Mcat Behavioral Sciences (Chapter 2)

Front 1

sensation

Back 1

conversion, or transduction, of physical, electromagnetic, auditory, and other information from the internal and external environment into electrical signals in the nervous system

Front 2

perception

Back 2

the processing of sensory information to make sense of its significance

Front 3

sensory receptors

Back 3

nerves that respond to stimuli and trigger electrical signals

Front 4

sensory ganglia

Back 4

collections of cell bodies outside the central nervous system; associated with sensory neurons

Front 5

projection areas

Back 5

located in the brain; sensory stimuli are transmitted there for further analysis of the sensory input

Front 6

common sensory receptors

Back 6

photoreceptors, hair cells, nocireceptors, thermoreceptors, osmoreceptors, olfactory receptors and taste receptors

Front 7

threshold

Back 7

minimum stimulus that causes a change in signal transduction

Front 8

absolute threshold

Back 8

minimum of stimulus energy that is needed to activate a sensory system

Front 9

threshold of conscious perception

Back 9

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

Front 10

difference threshold or just-noticeable difference (jnd)

Back 10

minimum difference in magnitude between two stimuli before one can perceive this difference

Front 11

Weber's law

Back 11

states that the jnd for a stimulus is proportional to the magnitude of the stimulus, and that this proportion is constant over most of the range of possible stimuli

Front 12

signal detection theory

Back 12

refers to the effects of nonsensory factors, such as experiences, motives, and expectations, on perception of stimuli;

Front 13

signal detection experiments

Back 13

allow us to look at response bias; a stimulus may or may not be given and the subject is asked to state whether or not the stimulus was given; there are four possible outcomes: hits, misses, false alarms, or correct negatives

Front 14

adaptation

Back 14

refers to a decrease in response to a stimulus over time

Front 15

cornea

Back 15

gathers and filters incoming light

Front 16

iris

Back 16

divides the front of the into the anterior and posterior chamber; contains two muscles, the dilator and constrictor pupillae, which open and close the pupil

Front 17

lens

Back 17

refracts incoming light to focus it on the retina and is held in place by suspensory ligaments connected to the ciliary muscle

Front 18

aqueous humor

Back 18

produced by the ciliary body; drains through the canal of Schlemm

Front 19

rods

Back 19

detect light and dark

Front 20

cones

Back 20

come in three forms (short-, medium, and long-wavelength) to detect color

Front 21

macula

Back 21

part of the retina which contains mostly cones; corresponds to the central visual fields

Front 22

fovea

Back 22

the center of the macula; contains cones only

Front 23

bipolar cells

Back 23

what rods and cones synapse on, which in turn synapse on ganglion cells

Front 24

horizontal and amacrine cells

Back 24

integrate signals from ganglion cells and perform edge-sharpening

Front 25

vitreous

Back 25

supports the bulk of the eye on the inside

Front 26

sclera and choroid

Back 26

support the bulk of the eye on the outside

Front 27

visual pathway

Back 27

eye --> optic nerve --> optic chiasm --> optic tract --> optic tract --> lateral geniculate nucleus (LGN) of the thalamus --> visual radiations --> visual cortex

Front 28

optic chiasm

Back 28

contains fibers crossing from the nasal side of the retina (temporal visual fields) of both eyes

Front 29

visual radiations

Back 29

run through the temporal and parietal lobes

Front 30

visual cortex

Back 30

located in the occipital lobe

Front 31

parvocellular cells

Back 31

detect shape; high spatial resolution and low temporal resolution

Front 32

magnocellular cells

Back 32

detect motion; low spatial resolution and high temporal resolution

Front 33

outer ear

Back 33

consists of the pinna (auricle), external auditory canal and tympanic membrane

Front 34

middle ear

Back 34

consists of the ossicles: malleus (hammer), incus (anvil) and stapes (stirrup); the footplate of the stapes rests in the oval window of the cochlea; the middle ear is connected to the nasal cavity by the Eustachian tube

Front 35

inner ear

Back 35

contains the bony labyrinth, within which is the membraneous labyrinth; the bony labyrinth is filled with perilymph; the membranous labyrinth is filled with endolymph and consists of the cochlea, which detects sound; utricle and saccule, which detect linear acceleration; and semicircular canals, which detect rotational acceleration

Front 36

auditory pathway

Back 36

cochlea --> vestibulocochlear nerve --> medial geniculate nucleus (MGN) of the thalamus --> auditory cortex in temporal lobe

Front 37

superior olive

Back 37

another location where sound information is projected; localizes the sound

Front 38

inferior colliculus

Back 38

another location where sound information is projected; involved in the startle reflex

Front 39

olfactory chemoreceptors (olfactory nerves)

Back 39

located in the olfactory epithelium; detect volatile or aerosolized chemicals

Front 40

olfactory pathway

Back 40

olfactory nerves --> olfactory bulb --> olfactory tract --> limbic system

Front 41

pheromones

Back 41

chemicals given off by animals that have an effect on social, foraging, and sexual behavior in other members of that specie

Front 42

taste

Back 42

detection of dissolved compounds by taste buds in papillae; comes in five modalities: sweet, sour, salty, bitter and umami (savory)

Front 43

somatosensation

Back 43

refers to the four touch modalities: pressure, vibration, pain and temperature

Front 44

two-point threshold

Back 44

minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli

Front 45

physiological zero

Back 45

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

Front 46

nociceptors

Back 46

responsible for pain perception

Front 47

gate theory of pain

Back 47

states that pain sensation is reduced when other somatosensory signals are present

Front 48

kinesthetic sense (proprioception)

Back 48

refers to the ability to tell where one's body is in three-dimensional space

Front 49

bottom-up (data-driven) processing

Back 49

refers to recognition of objects by parallel processing and feature detection; it is slower but less prone to mistakes

Front 50

top-down (conceptually driven) processing

Back 50

refers to recognition of an object by memories and expectations, with little attention to detail; it is faster, but more prone to mistakes

Front 51

Gestalt principles

Back 51

ways that the brain can infer missing parts of a picture when a picture is incomplete

Front 52

law of proximity

Back 52

says that elements close to one another tend to be perceived as a unit

Front 53

law of similarity

Back 53

says that objects that are similar appear to be grouped together

Front 54

law of good continuation

Back 54

says that elements that appear to follow the same pathway tend to be grouped together

Front 55

subjective contours

Back 55

refers to the perception of nonexistent edges in figures, based on surrounding visual cues

Front 56

law of closure

Back 56

says that when a space is enclosed by a group of lines, it is perceived as a complete or closed line

Front 57

law of pragnanz

Back 57

says that perceptual organization will always be as regular, simple and symmetric as possible