introduction to sensation and perception Flashcards

Lecture 2/22

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1
Q

define sensation

A

registering stimulation of the senses

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2
Q

define perception

A

processing and interpreting sensory information

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3
Q

define cognition

A

using perceived information to learn, classify and comprehend

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4
Q

fundamental concepts - electromagnetic energy

A

links to eyes

photoreceptors

primary visual cortex

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5
Q

fundamental concepts - chemical composition

A

links to tongue and nose

chemoreceptors

gustatory cortex and olfactory cortex

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6
Q

fundamental concepts - air pressure waves

A

links to ears

mechanoreceptors

auditory cortex

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7
Q

fundamental concepts - tissue distortion

A

links to touch/ nerves

mechanoreceptors and thermoreceptors

somatosensory cortex

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8
Q

fundamental concepts - gravity and acceleration

A

links to body/ movement
e.g. handstand

mechanoreceptors

temporal cortex

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9
Q

define transduction

A

conversion of environmental energy to nerve signals

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10
Q

feedback reception

A

a top down process - going backwards through the sections below. (not via thalamus for smell)

environmental stimulus, receptors, intermediate neurons, thalamus neuron,
primary visual cortex, secondary associative cortex, higher cortex

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11
Q

bottom up processing

A

perception starts with the physical characteristics of stimuli and basic sensory processes

e.g. feature detectors

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12
Q

gibson - direct perception 1950

A

links to bottom up processing

the information coming from sensory receptors is enough for perception to be rich and detained - complex mechanisms are not necessary
the environment contains sufficient cues to provide context to aid perception
e.g. texture can indicate depth

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13
Q

direct perception

A

gibson 1950s

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14
Q

gibson 1950

A

direct perception

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15
Q

top down processing

A

the perceiver constructs their understanding of external stimuli based on their past experience and knowledge

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16
Q

gregory 1966

A

links to top down processing

“perception is not determined simply by stimulus patterns; rather it is a dynamic searching for the best interpretation of the available data”

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17
Q

how do we investigate sensation and perception

A
  1. straining
  2. single cell recordings = electrophysiology
  3. functional magnetic resonance imaging = FMRI
  4. Lesion studies e.g. phineas cage
  5. event-related potential (ERP) from electroencephalogram (EEG)
  6. Optical imaging / near infa-red spectroscopy (NIRS)
  7. psychophysics
  8. illusions and introsception
  9. computational modelling
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18
Q

what is single cell recording

A

action potentials of neurons recorded with mircoelectrode inserted close to cell.

single neurons can be selective for a stimulus as specific as one particular person

19
Q

how is a single cell recording completed

A

cortical recording requires section of skull to be removed

microelectrodes inserted close to a cell to see its action potential

20
Q

why is single cell recordings helpful

A

useful for identifying cells which are selective for certain features e.g. orientations, direction of motion and faces

21
Q

Quiroga et al (2009) Quiroga et al (2005)

A
  • epilepsy patients implated with depth electrodes, recording from single cell

-presented with photos, text name and spoken name of multiple people

  • selective neurons in medial temporal lobe represent individuals in multiple sensory modalities
22
Q

who research epilepsy with single cell recordings

A

Quiroga et al (2009) Quiroga et al (2005)

23
Q

lesion studies

A

can be done by
knife or neurotoxins

a knife will cut axons but a neurotoxin can only destroy nerve cells

24
Q

disadvantages of lesion studies

A
  1. ethical issues
  2. studying a faulty system - wont tell you about a healthy system
  3. brain changes in response to damage
25
Q

neuro-psychology

A

damage to brain due to stroke, trauma, road accidents, boxing etc.

26
Q

disadvantages of neuro-psychology

A

damage can be diffuse

individual variation in damage

27
Q

virtual lesions - TMS

A

Transcranial Magnetic Stimulation = TMS

  • pulses of magnetic energy disrupt activity in a small part of the brain for a short period
  • can be used to investigate sensation and perception
    e.g. biological motion
28
Q

what is biological motion

A

is the use of dots in a formation that courses the brain to see a human figure

changing the sped and location of the dots can course the brain to see different genders, weights, happiness or nervousness

29
Q

what does TMS stand for

A

transcranial Magnetic stimulation

30
Q

Grossman et al (2005) - TMS

A

TMS over posterior superior temporal sulcus disrupts biological motion

disruption of upright biological motion over PPosterior STS (right T6) but not over motion area of visual cortex (V5/MT)

31
Q

what is psycho-physics

A

quantifying relationship between physical stimuli and the psychological response

links to absolute/detection threshold and difference threshold

32
Q

what is an detection threshold

A

links to psycho-physics

smallest stimulus intensity needed for detection
e.g minimum concentration of a flavor you can taste

33
Q

what is a difference threshold

A

links to psycho-physics

smallest difference between two stimuli that can be detected - just noticeable difference -JND
e.g the minimum difference between two colours that you can see

34
Q

psycho-physics measuring thresholds

A

two alternative forced choice (2AFC)

psychometric function

35
Q

what is psychometric function

A

what is the physical response to the manipulation

36
Q

what real life issue can psycho-physics be used to study

A

can be used to find disrupted biological motion in children with autism - blake et al (2003)

37
Q

blake et al 2003 methods - psycho-physic

A

used biological motion task video - dots showing human figure
two conditions - one normal second scrambled dots

second task was global form task - had to work out with quadrant has the shape in

38
Q

blake et al 2003 - findings

A

(psycho-physics)

Autistic children show poorer performance than typically developing children for biological motion but not for form task

39
Q

example of research for psycho-physic

A

blake et al 2003

40
Q

example of visual illusions researcher

A

suchow and alvarez 2011

41
Q

the spinning dancer

A

visual illusion by Kayahara (2003)

bi-stable perception - no depth cues leads to visual ambiguity

striking individual differences in perception - is it left or right leg being stood on
individuals can learn to switch between both options

42
Q

ways that illusions can be questioned

A

introspection and systematically

43
Q

SAQ - fill in the blanks - Quiroga et al 2005 study used (i) method, investigating the (ii) brain area and showed that neurons can be selective to (iii) type of stimulus.

A

i = single cell recordings

ii = medial temporal lobe

iii= certain features e.g. orientation, direction of motion and faces