Chapter 4 Sensation

Front 1

Transduction

Back 1

process of converting incoming energy into neural activity

takes place at sensory receptors, specialized cells that detect certain forms of energy

Front 2

Adaptation

Back 2

a process through which responsiveness to an unchanging stimulus decreases over time

*why touch sensations from glasses disappear shortly after you put them on

Front 3

Coding

Back 3

Translation of physical properties of a stimulus into a pattern of neural activity that specifically identifies those properties

Front 4

Doctrine of specific nerve energies

Back 4

Stimulation of a particular sensory nerve provides code for that one sense, no matter how the stimulation takes place (apply pressure to eyeball, optic nerve has activity)

Front 5

Temporal code

Back 5

coding attributes of a stimulus in terms of changing in the timing of neural firing

Front 6

Spatial code

Back 6

coding attributes of a stimulus in terms of the location of firing neurons relative to their neighbors

Front 7

Amplitude is....
Determines...

Back 7

difference in air pressure from baseline to peak of the wave

determines LOUDNESS
(Decibels)

Front 8

Wavelength is...

Back 8

distance from one wave peak to the next

Front 9

Frequency is...
Determines...

Back 9

# of complete waveforms/cycles that pass by a given point each second (hertz)

determines pitch

Front 10

Timbre

Back 10

A sound's quality

Complex waveforms added to the fundamental frequency that makes up a sound wave produce timbre

Front 11

Describe the movement of sound through the auditory accessory structures

Back 11

Pinna collects sound waves

Strike the tympanic membrane

Produces a vibration that causes the malleus (hammer), incus (anvil), and stapes (stirrup) to vibrate

Front 12

Describe the Auditory transduction process

Back 12

Vibrations pass through the oval window & fluid in the cochlea

Move the basilar membrane, which stretches along the floor of the cochlea

Movement of the basilar membrane causes tiny hair cells that touch it to move

Hair-cell movement causes neuron activity in the auditory nerve, which carries auditory information on the brain

This process is known as auditory transduction

Front 13

3 tiny inner ear bones

Back 13

Malleus-hammer
Incus-anvil
Stapes-stirrup

Front 14

Conduction deafness

Back 14

Caused by problems w/ bones in the inner ear

Front 15

Nerve deafness

Back 15

Problems w/ the auditory nerve or hair cells

Front 16

What is used to localize sounds?

Back 16

Temporal code

Front 17

What does place theory say about how frequency is coded?

Back 17

hair cells at a particular place on the basilar membrane respond most to the wave peak associated with a particular frequency of sound

High frequencies are coded exclusively by the place where the wave peaks

Front 18

What does frequency matching theory say about how frequency is coded?

Back 18

The firing rate of a neuron in teh auditory nerve matches the frequency of a sound wave

Lowest frequencies coded by frequency matching

Low to moderate frequencies are coded by frequency matching & by the place on the basilar membrane where the traveling wave peaks

Volley theory = another name for it

Front 19

Visible light is __________ radiation that has a wavelength from about ____ to ____ nanometers.

Back 19

electromagnetic
450
700

Front 20

Our sensation depends on ______ ____ and _____ ________.

Back 20

Light intensity
light wavelength

Front 21

Light waves pass through the ____, the _____, and the ____ before being focused on the ______.

Back 21

Cornea
Pupil
Lens
Retina

Front 22

Iris

Back 22

Adjusts the size of the pupil opening

Front 23

Accommodation

Back 23

The cornea & the muscles that hold the lens in place focus the light on the retina through this process

Front 24

Dark adaptation

Back 24

gradually increasing ability to see in the dark

occurs as new photopigments are synthesized

Front 25

Photopigments

Back 25

Found in photoreceptors: break down in reaction to light & cause changes in photoreceptor membrane potential

Front 26

What is the difference between rods & cones?

Back 26

Rods: more sensitive to light
*Contain the photopigment rhodopsin

Cones: contain three varieties of iodopsin, which can detect color & are more active in bright light

Front 27

Where are cones highly concentrated?

Back 27

Fovea

Front 28

Describe interactions in the retina

Back 28

Light energy stimulates photoreceptor cells, which stimulate bipolar cells

Many photoreceptors converge on one bipolar cell

Photoreceptors also stimulate interneurons which signal (usually in an inhibitory manner) surrounding bipolar cells

As a result, the photoreceptor that receives the greatest light energy stimulus will stimulate one bipolar cell and, through lateral inhibition (involving interneurons), decrease the stimulation of surrounding bipolar cells

As a result, the brain receives messages of light contrasts or comparisons from 2 biipolar cells that represent neighboring pitns in the visual field

Front 29

Bipolar cells stimulate ______ cells, whose _____ form the _____ _____ that extends into the brain

Back 29

Ganglion cells
Axons
Optic nerve

Front 30

Stimulation of which cells enhances the sensation of variations?

Back 30

Ganglion cells

Front 31

Why do we have a blind spot in our eye?

Back 31

There are no photoreceptors at the point where the optic nerve leaves the eye

Front 32

What happens at the optic chiasm?

Back 32

Fibers carrying info about the R side of the visual field cross over to the L side of the brain

Front 33

Retinotopy

Back 33

topographical organization of the image is maintained all the way back to the cortex like a map

Front 34

accommodation

Back 34

lens adjusts itself so that what you're looking at is in focus

Front 35

Object is farther away your lens becomes _______

Back 35

Fatter

Front 36

Describe nearsightedness

Back 36

Eyeball is too long

Front 37

Colorblindness

Back 37

absence of gene for short, medium, or long-wavelength cones