sensation? and perception

Sensation

process which stimulated receptors like your eyes and ears create a pattern of neural messages that repersent that stimuli in our brain-gives rise to our initial experience of stimulus

Transduction

The process of converting energy from the environment and changing it to a neural impulse for the brain to read it

Absolute threshold

minimum amount of energy the sense organ can detect

Just-noticeable difference

smallest change in energy that the sense organ can detect-- the amount of change needed to tell that two things are different.

Sensory adaptation

your sensitivity weakens as you become used to the stimulus -- ex: going to a friends house and noticing a unique smell, then not noticing after a few seconds

Weber's law

the change in a stimulus that is just noticeable in a constant ratio of the original stimulus.

Sensory interaction

one sense influences another--ex: smell influences taste

Synesthesia

condition in where the stimulation of one sense generates a simultaneous sensation in another ex: colors being associated with sound

Retina

where sensory receptors for vision are contained (ex: proreceptors + gial) holds rods and cones

Blind spot

a hole in the retina where the optic nerve leaves the eye to enter the brain

Optic nerve

a bundle of nerve fibers that carries visual information from the retina to the brain

Lens

The part of the eye that bends to focus incoming light

Accommodation

process where the eye lens changes shape to focus light on retina

Nearsightedness

refractive error that makes far-away objects look blurry

Farsightedness

refractive error that makes near objects appear blurry

both are an issue with accommodation

Photoreceptors

Light-sensitive cells (neurons) in the retina

-converts light energy into neural energy

Cones have a direct neural pathway to the brain, rods do not

Rods

retinal receptors that detect black white and gray-sensitive to movement (necessary for peripheral vision)

Cones

retinal receptors that are concentrated near the center of the retina- functions in dayllight or well-lot conditions (gives rise to color sensations)

Trichromatic theory

theory of color, that the retina contains three types of color receptors-sensitive to red green blue when stimulated in combo = perception of any color


(blue=short) (green=medium) (red=long)

Opponent-process theory

there are some color combinations that we never see, such as reddish-green or yellowish-blue.

as you look at the yellow, photo receptors of yellow become less responsive

The Trichromatic Color Theory and Opponent Process theory work TOGETHER

Afterimages

occurs when certain ganglion cells in the retina are activated while others are not

- example: ganglion cells involved in this opponent process are red+green, and blue + yellow

Ganglion Cells

projection neurons of the retina
-conveys information from other retinal neurons to the rest of the brain.


**cones have a direct path to the brain

(1 cone : 1 bipolar, :1 ganglion) rods dont..they have a ratio of (5, to 1, to 1)

Dichromatism

people who are blind to red-green or yellow-blue

Monochromatism

totally color blind

Prosopagnosia

face blindness, cannot recognize familiar faces

Blindsight

point where the optic nerve exits the eye
-and where there are no photo receptors...
***any stimulus in this area can be only recognized as black

SOUND

Wavelength

distance between the peak of one light or sound wave to the peak of the next (from short gamma to long radio transmissions)

Pitch

a tones experienced highness or lowness that depends on frequency

Amplitude

Height of a wave or the physical strength of a wave
volume

Loudness

Frequency theory

theory that the perception of pitch depends on the rate at which the entire basilar membrane vibrates

**the whole BM vibrates in respond to sound

Sound localization

we have two ears..so sounds that reach one ear faster than the other ear cause us to localize the sounds place

Conduction deafness

inability to hear, due to damage of the structure of the middle /inner ear

Sensorineural deafness

inability to hear, due to a deficit in the body's ability to transmit impulses from the cochlea to brain

Olfactory system

the sense of smell is olfactory

odor, interacts w/receptor proteins associated with hairs in the nose
the haris convey info to brains olfactorary bulbs

olfaction is assocaited w memory

-SMELL NOT PROCESSED BY THALAMUS!!!

Thalamus

brains sensory control center

Pheromones

Gustation

Sense of taste
-easily damaged by alcohol, smoke, acids or hot food

-gustatory receptors are frequently replaced

6 receptors

unami, sweet, spicy, sour, bitter, MSG, oleogustus

taste is identified on a specialized region of the parietal lobe somatosensory cortex

Taste receptors

Supertasters:person whose sense of taste is greater intensity than the average

Medium tasters: person with an average ability of sense different flavors

Nontasters: person who has less taste perception than most individuals (me sadly)

Sensory interaction

when one sense affects another sense

ex: having congestion makes food not taste the same

Warm/cold receptors

Skin senses- connected to the somatosensory cortex

Humans 4 touch sensations: pain, pressure, cold, and warmth

skin's sensitivity to stimulation varies depending on amount of receptors in each area

Gate control theory

explanation for pain control
- says we have a neural "gate" that under some circumstances, can block incoming pain
-pain is sensed by 2 sensory paths one slow one fast

The level of pain felt is due to a combination of information from both pathways.

Nociceptors

ensory receptors for painful stimuli

Phantom limb

perceived sensation, after removal of a limb, believes that the limb still exists

how pain med work

by blocking the faster neural pathway

Vestibular sense

the sense of body orientation , respecting gravity (balance)

-receptors of info are tiny hairs in the semicircular canal in the inner ear.

Semicircular canals

the three fluid filled bony channels in the inner earwhich provide info about orientation to the brain

-helps to maintain balance (vesticular)

Kinesthesis

gives constant sensory feedback about the muscles and what body is doing

-receptors in joints, muscles and tendons (AUTOMATIC)

Proprioception

perception or awareness of the position and movement of the body

ex: athlete kicking ball without looking @ it

Mastered (3)

You've been getting these terms right!

Pitch perception

The ability to distinguish the tones played at differing frequencies (how high or low given tone is)

Place theory

perception of pitch depends on the area of the basilar membrane that is vibrating

Volley theory

theory that groups of neurons (in the auditory system) respond to a sound by firing APs slightly timed dif with one another so that when combined, a greater frequency of sound can be encoded and sent to the brain = loudness