Psychophysics
* Psychophysics- study of how physical stimuli are translated into psychological experience
Thresholds: Looking for Limits
* Threshold- dividing point between energy levels that do and do not have detectable effect
* Absolute Threshold- minimum amount of stimulation that an organism can detect
* Absolute Threshold- minimum amount of stimulation that an organism can detect
Weighing the Differences: The JND
* Just noticeable Difference (JND)- smallest difference in the amount of stimulation that a specific sense can detect
* Fechner's law- magnitude of a sensory experience is proprotional to the number of JND's that the stimulus causing the experience is above the absolute threshold
* Magnitude estimation- asking subjects to assign numbers to stimuli intensity and sensory experience
- fallible because perceptions can't really be measured on an absolute scale
* Fechner's law- magnitude of a sensory experience is proprotional to the number of JND's that the stimulus causing the experience is above the absolute threshold
* Magnitude estimation- asking subjects to assign numbers to stimuli intensity and sensory experience
- fallible because perceptions can't really be measured on an absolute scale
Signal Detection Theory
* Signal detection theory- detection of stimuli involves decision processes as well as sensory processes, which are both influenced by a variety of factors besides stimulus intensity.
Perception Without Awareness
* Subliminal Perception- registration of sensory input w/o concious awareness
-tied to many controversies
* Make people unconciously want things?
- Usually produces weak effects
-tied to many controversies
* Make people unconciously want things?
- Usually produces weak effects
Sensory Adaptation
* Sensory Adaptation- gradual decline in sensitivity to prolonged stimulation
- you adapt to things and after a while you stop noticing it ( like the smell of your house)
- involuntary
- you adapt to things and after a while you stop noticing it ( like the smell of your house)
- involuntary
Our Sense of Sight: The Visual System
*Humans are visual animals
* If you can see it = Truth
* If you can see it = Truth
The Stimulus: Lights
* Lights vary in amplitude and wavelength
* Humans usually see mixtures of several wavelength
* Purity- how varied light mixed is
* Visual input has to be converted to neural impulses
* Humans usually see mixtures of several wavelength
* Purity- how varied light mixed is
* Visual input has to be converted to neural impulses
The Eye: A Living Optical Instrument
* retina- neural tissue in eye that receives light
* cornea- "window" that light enter the eye through
* Lens- behind cornea, creates the images we see upside-down
-transparent eye structure that focuses light rays falling on retina
* Accomodation- occurs when curvature of lens adjusts to alter visual focus
- when you focus on a close object lens of eyes gets fatter (rounder) to give a clear image with distant objects, lens flattens out
* nearsightedness- close objects are seen clearly but distant objects are blurry
- happens when distant objects fall short of retina of when eyeball is too long
* Farsightedness (me!)- distant objects are clear but close objects are blurry
- happens when light falls behind retina or when eyeball is too short
* Pupil- opening in the center of iris that helps regulate the amount of light passing into near chamber of the eye
- when constricted- less light in eye and sharpens image
- dilated- more light and less sharp image
* cornea- "window" that light enter the eye through
* Lens- behind cornea, creates the images we see upside-down
-transparent eye structure that focuses light rays falling on retina
* Accomodation- occurs when curvature of lens adjusts to alter visual focus
- when you focus on a close object lens of eyes gets fatter (rounder) to give a clear image with distant objects, lens flattens out
* nearsightedness- close objects are seen clearly but distant objects are blurry
- happens when distant objects fall short of retina of when eyeball is too long
* Farsightedness (me!)- distant objects are clear but close objects are blurry
- happens when light falls behind retina or when eyeball is too short
* Pupil- opening in the center of iris that helps regulate the amount of light passing into near chamber of the eye
- when constricted- less light in eye and sharpens image
- dilated- more light and less sharp image
The Retina: Brain's Envoy in the Eye
* Retina- neural tissue lining inside back surface of the eye, absorbs light, processes images, sends visual info to brain
- axons run from retina to brain then go optic disk
- Optic disk- hole in retina where optic nerve fibers exit the eye
- can't see part of the image that falls on the optic disk, so it's a blind spot
Visual Receptors: Rods and Cones
* retina has millions of receptor cells thats are sensitive to light
- in innermost layer of retina therefore only 10% of light arriving in cornea reach receptors
* 2 types of receptors:
1. Rods
- specialized visual receptors that play a role in night vision and peripheral
- outnumbers cones, have 100-125 million
2. Cones
- specialized visual receptors that play a key role in daylight vision and color vision
- handle most daytime vision
- provide better acuity
- visual acuity- sharpness and precise detail
- concentrated in center of retina
- 5-6.4 million cones
* Fovea- tiny spot on the center of retina contains only cones, visual acuity is greatest here
Dark and Light Adaptation
* Dark adaptation- eyes more sensitive to light in low illumination
- complete in around 30 minutes
* Light adaptation- eyes less sensitive to light in high illumination
- opposite of dark adaptation
Information Processing in the Retina
* light striking the retina's receptors triggers neural signals that pass into the intricate network of cells in the retina then sends impulses to optic nerve
* optic nerve- collection fo axons that connect eye w/ brain
- go through optic disk, then carry visual info to brain
* 100 million rods and cones converge and travel through 1 million axons
* Receptive Feild- retinal area that, when stimulated, affects firing of that cell
- light in center feild- increased rate of firing
- light in surrounding feild- decreased rate of fire
- light in both feilds- baseline firing
*Lateral antagonism- occurs when neural activity in a cell opposes activity in surrounding cells (this is complex, look at pictures in book and read)
- axons run from retina to brain then go optic disk
- Optic disk- hole in retina where optic nerve fibers exit the eye
- can't see part of the image that falls on the optic disk, so it's a blind spot
Visual Receptors: Rods and Cones
* retina has millions of receptor cells thats are sensitive to light
- in innermost layer of retina therefore only 10% of light arriving in cornea reach receptors
* 2 types of receptors:
1. Rods
- specialized visual receptors that play a role in night vision and peripheral
- outnumbers cones, have 100-125 million
2. Cones
- specialized visual receptors that play a key role in daylight vision and color vision
- handle most daytime vision
- provide better acuity
- visual acuity- sharpness and precise detail
- concentrated in center of retina
- 5-6.4 million cones
* Fovea- tiny spot on the center of retina contains only cones, visual acuity is greatest here
Dark and Light Adaptation
* Dark adaptation- eyes more sensitive to light in low illumination
- complete in around 30 minutes
* Light adaptation- eyes less sensitive to light in high illumination
- opposite of dark adaptation
Information Processing in the Retina
* light striking the retina's receptors triggers neural signals that pass into the intricate network of cells in the retina then sends impulses to optic nerve
* optic nerve- collection fo axons that connect eye w/ brain
- go through optic disk, then carry visual info to brain
* 100 million rods and cones converge and travel through 1 million axons
* Receptive Feild- retinal area that, when stimulated, affects firing of that cell
- light in center feild- increased rate of firing
- light in surrounding feild- decreased rate of fire
- light in both feilds- baseline firing
*Lateral antagonism- occurs when neural activity in a cell opposes activity in surrounding cells (this is complex, look at pictures in book and read)
Vision and Brain
- TIME TO TALK ABOUT VISUAL PROCESSING! yay
Visual Pathways to the Brain
* optic chiasm- point at with optic nerves from indide half of each eye cross over and then project to opposite half of brain
- ensures that signals from both eyes go to both hemispheres
* axons from left half of retina will carry signals to the laft side of brain and vice versa
* after reaching optic chiasm, optic fibers diverge along 2 pathways
- main path projects into thalamus
-90% of axons synapse in LGN then get distributed to primary visual cortex
- second pathway branched off to area of midbrain called superior colliculus
* main pathways is subdivided ino more specialized pathways called nagnocellular and parvocellular
- channels in parallel processing- simultaneousely extracting different kinds of info from same input
* parvocellular channel gets color
magnocellular channel gets brightness
- ensures that signals from both eyes go to both hemispheres
* axons from left half of retina will carry signals to the laft side of brain and vice versa
* after reaching optic chiasm, optic fibers diverge along 2 pathways
- main path projects into thalamus
-90% of axons synapse in LGN then get distributed to primary visual cortex
- second pathway branched off to area of midbrain called superior colliculus
* main pathways is subdivided ino more specialized pathways called nagnocellular and parvocellular
- channels in parallel processing- simultaneousely extracting different kinds of info from same input
* parvocellular channel gets color
magnocellular channel gets brightness
Information Processing in Visual Cortex
* individual cells in primary cortex don;t respond much to little spots but are more sensitive to complex shit like lines and edges. (they like living on the edge.)
* simple cell-respond best to a line w/ correct width oriented at a correct angle, and in correct location in it's receptive feild.
* Complex cells- care about width and orientation but they respond to any position in receptive feild (sounds like simple cells are more complex)
* Feature Detectors- neurons that respond selectively to very specific features of more complex stimuli
* after visual input is processed in primary visual cortex it's often routed to other cortical areas for processing
-aka what and where pathways
* ventral stream- processes "what" objects are (form and color)
* Dorsal stream- processes "where" objects are (motion and depth)
*Visual Agnosia- inability to recognize objects even if they have good vision
* simple cell-respond best to a line w/ correct width oriented at a correct angle, and in correct location in it's receptive feild.
* Complex cells- care about width and orientation but they respond to any position in receptive feild (sounds like simple cells are more complex)
* Feature Detectors- neurons that respond selectively to very specific features of more complex stimuli
* after visual input is processed in primary visual cortex it's often routed to other cortical areas for processing
-aka what and where pathways
* ventral stream- processes "what" objects are (form and color)
* Dorsal stream- processes "where" objects are (motion and depth)
*Visual Agnosia- inability to recognize objects even if they have good vision
Veiwing World in Color
- now we'll talk about color (yay)
The Stimulus for Color
* longer wavelengths of light look red shorter wavelengths look violet
- color= psychological interpretation
* wavelength affects hue, amplitude effects brightness, purity effects saturation
* Humans can discriminate among a million colors
* Subtractive color mixing- removing wavelengths of light leaving less light than originally there
- paints have subtractive mixing b/c the pigments absorb wavelengths
* Additive color mixing- superimposing lights, putting more light in mixture than exists in anyone light itself
- color= psychological interpretation
* wavelength affects hue, amplitude effects brightness, purity effects saturation
* Humans can discriminate among a million colors
* Subtractive color mixing- removing wavelengths of light leaving less light than originally there
- paints have subtractive mixing b/c the pigments absorb wavelengths
* Additive color mixing- superimposing lights, putting more light in mixture than exists in anyone light itself
Trichromatic Theory of Color Vision
* Trichromatic theory- human eye has 3 types of recpetors w/ differing sensitivities to different light wavelengths
* colorblindness- encompasses a variety of deficiencies in ability to distinguish colors
- common more in males
- color blinds are dichromats- only have 2 channels of color
* colorblindness- encompasses a variety of deficiencies in ability to distinguish colors
- common more in males
- color blinds are dichromats- only have 2 channels of color
Opponent Process theory of color vision
* complementary colors- colors that mix together to make gray tones
* after image- a visual image that persists after stimulus is removed
* opponent process theory- color perception depends on receptors that make antagonistic responses to 3 pairs of colors
* after image- a visual image that persists after stimulus is removed
* opponent process theory- color perception depends on receptors that make antagonistic responses to 3 pairs of colors
Reconciling Theories of Color Vision
* takes both theories ot explain color vision
* eye has 3 different types of cones, each being sensitive to a different band of wavelengths
* cells in retina, LGN, and visual cortex respond in opposite ways, red vs. green & blue vs. yellow
* eye has 3 different types of cones, each being sensitive to a different band of wavelengths
* cells in retina, LGN, and visual cortex respond in opposite ways, red vs. green & blue vs. yellow
Perceiving Forms, Patterns, and Objects
* reversible figure- drawing thats compatible w/ 2 interpretations
* perceptual set- a readiness to perceive stimulus in a particular way
* inattentional blindness- failure to see fully visible objects or events in a visual display
* perceptual set- a readiness to perceive stimulus in a particular way
* inattentional blindness- failure to see fully visible objects or events in a visual display
Feature Analysis: Assembling Forms
*Feature analysis: process of detecting specific elements in visual input and assembling them into a more complex form
* subjective contours- perception of contours where none actually exist
* subjective contours- perception of contours where none actually exist
Looking at the Whole Picture: Gestalt Principles
* Phi Phenonmenon- illusion of movement created by presenting visual stimuli in rapid succession (like a flip book!)
* Law of pergnanz- people group elements that combine to form a good figure
* Law of pergnanz- people group elements that combine to form a good figure
Formulating Perceptual Hypotheses
* 2 types of stimuli
1. Distal Stimuli- stimuli that lie in the distance ( world outside body)
- objects you're looking at
2. Proximal Stimuli- stimulus energies that impinge directly on sensory recptors
- 2 dimensional versions of actual 3D counter parts
* perceptual hypothesis- inference about which distal stimuli could be responsible for proximal stimuli sensed
* you expect to see things so if I typed tihs you expected to see this (that's why you understand all the typos i make)
1. Distal Stimuli- stimuli that lie in the distance ( world outside body)
- objects you're looking at
2. Proximal Stimuli- stimulus energies that impinge directly on sensory recptors
- 2 dimensional versions of actual 3D counter parts
* perceptual hypothesis- inference about which distal stimuli could be responsible for proximal stimuli sensed
* you expect to see things so if I typed tihs you expected to see this (that's why you understand all the typos i make)
Perceiving Depth or Distance
* depth perception- interpretation of visual cues that indicate how near or far away objects are
* people rely on a variety of clues classified into 2 types
1. binocular cues
- clues about distance based on differing veiws of the 2 eyes
- retinal disparity- object within 25 ft. project images slightly different locations onf right and left retinas, so the right and left eyes see slightly different veiws of an object
- the closer an object gets the greater the disparity between images seen by each eye
2. monocular depth
- clues about distance based on either eye alone
- 2 kinds
1. result of active eye in veiwing world( if you cover 1 eye, closer objects seem to move more than distant ones)
- motion parallax- involved images of objects at different distances moving across retina at different rates
2. pictoral depth cues
- clues about distancwe that can be given in a flat picture
* people rely on a variety of clues classified into 2 types
1. binocular cues
- clues about distance based on differing veiws of the 2 eyes
- retinal disparity- object within 25 ft. project images slightly different locations onf right and left retinas, so the right and left eyes see slightly different veiws of an object
- the closer an object gets the greater the disparity between images seen by each eye
2. monocular depth
- clues about distance based on either eye alone
- 2 kinds
1. result of active eye in veiwing world( if you cover 1 eye, closer objects seem to move more than distant ones)
- motion parallax- involved images of objects at different distances moving across retina at different rates
2. pictoral depth cues
- clues about distancwe that can be given in a flat picture
Perceiving Geographical Slant
* making judgement about how steep hills are and other inclines
- neglected by researcher.. until now!
HEY YOU LAZY ASS READ THIS SECTION.
* hills looks steeper when a person is tired
- neglected by researcher.. until now!
HEY YOU LAZY ASS READ THIS SECTION.
* hills looks steeper when a person is tired
Perceptual Constancies in Vision
* Perceptual Constancy- tendency to experience a stable perception in the face of continually changing sensory input
Power of Misleading Cues: Optical Illusions
* Optical Illusion- apparently inexpicable discrepancy between the appearance of a visual stimulus and it's physical reality
* Impossible Figures- object that can be represented in 2D pictures but not in 3D space
-LOOK AT ILLUSIONS IN YOUR BOOK YOU SLACKER!
* People in underdeveloped countries don't see a differnce in these pictures b/c they aren't experienced with them.
* Impossible Figures- object that can be represented in 2D pictures but not in 3D space
-LOOK AT ILLUSIONS IN YOUR BOOK YOU SLACKER!
* People in underdeveloped countries don't see a differnce in these pictures b/c they aren't experienced with them.
Our Sense of Hearing: The Auditory System
* now's the time to learn about hearing
The Stimulus: Sound
* sound waves move at a fraction of the speed of light (damn, that's fast)
* Characterized by amplitude, wavelength, and purity
* Characterized by amplitude, wavelength, and purity
Human Hearing Capacities
* Frequency is measured in hertz (cycles per second
- higher frequencies have higher pitch
* humans can hear from 20Hz to 20,000 Hz
* amplitude measured in decibles (dB)
* perceived loudness doubles every 10 decibels
* purity of sound- single frequency of vibration
- higher frequencies have higher pitch
* humans can hear from 20Hz to 20,000 Hz
* amplitude measured in decibles (dB)
* perceived loudness doubles every 10 decibels
* purity of sound- single frequency of vibration
Sensory Processing in the Ear
* EAR DIVIDED INTO 3 SECTIONS(i'm too lazy to retype that in regular letters)
1, external ear
- depends on vibration of air molecules
- consists mainly of pinna (The cartilage that you get peirced)
- soundwaves collected by pinna goes to eardrum- taut membrane that vibrates in response
2. Middle Ear
- depends on vibrations of moveable bones
- tiniest bones in body called the hammer, and the anvil, and the stirrup (all called the oscicles)
- it converts large movement with tiny force to tiny movements with large force
3. inner ear
- depends on waves in a fluid
- cochlea- fluid filled snail looking thing w/ receptors for hearing
- ear's neural tissue is in the cochlea and is like a retina
- basilar membrane- runs length of spiraled cochlea, holds auditory recpetors
- auditory receptors are called hair cells b/c they have bundles of hair (hairyyyyy, harry, voldemort.)
- work like rods and cones of the eye
* signals go through thalamus --> auditory cortex
1, external ear
- depends on vibration of air molecules
- consists mainly of pinna (The cartilage that you get peirced)
- soundwaves collected by pinna goes to eardrum- taut membrane that vibrates in response
2. Middle Ear
- depends on vibrations of moveable bones
- tiniest bones in body called the hammer, and the anvil, and the stirrup (all called the oscicles)
- it converts large movement with tiny force to tiny movements with large force
3. inner ear
- depends on waves in a fluid
- cochlea- fluid filled snail looking thing w/ receptors for hearing
- ear's neural tissue is in the cochlea and is like a retina
- basilar membrane- runs length of spiraled cochlea, holds auditory recpetors
- auditory receptors are called hair cells b/c they have bundles of hair (hairyyyyy, harry, voldemort.)
- work like rods and cones of the eye
* signals go through thalamus --> auditory cortex
Auditory Perception: Theories of Hearing
* 2 theories have dominated the WORLD OF HEARING
1. place theory
-holds that perception of pitch corresponds to vibration of different portions, or places along the basilar membrane
- hair cells at various locations respond independently
- like feature analysis but for your ears
2. Frequency Theory
- holds that perception of pitch corresponds to the rate/frequency at which the entire basilar membrane vibrates
- whole membrane responds in unison to sounds
- so sound frequency at 3000 Hz should theoretically cause the basilar membrane to vibrate at a corresponding rate of 3000 times per secind
Reconciling Place and Frequency Theories
* both theories had flaws but both had something right in them.
* place theory is wrong b/c hair on membrane isn't independent
- vibrate together
- correct b/c wave peaks at certain places
* frequency theory is wrong b/c neurons don't need that many signals (the 3000 thingy i talked about before)
* volley principle- groups of auditory nerve fibers fire neural impulses in rapid succession, creating volleys of impulses.
- we can generate volleys of 5000 impulses per second
1. place theory
-holds that perception of pitch corresponds to vibration of different portions, or places along the basilar membrane
- hair cells at various locations respond independently
- like feature analysis but for your ears
2. Frequency Theory
- holds that perception of pitch corresponds to the rate/frequency at which the entire basilar membrane vibrates
- whole membrane responds in unison to sounds
- so sound frequency at 3000 Hz should theoretically cause the basilar membrane to vibrate at a corresponding rate of 3000 times per secind
Reconciling Place and Frequency Theories
* both theories had flaws but both had something right in them.
* place theory is wrong b/c hair on membrane isn't independent
- vibrate together
- correct b/c wave peaks at certain places
* frequency theory is wrong b/c neurons don't need that many signals (the 3000 thingy i talked about before)
* volley principle- groups of auditory nerve fibers fire neural impulses in rapid succession, creating volleys of impulses.
- we can generate volleys of 5000 impulses per second
Auditory Localization: Perceiving Sources of Sounds
* auditory localization- locating source of sound in space
- it's analagous to recognizing depth in vision
* 2 cues are improtant to sound
1. intensity (loudness)
- sound source gets louder as things are closer
2. Timing of sounds
- sounds furthur away will be heard later than sounds closer to you.
- it's analagous to recognizing depth in vision
* 2 cues are improtant to sound
1. intensity (loudness)
- sound source gets louder as things are closer
2. Timing of sounds
- sounds furthur away will be heard later than sounds closer to you.
Our Chemical Senses: Taste and Smell
* gustatory system- sensory system for taste (me gusta!)
* Olfactory system- sensory system for smell (does it smell like an old factory?)
* Olfactory system- sensory system for smell (does it smell like an old factory?)
Taste: The Gustatory System
* Stimuli of taste involves chemicals that are soluble
* Taste buds- gustatory receptors that are clusters of taste cells that line trenches around tiny bumps in the tongue
- trigger neural impulses--> thalamus--> cortex
- taste cells only last 10 days and are constantly being replaced
* 4 primary tastes
1. sweet
2. bitter
3. sour
4. salty
* basic tastes preferences appear to be innate and automatically regulated by physiological mechanisms sometimes
- i.e: infants like sweet tastes and react negatively to bitter, salty, or sour tastes.
* taste preferences are usually learned and heavily influenced by social processes
- depends on what you are exposed to
* people vary in sensiivity to certain tastes
* supertasters- people that have four times as more taste buds per square centimeter than people on the other side of the spectrum- nontasters
- more women are supertasters
* odor contributes to taste
* identifying taste declines with absense of odors
* Taste buds- gustatory receptors that are clusters of taste cells that line trenches around tiny bumps in the tongue
- trigger neural impulses--> thalamus--> cortex
- taste cells only last 10 days and are constantly being replaced
* 4 primary tastes
1. sweet
2. bitter
3. sour
4. salty
* basic tastes preferences appear to be innate and automatically regulated by physiological mechanisms sometimes
- i.e: infants like sweet tastes and react negatively to bitter, salty, or sour tastes.
* taste preferences are usually learned and heavily influenced by social processes
- depends on what you are exposed to
* people vary in sensiivity to certain tastes
* supertasters- people that have four times as more taste buds per square centimeter than people on the other side of the spectrum- nontasters
- more women are supertasters
* odor contributes to taste
* identifying taste declines with absense of odors
Smell: Olfactory System (I was about to write old factory system)
* chems are dissolved in nose mucus (aka your booger or if you're english- bogies)
* olfactory cilia- hairlike structures at uppper portion of nasal passages that receive smell
- last 30-60 days--> constantly being replaced
* axons synapse w/ cells in olfactroy bulb--> directly go to various areas in cortex
- doesn't go to thalamus
*shows sensory adaptation- like taste (ya know aquired tastes.)
* humans can distinguish between 10,000 different odors
- people have difficulty attaching names to them though
- females are more accurate
* olfactory cilia- hairlike structures at uppper portion of nasal passages that receive smell
- last 30-60 days--> constantly being replaced
* axons synapse w/ cells in olfactroy bulb--> directly go to various areas in cortex
- doesn't go to thalamus
*shows sensory adaptation- like taste (ya know aquired tastes.)
* humans can distinguish between 10,000 different odors
- people have difficulty attaching names to them though
- females are more accurate
Our sense of touch: Sensory Systems in the Skin
* Stimuli for touche include: mechanical, thermal, and chemical energy
Feeling Pressure (under pressure-queen, listen to it now)
* cells in nervous system that respond to touch are sensitive to specific patches on the skin
- skin patches vary in size and are the functional equivilent of receptive feilds in vision
* involves center-surround arrangement
- stimuli falling in center produce opposite effect of stimuli in surrounding area
* spinal cord-> brainstem-> opposite side of brain-> thalamus-> somatosensory cortex
- somatosensory cortex acts like feature detetectors in vision-> respond to specific features like direction of a stroke (ooh la la)
- skin patches vary in size and are the functional equivilent of receptive feilds in vision
* involves center-surround arrangement
- stimuli falling in center produce opposite effect of stimuli in surrounding area
* spinal cord-> brainstem-> opposite side of brain-> thalamus-> somatosensory cortex
- somatosensory cortex acts like feature detetectors in vision-> respond to specific features like direction of a stroke (ooh la la)
Feeling PAIN
* Pain= warning system of our body
* it tells people when to stop( now we just got to get some people to stop talking)
Pathways to the Brain
* Pain messages are transmitted to brain throught 2 pathways:
1. fast pathway
- registers localized pain and relays it to cortex in a fraction of a second
- sharp pain when you first get hurt
- depend on A-delta fibers- thick myelinated neurons
2. Slow pathway
- lags a sec or 2 behind fast system
- less localized, longer lasting, aching/ burning from initial injury
- depend on C-Fibers- thin, unmyelinated neurons
Puzzles in Pain Perception
* pain not auromatic to pain stimulation- can be affected by mental stuff, like mood, personality, etc.
* when you get distracted hurting temporaily goes away.
* Gate- control Theory- incoming pain sensations must pass through and imaginary gate in spinal cord that can be closed, thus blocking pain signals
- little support for this theory though
- endorphins get into play for this
* -insert something you should read in book b/c i didn't understand this-
* it tells people when to stop( now we just got to get some people to stop talking)
Pathways to the Brain
* Pain messages are transmitted to brain throught 2 pathways:
1. fast pathway
- registers localized pain and relays it to cortex in a fraction of a second
- sharp pain when you first get hurt
- depend on A-delta fibers- thick myelinated neurons
2. Slow pathway
- lags a sec or 2 behind fast system
- less localized, longer lasting, aching/ burning from initial injury
- depend on C-Fibers- thin, unmyelinated neurons
Puzzles in Pain Perception
* pain not auromatic to pain stimulation- can be affected by mental stuff, like mood, personality, etc.
* when you get distracted hurting temporaily goes away.
* Gate- control Theory- incoming pain sensations must pass through and imaginary gate in spinal cord that can be closed, thus blocking pain signals
- little support for this theory though
- endorphins get into play for this
* -insert something you should read in book b/c i didn't understand this-
Our other Senses
* we have 2 more senses -GASP-
Kinesthetic System
* kinesthetic system- monitors positions of various parts of the body
- self explanatory
- self explanatory
Vestibular System
* vestibular system- responds to gravity and keep you informed of your position in space
- provides sense of balance
* semi circular canals- inside inner ear, make up a large part of vestibular system
- fluid flows through them, shift in fluid are detected by hair cells
- provides sense of balance
* semi circular canals- inside inner ear, make up a large part of vestibular system
- fluid flows through them, shift in fluid are detected by hair cells