Perception

Question 1

Horace Barlow (1921)?

Answer 1

Chief Proponent of Physiological response

Question 2

What does the physiological approach to perception suggest?

Answer 2

That understanding neurones and how they react to perceptual stimuli (and eachother) is the way to understand perception

Question 3

What are main techniques used to study the physiologial approach to perception?

Answer 3

Single unit electrophysiology. Psychophysics, Neuroimaging

Question 4

Top down perception?

Answer 4

processing based on previously acquired knowledge

Question 5

Example of top down perception?

Answer 5

“brainstorm / Green Needle” viral video

Question 6

Bottom Up Processing?

Answer 6

Processing based on the stimuli reaching the receptors

Question 7

Ecological approach?

Answer 7

Little to be gained from lab experiments, experiments must be done in the real world

Question 8

Chief proponent of ecological approach?

Answer 8

James Gibson (1904 - 1979)

Question 9

Theories of perception?

Answer 9

Physiological approach (indirect), Ecological Approach, (direct), Computational approach (indirect)

Question 10

Measuring Perception - The phenomenological approach

Answer 10

describing what you see / feel etc. Similar to introspection with wundt, except focusing more on external stimuli

Question 11

Absolute threshold?

Answer 11

Smallest amount of stimulus energy necessary for an observer to detect a stimulus

Question 12

What is the method of limits?

Answer 12

A method to measure absolute threshold, zoom in on absolute threshold, moving above and below it less and less

Question 13

What is method of adjustment?

Answer 13

A crude method, requires the participant to change the intensity and say when they can sense something

Question 14

Staircase method?

Answer 14

Usually begins with high intensity stimulus, then reduces down until participant cannot sense it, which then reverses directions and again, each point then gets averaged

Question 15

JND?

Answer 15

Just Noticeable Difference

Question 16

Weber’s Law

Answer 16

the ratio of the JND to the standard stimulus is constant

Question 17

ΔI/I = k

Answer 17

The formula of Weber’s Law

Question 18

What is the formula of Weber’s Law?

Answer 18

ΔI/I = k.

Question 19

Magnitude estimation?

Answer 19

When subjects assign magnitude estimations to stimuli, their perception of magnitude is not accurate

Question 20

advantage of observational studies in perception?

Answer 20

more ecologically valid

Question 21

Who is the chief proponent of the ecological approach to perception?

Answer 21

James Gibson (1904-1979)
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Question 22

computational approach?

Answer 22

perception is information processing, transformation of sensory data from one form to another

Question 23

Gross anatomy of the visual system?

Answer 23

the retina, with rods and cones almost at the back of the retina. Optic nerves lie closest to the pupil

Question 24

What are the cells between the optic nerve and rods and cones?

Answer 24

Ganglion cells and blood vessels, bipolar and amacrine cells, then rods and cones

Question 25

Which way do the outer segments of the rods and cones face?

Answer 25

away from the pupil

Question 26

The receptive field is?

Answer 26

the region of retina, which, when stimulated, influences the firing rate of a neurone.

Question 27

Phototransduction is?

Answer 27

The process of tranforming light energy into electrical signals

Question 28

What is the first step of phototransduction?

Answer 28

photons of light are absorbed by the pigments in the rods and cones

Question 29

What are the pigments in the outer segment of rods?

Answer 29

Rhodopsin

Question 30

What do the photons do to the pigments in the rods and cones?

Answer 30

They force them to isomerise

Question 31

What does isomerise mean?

Answer 31

this means that the molecules change shape, putting the molecule in an active state

Question 32

What does activating the pigment in the receptors do?

Answer 32

triggers an enzyme cascade, eventually triggering an electrical response, in the photoreceptor

Question 33

What are retinal ganglion cells?

Answer 33

type of neuron located near the inner surface (the ganglion cell layer) of the retina. receives signals from receptors, the more stimulation, the increased firing rate

Question 34

What do retinal ganglion cells respond best to?

Answer 34

Contrast between the centre of that visual field and the surround, finding 'intensity edges'

Question 35

What is the optic chiasm?

Answer 35

the crossover in the brain, where the optic nerves partially cross, located below the hypothalamus

Question 36

The lgn is?

Answer 36

The lateral geniculate nucleus

Question 37

What is the structure if the LGN?

Answer 37

a bilateral nucleus with 6 layers. 1,4,6 from contralateral eye. 2,3,5 from ipsolateral eye.

Question 38

How is the LGN organised?

Answer 38

Retinotopically, the organsiation of the LGN largely reflects the organisation of the visual field

Question 39

Why do optic nerves partially cross?

Answer 39

so the right hemisphere has all the information from the left visual field and vice versa.

Question 40

Cells in different layers of the LGN that line up will...

Answer 40

have receptive fields in the same area

Question 41

What is the shape of the receptive fields that report back to the LGN?

Answer 41

concentric

Question 42

What type of cells are found in layers 1 and 2 of the LGN?

Answer 42

large bodied cells (magnocellular)

Question 43

what do magnocellular cells largely do?

Answer 43

they have monochromatic responses, so mediate responses between light and dark

Question 44

What type of cells are found in layers 3-6 of the LGN?

Answer 44

parvocellular cells, that mediate colour vision

Question 45

why must there be some convergence involved in retinal function?

Answer 45

There are only 1 million axons in the optic nerve, yet are 120 million cones and 6 million rods, so there must be convergence

Question 46

Which cells are responsible for convergence of signals from rods and cones?

Answer 46

horizontal and amacrine cells

Question 47

what is visual electrophysiology?

Answer 47

Experiments (usually on animals) where tiny electrodes are placed close to or inside a visual neurone

Question 48

What is the method of visual electrophysiology

Answer 48

animals are usually anaesthetised and paralysed, visual stimuli is presented whilst electrical signals are recorded