Psych unit 2.2

Sensation

Process of attneding to and taking in stimuli from enviorment

Perception

Interpretation and organization of incoming sensory information

Psychphysics

Examination of the limits between physcial stimuli in the world ad psychological experience of those stimuli

Absolute Threshold

Minimum amonut of stimuli a person can detect at least 50% of the time

Difference Threshold

The smalles difference in stimuli someone can detect 50% of the time

Webers law

As the size of the stimulus increases, so must the size of the change in order to be detected

Signal detection theory

Sensory Adaptation

• Receptors for any particular sense becomes less responsive in the presence of prolonged and continued stimulus

• You get used to stimulus, so you can not notice it unless it increases

Habituation

• We can gradually get used to a startling or sudden information in our enviorment, even if it isn’t consistent

• Even when you gradually get used to it, it can still capture your attention

McGurk effect

Vision may trump other senses

Cornea

• Where all incoming visual information must pass through

• Protective bulge that covers front of eye

• Works with eyelashes and blinking to keep enviormental debris out of eye

• Think of a corn maze, and how it covers everything inside because its so tall

Pupil

• Just behind cornea

• A hole that allows light into eye

• contracts and expands according to amount of light in enviorment

• Pupil gets Petit in Photons

Iris

• Colored portion of eye

• muscle surrounding eye

• allows pupil ot constrict or contract

• Iris from cross country = strong = muscles = colored hair

Lens

• Focusing info in the form of lifht to the retina, where the viusal receptors are located

• Uses accomodation

  • When lens get thicker or thinner

• Uses accomodation to focus incoming light rays into a sharp image on the retina

Retina

• Light receptive surface lining in the back of the eye

Rods

• Located in Retina

• More numbers than cones

• Specialized for black/white, light/dark vision

• Think of how metal rods have no color

Cones

• Specialized for color vision

• Visual clarity or acuity in daylight hours

• clustered in fovea

  • focal bullseye at center of retina

  • image must fall close to this for us to see color

  • behind the lens

• Think of how colorful a traffic cone it

Nearsightedness

• Focuses incoming message to quick before it reaches retina

• Leads you to be able to see images nearby, but not far

Farsightedness

• Lens may not be accomodatinf soon enough

  • It’s bending to send incoming visual messages onto retina

• Can’t see near stuff

Transduction

• Sensory receptor changes the energy of a physical stimulus into electrical information

  • electrical info is then interpredted by breain

• completed in bipolar and ganglion cell

• Electric info from transduction is sne to bipolar cells and the ganglion cell

Optic nerve

• Made up of oxons of ganglion cells

• Where newly tranduced message is carried to thalamus abd eventually visual cortex in occipital lobe

Blind spot

• Point where optic nerve exits retina in order to carry messages to the brain

• no rods or cones to process stimuli

• Image in this area cannot be seen

Dark adaptation

• Process by which our rods become fully functional in a dark room

  • takes 20 minutes

• Only takes our cones a couple of minutes

Trichromatic theory of color

• there are 3 different types of color regulators (cones)

  • each are specialized in either red, green, or blue

• When these colors are combined, we can see all colors of light

• Equal amounts of red, green, and blue create white

  • color is reflected

  • additive color mixing

• Red, blue, and yellow make black/brown

  • subtractive color mixing

  • light is absorbed

Color blindness

• Complete CB is rare

• Color deficing is more accurate

• see some colors, but struggle to differentiate between them

• most common is red-green CB

  • red and green both look like brown

Opponent process theory

• 2 pairs of cones

  • 1 responds to red and green while 1 responds to blue and yellow

  • each paur works opposite to other

  • when one is excited, the other is inhibited

Afterimage

• Visual illusion or perspual experience that continues to appear in the eye or mind even after the original light or stimulus has been removed

What are the 3 major divisions of the ear

• Outer ear

• Middle Ear

• Inner Ear

Outer Ear

• Conatins auditory canal

Auditory Canal

• Shaped like a cone

• gathers sounds waves from the enviorment and sends them toward the middle ear

Eardrum

• Division between outer and inner ear

• tightly stretched across auditory canal

• When it vibrates it activates ossicles

Ossicles

• Middle ear

• made up of 3 bones

  • Incus, stapes, malleus

  • The stapes vibrates against the oval window

    • this allows sound waves to enter the cochlea

  • Oval window

    • part of cochlea

    • membrane covered opening

    • recieves suond waves from ear drum and vibrate which causes fluid in the cochlea to move

Cochlea

• Contains auditory recpetors called cillia/hair cells

  • embedded in basilar membrane

    • inside fluid filled cochlea

• The inner ear

Cilia/Hair Cells

• Transduces the physcial sound waves into electrical impulses

• auditory nerves send electrical message to brain

• eventually goes through thalamus and arrives in primary auditory cortex, in temporal lobe

Place Theory

• Sound waves vibrate the hair cells

• We identify the pitch of sounds according to the location of vibrations on the basilar membrane

• Auditory receptors for high pitch on left and low pitch on right

• How we sense high pitches

Frequency theory

• Our brain identifies the pitch of sounds according to how repidly the nerve impulses fire

• At high frequencies, neurones fire in teams because no single cell would fire quick enough to match the frequency

Volley Principal

When neurones fire in teams because no single cell would fire quick enough to match the frequency

Conduction Deafness

• Occurs as individual ages

• Ossicles in middle ear age and they become more brittle and may need mroe intense sound waves in order to vibrate

Sensorineural deafness

• Nerve deafness

• caused by famage to hair cells in basilar membrane or auditory nerve

• Sensory receptors for hearing are not performing to fullest capacity

• can be from birth

• can be helped with cochlear implants

Sound Localization

• Ability to determine the origin of a ssound in terms of distance and direction

• Sound waves strike one ear sonner and more intensly than another

Olfaction

Sense of smell

Olfcation cells

• Located along olfactory bulb in nasal cavity

• The receptors are hair cells

• When different sequences of odor receptors fire, we can identify smells

Ansomia

Loss of smell

Pappillae

• Small bump on tongue where taste buds are located

Taste buds

• Receptor cells for taste

• Sensitivity declines with age

• There is sweet, savory, sour, and umami

• They die off which is why our taste evolves

Supertasters

• 25% of people

• very sensitive to potent tastes

• high # of tastebuds

Non-tasters

• Fewer tastebuds

• less sensitive to potent tatses

Synethesia

• Interaction of different senses

Gustory sense

• Tase

• Gustory Cortex

  • in Parietal lobe

Basic tastes

• Sweet

  • indicates energy source

• Salty

  • indicates sodium essental to physiological processes

• Sour

  • indicates potentially toxic acid

• Bitter

  • indicates potential poisions

• Umami

  • indicates proteins to grow and repair tissue

Touch receptors

• Specific receptor cells involved with touch respond to pain, pressure, and temperature

Somatosensory cortex

• In parietal lobe

• Where messages carried by sensory neurons end up

• The more sensitive areas of your body take up more space on the cortex

Homunculus

• Diagram of how much surface area is on somatosenory cortex

Pain

• 2 distinct sets of nerve fibers that carry pain signals from skin to spine

• Heavily myleniatyed and carries pain to brain

Gate control theory of pain

• Theere is a neurological gate in the spinal cord that opens to allow pain messages through to the brain

• It closes to stop messages

• Gate is opened by small fibers to send pain signals

• Gate can be closed by stimulating larger fibers around the injury

Phantom limb pain

• Body part is gone but corresponding part in somasensory cortex is still intact

• If areas on cortex is near where limb used to be and is stimulated, pain can be felt in the “limb”

Kinsethic sense

• Helps to move particular body parts in a precise manner

• Depends on proprioceptors

Propiceptors

• Specialized sensory neurons in joints, tendons, an muscles

• Give us information about position and movement of individual body parts

Vestibular sense

• Sense of balance and whole body positoning

• semicircular canals

• controls vestibular sense

• filled with fluid