Perception Flashcards

1
Q

What does the Electroencephalography (EEG) detect?

A

electrical activity
An active brain produces electrical
activity
* Event-related potentials (ERP)
* EEG measures activity in a large
group of neurons at a certain
times
* Provides great estimate of when the
brain is active

Good at timing (temporal resolution)

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2
Q

What does the Functional Magnetic Resonance Imaging (fMRI) detect?

A

energy

  • An indirect measure as it measures blood flow and not neural activity

Active brain areas need oxygen (metabolic
energy)
* A magnet detects changes in oxygenated
blood

Provides good spatial resolution but not good temporal. Also relies on the assumption more oxygen is more activity.

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3
Q

What do the Brain stimulation techniques detect?

A

change

Transcranial Magnetic Stimulation (TMS)
* Focal magnetic field induces
electricity and affects neurons in
the targeted area as well as
connected brain circuits

(?) TMS may improve memory (?)

Good to test causality (testing direct effects
of temporary lesion or stimulation on
cognition)
* fMRI and EEG are correlational
(associate brain activity to task)
* But stimulation techniques have broad
effects on the brain, so it is hard to localize
effects
* The way it works is not entirely clear

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4
Q

What are Exteroceptive sensations?

A
  • Any form of sensation that results from stimuli located outside the
    body detected by sensory organs

(Five Senses)

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5
Q

What are the Interoceptive sensations?

A
  • Sensations from inside our body
  • Proprioception: Sense of where our limbs are in space
  • Nociception: Sense of pain due to body damage
  • Equilibrioception: Sense of balance
  • Dancers have increased interoceptive accuracy
    (Christensen et al., 2017)
  • Finding was dancers could estimate heart rate more accurately
    than non-dancers
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6
Q

What is Proprioception?

A

Sense of where our limbs are in space

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7
Q

What is Nociception?

A

Sense of pain due to body damage

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8
Q

What is Equilibrioception?

A

Sense of balance

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9
Q

What is Synesthesia?

A

A neurological condition in which
one sense automatically triggers
the experience of another sense
* Hear colours
* Smell sounds
* See time
* Genetic component
* More common in women
* Specific pairings tend to be stable
over the lifetime of the individual

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10
Q

What is Grapheme-colour synesthesia:?

A

Colour with letter/numbers
“7 is pale blue with a pleasant, soft, nice personality”

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11
Q

What is Chromesthesia?

A

Sound can evoke an experience of colour

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12
Q

Why is synaesthesia important?

A

1) Shows the importance of Individual differences

2) Shows the communication and crossing of circuits that happen in the brain

Ex. fMRI studies show activating of V4 color processing region during
words for grapheme–colour synaesthetes

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13
Q

What is Early visual processing?

A
  • Sensation
  • Eyes and the optic nerve
  1. Light waves enter the eye
    * Projected onto the retina
    * The retina forms an inverted image
    *Later processes turn this image around
  2. Retina photoreceptors convert light to
    electrical activity
    * Rods: low light levels for night vision
    * Cones: high light levels for detailed color vision
  3. The electrical signal is sent to bipolar
    cells
    * Sent on to the ganglion cells
  4. The signal exits through the optic
    nerve
    * To the brain for later visual processing
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14
Q

What is Late visual processing?

A
  • Perception
  • The visual cortex or
    occipital lobe
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15
Q

What is Information compression in the visual system?

A

Millions of photoreceptors in each retina converge onto 100x fewer ganglion cells -> optic nerve -> brain
* Input from the eyes to the brain is compressed

  • Hot take: You don’t ‘see’ everything that is out there in the
    world
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16
Q

What is the distribution of photoreceptors in the brain?

A
  • Cones are concentrated in the
    fovea
  • Small area on the the central part of
    the visual field
  • Thus, center of your visual field is
    most detailed
  • Rods are mostly in the periphery
  • Thus, periphery of your visual field is
    less detailed and less accurate
17
Q

What is Perceptual Filling-In

A

When we focus with our cones on something, we tend to fill in the background of things we aren’t focusing on (with rods)

18
Q

Why do we have a Blindspot?

A

Photoreceptors are at the back
of the retina (farther from the
‘world’); Ganglion cells are at the
front

  • Ganglion cells make up the
    optic nerve that exits to the brain
  • Must past the photoreceptor
    layer
  • At this ‘exit location’, there are
    no photoreceptors
  • No vision!
19
Q

Why dont we usually see our blindspot?

A
  • Perceptual filling-in
  • Later visual processes in the brain provide the missing
    information by ‘interpolating’ visual information (e.g.,
    colors) from surrounding areas
  • The left and right visual fields can compensate for each other’s blindspot
20
Q

What does the thalamus do with vision?

A

(lateral geniculate nucleus,
LGN) is the way-station

(All senses but smell stop here first)

21
Q

Does vision have Contralateral representation?

A

Yes !

(Left visual field is perceived via the
right hemisphere
* Right visual field is perceived via the
left hemisphere)

22
Q

How does the Primary Visual Cortex process information?

A

Specialized regions that process
specific visual attributes or features
* Edges
* Angles
* Color
* Light

23
Q

What do Visual Association Areas do?

A

interpret visual signal, assigns meaning

24
Q

Explain the What (ventral) pathway?

A

Occipital to temporal lobes
* Shape, size, visual details

25
Q

Explain the Where (dorsal) pathway

A
  • Occipital to parietal lobes
  • Location, space, movement information
26
Q

What happens when Ventral damage with intact dorsal stream?

A
  • Impaired performance on visual object recognition or matching tasks
27
Q

What happens when Dorsal damage with intact ventral stream?

A
  • Accurate performance on object recognition or matching tasks
  • Impaired performance on visual guided action (picking up an
    object appropriately)
28
Q

What is Bottom-up processing?

A

the influence of information from the
external environment on perception
* Information from the sensory organs (eyes) to the visual cortex

29
Q

What is Top-down processing?

A

the influence of knowledge
(expectations, context and goals) on perception
* Information from higher processing brain regions (prefrontal
cortex or higher visual processing areas) is sent back to the
sensory organs

30
Q

What is the Constructivist Theory of Perception?

A
  • We use what we already know
    and expectations to predict how
    to perceive sensory information
  • Relies on the influence of topdown processes to vision
  • Illustrates how perception is an
    “illusion”
31
Q

Explain the Ponzo illusion

A

depth perception

32
Q

What is the The letters in context effect?

A

The ability to read words in sentences even when the letters in the middle
of some of the words are mixed up

You can stlil raed this senetnece even thuogh lettres in the wrods are
jubmled.

  • You ‘expect’ to see real words in a sentence
  • This is why it is hard to edit your own work
33
Q

What is the color in context effect

A
  • The context a color appears changes how you see that color.
  • Color perception depends on :
  • The wavelengths of light that fall on our retina
  • Our expectation (from experience) of how objects look under
    contexts of illumination

Darker backgrounds (make object look brighter)
Light backgrounds (make object look darker)

34
Q
A