Ch 2 sensation and perception

sensation

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

perception

processing of sensory info to make sense of its significance

sensory receptors

nerves that respond to stimuli and trigger electrical signals

sensory neurons are associated w ______________

sensory ganglia

sensory ganglia

collections of cell bodies outside of the central nervous system

sensory stimuli are transmitted to ___________ in the brain which further analyze the sensory input

projection areas

common sensory receptors include:

• photoreceptors

• hair cells

• nociceptors

• thermoreceptors

• osmoreceptors

• olfactory receptors

• taste receptors

threshold

minimum stimulus that causes a change in signal transduction

absolute threshold

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

threshold of conscious perception

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

difference threshold (just noticeable difference, jnd)

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

Weber’s Law

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

Signal detection theory

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

response bias

signal detection experiment 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

adaptation

refers to a decrease in response to a stimulus over time

eye

organ specialized to detect light in the form of photons

cornea

gathers and filters incoming light

iris

divides the front of the eye into the anterior and posterior chambers it contains two muscles , the dilator and constrictor pupillae which open and close the pupil

what opens and closes the pupil

dilator and constrictor pupillae

lens

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

ciliary body

produces aqueous humor, which drains through the canal of Schl

rods detect

light and dark

cones

come in 2 forms S,M,L wavelenghts to detect color

retina contains mostly cones in____________ which corresponds to _______

macula : central visual field

the center of the macula is the ________ which contains only cones

fovea

rods and cones synapse on ____________- which synapse on ___________

bipolar cells, ganglion cells

integration of the signals from ganglion cells and edge sharpening is performed by ________— and ________—- cells

horizontal and amacrine cells

the bulk of the eye is supported by the ______________ on the inside and the ___________— and ____________ on the outside

vitreous; sclera and choroid

visual pathway

starts from the eye, travels thru optic nerves, optic chiasm, optic tracts, lateral geniculate nucleus (LGN) of the thalamus, and visual radiations to get to the visual cortex

the optic chiasm contains fibers crossing from the _______________- side of the retina (temporal visual fields of both eyes)

nasal side

the visual radiations run through the _____— and _____— lobes

temporal and parietal

the visual cortex is in the _________ lobe

occipital

vision like all senses, is processed thru _________

parallel processing

parallel processing

the ability to simultaneously analyze and combine info regarding color, form, motion, and depthco

color is detected by

cones

form is detected by __________ ___ with high spatial resolution and low temporal resolution

parvocellular cells

motion is detected by _____________ _____—- with low spatial resolution and high temporal resolution

magnocellular cellsd

depth is detected by _________ _________—

binocular neurons

ear is divided into

outer middle and inner

outer ear consists of

pinna (auricle), external auditory canal, and tympanic membrane

middle ear consists of ossicles (3) : ______________ ___________ ___

malleus ( hammer), incus(anvil), and stapes (stirrup)

the footplate of the stapes rests on the ________________ of the cochlea

oval window

the middle ear is connected to the nasal cavity by the _______

EUstachian tube

the inner ear contains the ________________

bony labyrinth within which is the Membranous labyrith

the bony labyrinth is filled with __________

perilymph ,

the membranous labyrinth is filled with _

endolymph

the membranous labyrinth consists of the _________________ …

cochlea, utricle and saccule, and semicircular canals

cochlea does..?

detects sounds

utricle and saccule

detect linear acceleration

semicircular canals

detect rotational acceleration

auditory pathway

starts from the cochlea and travels through the vestibulocochlear nerve and medial geniculate nucleus (MGN) of the thalamus to get to the auditory cortex in the temporal lobe

sound information also projects to the

superior olive, which localizes the sound, and the inferior colliculus which is involved in the startle reflex

sound startle reflex

inferior colliculus

superior olive

localizes the sound

smell

detection of volatile or aerosolized chemicals by the olfactory chemoreceptors (olfactory nerves in the olfactory epithelium)

olfactory pathway

starts from the olfactory nerves and travels thru the olfactory bulb and olfactory tract to get to higher order brain areas such as limbic system

pheromones

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

taste

detection of dissolved compounds by taste buds in papillae. it comes in 5 modalites: sweet, sour, salty, bitter, and umami (savory)

somatosensation

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

4 touch modalities of somatosensation

pressure vibration pain and temp

two point threshold

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

physiological zero

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

nociceptors

responsible for pain perception

gate theory of pain

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

kinesthetic sense (proprioception)

refers to the ability to tell where one’s body is in 3d space

bottom-up data-driven processing

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

top -down (conceptually driven) processing

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

perceptual organization

refers to our synthesis of stimuli to make sense of the world , including depth, form, motion, and constancy

gestalt principles

ways that the brain can infer missing parts of a picture when a picture is incomplete (optical illusion)

law of proximity

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

law of similarity

says that objects that are similar appear to be grouped together

law of good continuation

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

subjective contours

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

law of closure

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

law of pragnanz

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