Processing the Environment

Question 1

Visual Cues

Answer 1

Depth, Form, Motion, & Constancy

Question 2

Binocular Cues

Answer 2

retinal disparity= eyes are 2.5 inches apart & convergence= things far away, eyes are relaxed. Things close to us, eyes contract

Question 3

Monocular Cues

Answer 3

relative size, interposition (overlap), relative height (things higher are farther away), shading and contour, motion parallax (things farther away move slower).
Constancy: our perception of object doesn’t change even if it looks different on retina (ex: size constancy, shape constancy, color constancy)

Question 4

Hearing

Answer 4

inner ear muscles: higher noise= contract

Question 5

Touch

Answer 5

temperature receptors desensitized

Question 6

Smell

Answer 6

desensitized to molecules

Question 7

Proprioception

Answer 7

mice raised upside down would accommodate over time, and flip it over

Question 8

Sight

Answer 8

down (ex: light adaptation, pupil constrict, rods and cones become desensitized to light) and up regulation (dark adaptation, pupils dilate)

Question 9

Weber’s Law

Answer 9

2 vs 2.05 lb FEEL the same and 2 vs 2.2 weight difference would be noticeable.
The threshold at which you’re able to notice a change in any sensation is the just noticeable difference
Linear relationship between incremental threshold and background intensity

Question 9

Vestibular System

Answer 9

balance and spatial orientation
focuses on inner ear –> semicircular canals (posterior, lateral, and anterior)
canal filled with endolymph and causes it to shift and detects what direction our head is moving in and the strength of rotation
contributes to dizziness and vertigo

Question 9

Absolute threshold of sensation

Answer 9

minimum intensity of stimulus needed to detect a particular stimulus 50% of the time.
low levels of stimulus, some subjects can detect and some can’t
influenced by: expectations, experience, motivation, alertness
Subliminal stimuli: stimuli below the absolute threshold

Question 10

Otolithic organs

Answer 10

utricle and saccule help detect linear acceleration and head positioning. Lying down to standing up, they move and pull on hair cells which triggers AP

Question 10

Signal Detection Theory

Answer 10

how we make decision under conditions of uncertainty – discerning between important stimuli and unimportant “noise”

Question 11

Bottom-Up Processing

Answer 11

stimulus influences our perception
processing sensory information as it is coming in (built from smallest piece of sensory information, memories and experiences)

Question 12

Top-Down Processing

Answer 12

background knowledge influences perception
Ex: Where’s Waldo.
Driven by cognition (brain applies what it knows and what it expects to perceive and fill in blanks)

Question 13

Gestalt Principles

Answer 13

Similarity (items similar to one another grouped together), Pragnanz (reality is often organized reduced to simplest form possible), Proximity (objects that are close are grouped together), Continuity (lines are seen as following the smoothest path), Closure (objects grouped together are seen as a whole)

Question 14

Conjunctiva

Answer 14

first layer light hits

Question 15

Cornea

Answer 15

transparent thick sheet of tissue

Question 16

Anterior Chamber

Answer 16

space filled with aqueous humor, provides pressure to maintain shape of eyeball

Question 17

Pupil

Answer 17

hold made by iris (determines eye color)

Question 18

Lens

Answer 18

bends the light so it goes to back of eyeball

Question 19

Suspensory ligaments

Answer 19

attached to a ciliary muscles. these form the ciliary body which secretes the aqueous humor

Question 20

Posterior Chamber

Answer 20

area behind ciliary muscles, also filled with aqueous humor

Question 21

Vitreous Chamber

Answer 21

filled with vitreous humor, jelly-like substance to provide pressure to eyeball

Question 22

Retina

Answer 22

filled with photoreceptors.
Macular= special part of retina rich in CONES
Fovea- completely covered in cones, no rods

Question 23

Choroid

Answer 23

pigmented black in humans, a network of blood vessels. Bc black all light is reflected

Question 24

Sclera

Answer 24

whites of the eye, thick fibrous tissue that covers posterior 5/6th of eyeball. Attachment point for muscles

Question 25

Sensation

Answer 25

light–> neural impulse, by a photoreceptor

Question 26

Light

Answer 26

electromagnetic wave part of a large spectrum
EM spectrum contains everything from gamma rays to AM/FM waves. Visible light is in the middle (violet (400 nm) and red (700 nm))
Sun is most common source of light
Light enters pupil and goes to retina which contains rods and cones

Question 27

Rods

Answer 27

120 million rods, night vision
light comes in, goes through pupil, and hits rod. Normally rod is turned on, but when light hits turns off
When rod is off, it turns on a bipolar cell, which turns on a retinal ganglion cell, which goes into the optic nerve and enters the brain

Question 28

Cones

Answer 28

6-7 million, red, green, blue, covered in fovea

Question 29

Phototransduction Cascade

Answer 29

when light hits rods and cones
as soon as light is presented, takes light and converts it to neural impulse. Normally turned on but when light hits it is turned off

Question 30

PTC steps

Answer 30

Inside rod LOTS OF DISKS
Proteins in disks: rhodopsin contains small molecule call retinal. When light hits it can hit the retinal and cause it to change conformation from bent to straight
Retinal changes shape, rhodopsin changes shape

Question 31

Cascade of events

Answer 31

Transducin= alpha, beta, gamma
Breaks from rhodopsin and alpha part comes to disk and binds to phosphodiesterase

PDE takes cGMP and coverts to regular GMP. Na+ channels allow Na+ ions to come in but for this channel to open, need cGMP bound and as cGMP decreases, Na channels close

Less Na+ enters the cell, rods hyperpolarize and turn off. Glutamate no longer released and no longer inhibits ON bipolar cells (it’s excitatory to OFF bipolar cells)

Bipolar cells turn on and this activates retinal ganglion cell which sends signal to optic nerve to brain

Question 32

Photoreceptors

Answer 32

specialized nerve that takes light and converts to neural impulse
Inside rod optic discs that are large membrane bound structures and have proteins that fire APs to the brain

Question 33

Proteins

Answer 33

Rods= rhodopsin and cones= photopsin

Question 34

Differences b/w rods and cones

Answer 34

120 mil rods vs 6 mil cones
Cones concentrated to fovea
Rods are more sensitive to light than cones and better at detecting light
Cones less sensitive but detect color (60% red, 30% green, and 10% blue)
Rods have slow recovery time, cones have faster recovery time. Takes a while to adjust to dark, rods need to be reactivated

Question 35

Photoreceptor Distribution in Retina

Answer 35

optic nerve connects to retina at BLIND SPOT- no cones or rods
rods found in periphery and cones in fovea
Zoom in on fovea- no axons in way of light so higher resolution
If light hits periphery, light has to go through bundle of axons and some energy lost. At fovea light hits cones directly

Question 36

Visual Field Processing

Answer 36

all right visual field goes to left side of brain, all left visual field goes to right side of brain

Question 37

Feature Detection and Parallel Processing

Answer 37

Color (cones, trichromatic theory of color vision), form (parvocellular pathway- good at spatial resolution but poor temporal), motion (magnocellular pathway, has high temporal resolution and poor spatial resolution, no color)
Parallel processing: see all at same time; simultaneous processing of incoming stimuli that differs in quality