touch

staircase method

A stimulus (e.g., odorant) is presented in an ascending concentration sequence until detection is indicated, and then the concentration is shifted to a descending sequence until the response changes to "no detection." Also called reverse staircase method.

tactile

mechanical interactions with the skin (adjective form of touch, e. grabbing)

kinesthesia

perception of the body's own movements

Proprioception

sensory input from internal organs

Somatosensation

Collective sensory signals from the body

Mechanoreceptors

tactile receptors that respond to mechanical stimulation (pressure, vibration, or movement)

a-beta fiber

myelinated class of tactile nerve fibers with wide diameters that allow very fast signal transmission.

glabrous

lack of hair

Four names of mechanoreceptor endings

meissner corpusde (FA1), merkel cell neurite complexes (SA1), pacinian corpuscles (FA1), ruffini ending (SA1)

Thermoreceptors and the two types

respond to changes in skin temperature. Two types are warmth and cold fibers

warmth fibers and cold fibers

warrmth- fires when skin temperature increases

cold- fires when skin temperature decreases

C fibers

transmits pain and temperature signals through unmyelin nerve

A-delta fibers

transmits pain and temperature signals through myelinated nerve

Nociceptors

responds to painful input like extreme heat or pressure

C tactile (CT) afferent

unmyelinated sensory nerve fiber that transmits signals from pleasant touch.

labeled lines

each fiber type codes a particular touch sensation

dorsal horn

rear of the spinal cord that receives inputs from receptors in the skin

somatotypical

having normal somatosensation

spinothalamic pathway

major pathway from touch receptor to brain. slow, carries most info about skin temperature and pain to the brain

dorsal column-medial lemniscal pathway

major pathway from touch receptors to brain. fast, carries info from mechanoreceptors

somatosensory area 1

primary receiving area for touch in cortex

somatosensory area 2

the secondary receiving area for touch in the cortex

homunculus

a maplike diagram of regions of the body in the brain

body image

the impression of our bodies in space

neural plasticity

the ability of the brain to change in response to experience

substantia gelatinosa

the dorsal region of the spinal cord where both fast and slow pain fibers synapse with sensory nerves on their way to the brain

anterior cingulate cortex

perceived unpleasantness of pain sensation

analgesia

decreasing pain sensations without losing consciousness (drugs, anticipation, prior experience, excitement)

endogenous opiates

a chemical released by the body that blocks the release or uptake of neurotransmitters necessary to transmit pain sensations to the brain (didn't feel pain from hitting the hurdle until after I crossed the finish line)

placebo effect

people think they're taking a drug that reduces pain but it really doesn't

Hyperalgesia

heightened response to normally painful stimulus

two-point touch threshold

smallest separation that we can tell we are being touched by two points and not just one

haptic perception

the active exploration of the environment by touching and grasping objects with our hands

exploratory procedures

way of feeling an object in order to learn about its properties

(lateral motion for texture, pressure for hardness, static contact for temperature, unsupported holding for weight, enclosure for volume, etc)

tactile agnosia

inability to identify objects by touch

frame of reference

the coordinate system used to define locations in space

egocenter

the center of a reference frame used to represent locations relative to the body (for vision, it's bridge of the nose)

Endogenous

if people anticipate being touched, attention goes top down, anticipates where stimulus will occur

exogenous

if people anticipate being touched, attention goes bottom up, attention goes where stimulus appeared

Where is the sense of touch found?

skin

where are the meissner and merkel receptors

between epidermis and dermis

where are the pacinian and ruffini receptors located

deeply in dermis and underlying subcutaneous tissue

how are the four mechanoreceptors classified

size of receptive field and rate of adaptation

SA I

texture and pattern perception (reading Braille, slot of screw when we can feel but can't see)

SA II

lateral skin stretch when we grasp an object, finger position

FA I

senses when object is going to fall through your fingers, helps with stable grasp

FA II

fine texture perception, when object first makes contact with skin (mosquito landing on arm)

Feeling shape of key requires _________, shaping your fingers to grasp key requires ________, inserting key into lock and gripping key so it doesn't fall requires _______, knowing when key hits end of keyhole requires ________.

SA I, SA II, FA I, FA II

emmetropia

normal vision

hyperopia

A condition in which visual images come to a focus behind the retina of the eye and vision is better for distant than for near objects -- called also farsightedness.

myopia

nearsightedness

presbyopia

impaired vision as a result of aging

macular degeneration

loss of central vision, due to aging, results in retina

What functionality would be affected if you lost your SA 1 touch receptors?

texture perception and pattern/form perception

mechanoreceptors that have a fast adaptation rate and large receptive field size are called...

pacinian corpuscles

When you stub your toe, you first feel a quick sharp pain transmitted by ______, and then a moment later, a dull throbbing pain transmitted by _________.

A-delta fibers, C fibers

If you stick your hand in a bucket of ice water for a few moments you will most likely feel both cold and pain sensations. Which pathway, from the spinal cord to the brain, carries this information?

spinothalamic

The spinothalamic pathway decussates (crosses to the other side) at the ______ while the dorsal column-medial lemniscal pathway decussates at the __________.

level of entry, medulla

Suppose you are a patient in one of Penfield's famous experiments involving stimulation of the somatosensory cortex. During the procedure, the brain stimulation causes you to feel a tingling in your right arm. If Penfield moves the probe a centimeter along the cortex and stimulates the brain there, which part of your body will most likely feel a tingle.

right elbow

suppose you hit your shin on a piece of furniture and it starts to hurt. Which theory explains why rubbing your shin might make it hurt less?

gate control theory

Which concept explains why a cut on your finger is more sensitive to pain until it heals?

hyperalgesia

suppose you reach into the depths of your backpack without looking and find a pencil using your sense of touch alone. You have just engaged in __________ perception.

haptic

suppose a rat pup is born to a mother who does not lick and groom her offspring but is raised by a foster mother who does lick and groom the rat pup. What can we expect of the rat pup's behavior as they mature?

The rat pup will be less timid and more likely to groom its own offspring

______ is the sensation evoked by solutions that contact receptors in the tongue, while _______ includes the former and also retronasal olfaction.

taste, flavor

Anesthesia of the chorda tympani causes

damaged taste

foliate papillae

taste bud-containing folds of tissue that are located on the rear of the tongue, where the tongue attaches to the mouth

when you compare the tongue of a supertaster to the tongue of a nontaster, what difference do you notice?

The supertaster has a much higher density of fungiform papillae than the nontaster

what taste quality is produced by the hydrogen ion in foods

sour

which specific taste may have evolved to help us sense poisonous foods?

bitter

The ability to match the intensities of sensations that come from different sensory modalities is known as

cross-modality matching

what taste receptors do fat molecules stimulate?

none

The gustatory system is responsible for...

detecting nutrients and "antinutrients" before we ingest them

The labeled lines theory of taste coding holds that each ________ carries a particular taste quality

taste nerve fiber

_____________ olfaction refers to sniffing in and perceiving odors through the nostrils, while _______ olfaction refers to perceiving odors through the mouth while chewing.

orthonasal, retronasal (flavor)

All food tastes pretty bland to him -- he can only sense the sweetness, saltiness, bitterness, or sourness of food, but none of the other complexities. What is the best diagnosis for John?

anosmia

What is the second layer of cells surrounding the glomeruli?

tufted cells

what forms part of the deepest layer of cells in the olfactory bulb?

granule cells

Sometimes odorants can stimulate the somatosensory system through polymodal nociceptors. These sensations are mediated by the _________, which transmits information about the "feel" of an odorant.

Trigeminal nerve

This odor is created when at least 30 odorants of equal intensity that span olfactory physiochemical and psychological (perceptual) space are mixed. The resultant odor percept is the same as every other mixture of 30 odorants meeting the span and equivalent intensity criteria, even though the various mixtures do not share any common odorants.

olfactory white

Suppose a person's olfactory system is "rewired" such that olfactory signals pass through the thalamus and are processed more in the left hemisphere of the brain. What might be a consequence?

It would be easier for them to verbally label smells

Suppose you leave town for a few weeks and when you return, your house has a strange smell that you didn't notice before you left. What might be the explanation?

Cognitive habituation

If your friend is wearing a new perfume and you decide you really like it, you have just made a _________judgment.

hedonic

The __________ is the part of the brain responsible for processing olfaction and for assigning affective value to stimuli.

orbitofrontal cortex

what can affect your tactile sensitivity?

age, genes

action for perception

Using our hands to actively explore the world of surfaces and objects outside our bodies

perception for action

sensory input is used to prepare us to interact with objects and surfaces around us

how many classes of pressure sensitive mechano receptors are there within hairy skin?

5

how many classes of pressure sensitive mechano receptors are there within hairless skin?

4

Olfaction

sense of smell

Gustation

sense of taste

Olfactory apparatus

a group of organs used for smell

olfactory sensory neurons

the sensory receptors for smell that reside high up inside the nose, they are bipolar neurons and have one axon and one dendrite

pseudogenes

unused genes of olfactory sensory neurons

do people with less olfactory sensory neurons like or dislike the smell of a skunk?

They tend to like it

shape-pattern theory

shapes of molecules bring a specific sense (odorant fits into odorant receptors like a puzzle

vibration theory

How fast molecules vibrate, proposes that every odorant has a different vibrational frequency, and that molecules that produce the same vibrational frequencies will smell the same.

Do we believe the vibration theory?

no

If D carvone and L carvone cells are the same shape, what makes them smell different?

position of one atom

how smell travels

OSN- Glomeruli- tufted/mitral cells- brain- piriform cortexh

Cranial Nerve Acronym

Once On Olympus' Towering Top A Finely Vested German Viewed A Hawk (olfactory, optic, oculomotor, trochlear, trigenial, abducens, facial, vestibula cochlear, glossophanygeal,, vagur, (spinal) accessory, hypoglossal