair cells.

Question 64

Auditory Pathways

Answer 64

~Most sound info passes through the vestibulucschler nerve to the brain stem --> MGN of the thalamus --> auditory complex --> Superior Olive (localizes the sound) or Inferior Colliculus (involved in the startle reflex and helps keep the eyes fixed on a point while the head is turned).

Question 65

Place Theory

Answer 65

~States that the location of a hair cell on the basilar membrane determines the perception of pitch when that hair cell is vibrated ~Highest Frequency --> vibrations closed to the oval window ~Lowest Frequency --> causes vibration in the apex (away form the oval window)

Question 66

Smell

Answer 66

~The detection of volatile or aerosolized chemicals by the olfactory chemoreceptors in the olfactory epithelium. ~Olfactory nerves --> Olfactory bulb and olfactory tract --> limbic system. Pheromones are chemicals given off by animals that have an effect on social, foraging, and sexual behavior in other membranes of that species.

Question 67

Taste

Answer 67

~Sweet, sour, salty, bitter and umami (savory). ~Detected by chemoreceptors. ~The detection of dissolved compounds by taste buds in papillae. ~Taste buds --> brainstem --> taste center in the thalamus --> higher-order brain regions.

Question 68

Somatosensation

Answer 68

~Refers to the four touch modalities: pressure, vibration, pain and temperature. ~Pain and temperature use a different pathway than pressure and vibration through the spinal cord.

Question 69

Pacinian Corpuscles

Answer 69

Deep pressure and vibrations.

Question 70

Meissner Corpuscles

Answer 70

Light touch.

Question 71

Merkel Cells

Answer 71

Deep pressure and texture.

Question 72

Ruffini Endings

Answer 72

Stretch

Question 73

Free Nerve Endings

Answer 73

Pain and temperature.

Question 74

Two-Point Threshold

Answer 74

~The minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli. ~This depends on the density of nerves.

Question 75

Physiological Zero

Answer 75

The normal temperature of the skin which objects are compared to determine if they feel "warm" or "cold".

Question 76

Nociceptors

Answer 76

Responsible for pain perception.

Question 77

Gate Theory of Pain

Answer 77

Pain sensation is reduced when others somatosensory signals are present.

Question 78

Kinesthetic Sense

Answer 78

~The ability ti tell where one's body is in 3D space. ~They are mostly found in muscles and joints. ~Plays critical roles in hand-eye coordination, balance and mobility.

Question 79

Bottom-Up Processing

Answer 79

~Data-driven. ~Parallel processing and feature detection. ~Slower, but less prone to mistakes. ~The brain takes the individual sensory stimuli and combines them together to create a cohesive image before determining what the object is.

Question 80

Top-Down Processing

Answer 80

~Conceptually driven. ~Driven by memories and expectations that allow the brain to recognize the whole object and then recognize the components based on these expectations. ~Faster, but its more prone to make mistakes.

Question 81

Perceptual Organization

Answer 81

~Refers to our synthesis of stimuli to make sense of the world, including integration of depth, form, motion and constancy ~Both monocular nd binocular cues. ~Monocular --> size, partial obscuring, convergence of parallel lines at a distance, position and lighting and shadowing. ~Binocular --> slight differences between two images.

Question 82

Form

Answer 82

Determined through parallel processing and feature detection.

Question 83

Constancy

Answer 83

We perceive certain characteristics of objects to remain the same, despite differences in the environment.

Question 84

Gestalt Principles

Answer 84

~Ways that the brain can infer missing parts of a picture when a picture is incomplete. ~Law of proximity, law of similarity, law of good continuation, subjective contours, law of closure and law of pragnanz.

Question 85

Law of Proximity

Answer 85

~The elements close to one another tend to be perceives as a unit.

Question 86

Law of Similarity

Answer 86

~Objects that are similar appear to be grouped together.

Question 87

Law of Good Continuation

Answer 87

~Elements that appear to follow the same pathway tend to be grouped together.

Question 88

Subjective Contours

Answer 88

~The perception of nonexistent edges in figures, based of surrounding visual cues.

Question 89

Law of Closure

Answer 89

~When a space is enclosed by a group of lines, it is perceived a complete or closed line.

Question 90

Law of Pragnanz

Answer 90

~Perceptual organization will always be as regular, simple, and symmetric as possible.