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Psycho Perception > Imaging > Flashcards

Imaging Flashcards

1
Q

classical cognitive approach involves 3 things

A
  1. measuring observable behavior
  2. making inferences about underlying cognitive activity
  3. consider what the behavior says about how the mind works
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2
Q

what does imaging introduce

A

whole range of objectively measurable things that we can now incorporate into our investigations

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3
Q

Cognitive neuroscience approach involves 3 things

A
  1. measuring neural activity (and/or observable behavior)
  2. making inferences about underlying cognitive activity
  3. consider what the neural activity (and or behavior says about how the mind works
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4
Q

3 important considerations relevant for conducting/interpreting imaging work?

A
  1. Theoretically meaningful interpretations can be complicated
  2. Analyses often rely on subtractive logic, which may obscure meaningful information (e.g. what’s happening with the default network)
  3. Localization of function is often assumed but may sometimes be an oversimplification
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5
Q

within Theoretically meaningful interpretations something emerges

A
  1. Many confounds can emerge (e.g. false positive, which can become much more likely if you don’t adequately correct for multiple comparisons)
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6
Q

false positives can sometimes occur when

A

there is a large volume of data

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7
Q

statistical problem of multiple comparisons (what type of error)

A

, the more comparisons you make between various data points, the more likely you are to find a statistically significant result purely by chance (type 1)

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8
Q

Subtractive logic (mental chronometry) is used

A

used to make inferences about the differing time courses of various cognitive processes

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9
Q

Subtractive logic in neuro imaging (3 steps)

A
  1. measure activity at rest (baseline activation)
  2. measure brain activity during task (task activation)
  3. subtract baseline from activation
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10
Q

potential problem with subtractive logic

A

our brains are constantly active and that baseline activity may actually reflect processes that you don’t fully understand… if so, you may be ‘subtracting the background’, which doesn’t always make sense to do

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11
Q

default mode network (DMN)

A

a network of brain regions that are active at rest

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12
Q

properties of default mode network

A

Evidence for some form in many different mammals, Associated with mind wandering in humans, May have other adaptive functions (e.g. memory consolidation

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13
Q

localization of function

A

the idea that we have specific brain regions (or networks) that are specialized for certain kinds of processes

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14
Q

Phrenology

A

A belief system that attempted to relate variation in the shape of different parts of the skull with behaviour and cognition

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15
Q

mass action

A

proposed that specific functions were in fact not localized to particular parts of the brain

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16
Q

equipotentiality

A

which assumes any chunk of cortical tissue has the potential to support any brain function

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17
Q

plasticity

A

tissue in different parts of the brain can ‘take over’ for other damaged parts and effectively relocate functions, albeit there are limitations

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18
Q

pioneers who used EEG

A

Herbert Jasper

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19
Q

imaging methods with high spatial resolution

A

fMRI, PET

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20
Q

imaging methods with high temporal resolution

A

EEG/ERP, MEG

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21
Q

Electroencephalogram (EEG)

A

provides an overall measure of electrical activity emanating from the brain on the basis of the signal that reaches electrodes placed on the scalp

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22
Q

human brainwaves (5) from highest frequency to lowest

A

gamma, beta, alpha, theta, delta

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23
Q

application for EEG

A

screening for seizure activity

24
Q

Event-Related Potentials (ERPs)

A

using EEG to measure average characteristic changes in electrical activity associated with particular psychological events (e.g. a stimulus presentation)

25
Q

Calculation of ERP requires

A

signal averaging to form a grand average for multiple subjects across many trials that is time-locked to a specific event

26
Q

ERP naming conventions have two parts

A

a letter and a number

27
Q

The letter(s) used in ERPs

A

N - negative deflection P-positive deflection

28
Q

The number for ERPS

A

1,2…100 depending on how many milliseconds after the time-locked event (e.g. stimulus presentation) before the component typically appears

29
Q

application of ERPs

A

The presence/absence of a particular kind of ERP in response to an event can be informative, though the timing and/or magnitude of the ERP elicited is often more informative…Smaller amplitude and/or delayed onset of an ERP could indicate diminished or impaired processing

30
Q

Magnetoencephalography (MEG)

A

maps subtle changes in the magnetic fields around the scalp caused by fluctuations in electrical activity in the brain

31
Q

Magnetoencephalography (MEG) can also measure

A

ERPs

32
Q

MEG characteristics (positive)

A

More sensitive to EEG

33
Q

MEG characteristics negative

A

expensive, requires a completely magnetically shielded room, etc

34
Q

Magnetic Resonance Imaging (MRI)

A

uses magnetic fields and radio waves to generate anatomical images of body tissue

35
Q

Functional Magnetic Resonance Imaging (fMRI)

A

measures changes in the BOLD signal (blood-oxygen-level-dependent signal), which is correlated with cognitive activity

36
Q

Remember that the BOLD signal is

A

simply a correlate of neural activity, it is not a direct measurement of it!

37
Q

Voxles

A

imaginary boundaries based on three-dimensional pixels

38
Q

fMRI analyses ‘draw’

A

what we can think of as imaginary boundaries based on three-dimensional pixels (voxels) that are superimposed onto the brain

39
Q

what does the BOLD signal tell us

A

provides estimates for changes in the average/overall activity within specific voxels

40
Q

Positron Emission Tomography (PET)

A

the injection of radioactive 2-DG (structurally similar to glucose) that is rapidly taken up by active cells until gradually breaking down

41
Q

How does the PET use radioactive glucose to measure brain activity

A

can see where the radioactive dye is being used in the brain

42
Q

implications of using either high spatial or high temporal imaging (the tradeoffs)

A

each kind of measure their own thing…there is some overlap in the modes of measurement but for the most part there is not one specific test that captures it all

43
Q

seed location

A

brain location associated with a specific task

44
Q

Diffusion Tensor Imaging (DTI)

A

uses MRI technology to map out major pathways (tracts: bundles of axons) in the brain

45
Q

Transcranial Magnetic Stimulation (TMS)

A

uses a magnetic field and an electrical current to modulate brain activity at specific sites (generally decreasing or increasing firing)

46
Q

what type of imaging can create a virtual leison

A

TMS

47
Q

Repetitive TMS (rTMS)

A

can produce longer lasting changes in neuronal activity, though there is still some debate about the safety and efficacy of this method

48
Q

Magnetic Resonance Spectroscopy (MRS

A

uses an MRI machine to produce estimates related to metabolic changes in the brain

49
Q

what does using Magnetic Resonance Spectroscopy (MRS) allow?

A

estimates related to the chemical composition in particular brain regions, and has applications for both basic research and clinically relevant purposes

50
Q

major advantage to using MRS

A

that it can be used to produce in vivo (i.e. within a living organism) estimates related to some simple neurotransmitters (e.g. GABA and glutamate)

51
Q

major disadvantage to using MRS

A

, it is not capable of measuring more (chemically) complex neurotransmitters that are of interest of cognitive neuroscientists (e.g. serotonin, dopamine)

52
Q

optogenetics

A

involves genetically engineering neurons that are light-sensitive (e.g. ion channels that open when exposed to a particular wavelength)
This allows neurons to be effective controlled, or turned on/off, by exposing them to light

53
Q

Functional Near-Infrared Spectroscopy (fNIRS)

A

relatively cheap, non-invasive method for estimating changes in neural activation

54
Q

How is Functional Near-Infrared Spectroscopy (fNIRS) done

A

measures reflected light from hemoglobin so, Changes in the relative proportion of light that is reflected back can therefore be used to estimate changes in hemoglobin concentration (which can, in turn, be used to infer changes in neural activation)

55
Q

case study advantage, disadvenatage

A

advantage - unique research opportunities, disadvantage. cant generalize to the general public

56
Q

Lesion studies

A

involve training a non-human animal to perform a task, damaging a part of the brain, then observing how that damage affects the organism’s ability to perform the previously learned task

57
Q

Advantage and disadvantage to lesion studies

A

advantage - relatively straightforward causal inferences to be made about the contribution of various brain regions
disadvantage - difficulty in generalizing observations from non-human animals to humans

Psycho Perception (10 decks)

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