TMS and Perception (1) Flashcards

1
Q

What did Donders (1818-1889) do?

A
  • he developed mental chronometry

- he also created the reaction-time experiment

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2
Q

What is a reaction-time experiment?

A
  • measures interval between stimulus presentation and person’s response to stimulus
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3
Q

What is mental chronometry?

A
  • a measure of how long a cognitive process takes
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4
Q

What is the simple RT task?

A
  • participant pushes a button quickly after a light appears

- steps: perceive the light, generate the response

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5
Q

What is the choice RT task?

A
  • participant pushes one button if light is on the right side and another if the light is on the left side
  • steps: perceive the light, select a button to push, generate the response
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6
Q

What is the subtraction method?

A
  • Choice RT - Simple RT = Time to make a decision
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7
Q

How much longer does choice RT take compared to simple RT?

A
  • 0.1 s or 100 ms
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8
Q

What are the assumptions of the subtraction method?

A
  • assumption of serial stages: that processes are non-overlapping or parallel
  • assumption of pure insertion: that the addition of a choice does not affect length of other processes
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9
Q

According to Donders, how can mental processes be measured?

A
  • cannot be measured directly but can be inferred from a participants behaviour
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10
Q

What did Ebbinghaus do?

A
  • he created the savings curve method for studying forgetting
  • aimed to look at the contents of the mind including what’s unconsciously there
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11
Q

What is the task involved with the savings curve method?

A
  • view a series of nonsense syllables (ex. DAX or LUH)
  • repeat and predict what the next syllables will be until you can do it correctly
  • after a period of time, see if you remember
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12
Q

What do people experience when doing the savings curve method?

A
  • they have to repeat a fewer amount of times to ‘relearn’

- even if they have no conscious memory, at 31 days they have 20% savings

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13
Q

How is ‘savings’ calculated in the savings method?

A

savings = (initial reps - relearning reps) / initial reps

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14
Q

What happened during the cognitive revolution?

A
  • birth of the digital computer
  • theory of computation
  • information theory
  • computer science
  • artificial intelligence
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15
Q

What did Alan Turing do?

A
  • computability: anything that can be computed is computable by a simple “universal machine”, i.e. a Turing machine
  • to the extent that what the mind does is compute, it can be specified as a computer program
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16
Q

What did George Miller say?

A
  • I date the moment of conception of cognitive science as 11 September, 1956…”
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17
Q

What is cognitivism?

A
  • mental functions can be explained by the use of experiments following the scientific method
  • cognition consists of internal mental states whose manipulation can be described in terms of algorithms
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18
Q

What is cognitive psychology?

A
  • the scientific study of how people perceive, learn, remember and think about information
  • rejects introspection as a primary tool
  • accepts the existence of internal mental states
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19
Q

What are some famous phrenologists?

A
  • Franz Joseph Gall

- Johann Spurzheim

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20
Q

What is phrenology?

A
  • interested in how the brain relates to the mind
  • brain is the organ of the mind (not heart)
  • parts of the brain represent different faculties with the size of the part indicating the “strength”
  • studied from the outside of the brain using bumps and depressions
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21
Q

How many traits were identified in phrenology?

A
  • 27 traits
  • 19 common to human and animals (reproduction, courage)
  • 8 unique to humans (Wisdom, vanity, satire, religion)
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22
Q

Which groups opposed phrenology?

A
  • anti-localizationists: argued brain functions are an indivisible unit (brain not in sections)
  • anti-materialists: argued mental/spiritual faculties are not of organic matter (mind not tied to physical part of body)
  • both were wrong
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23
Q

What two psychologists provided evidence for localization in the 19th century?

A
  • Paul Broca’s Tan
  • Carl Wernicke
  • found specific functions to be associated with specific locations
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24
Q

What did Paul Broca observe?

A
  • speech loss not due to paralysis
  • “loss of memory of movements needed to pronounce words”
  • Broca’s area in left frontal lobe
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25
Q

What did Carl Wernicke observe?

A
  • cases of lost speech comprehension

- Wernicke’s area in left temporal lobe

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26
Q

What were the implications of Broca’s and Wernicke’s discoveries?

A
  • shift towards physiologically real functions (motor and sensory)
  • localization of higher mental functions
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27
Q

How did cognitive neuropsychology start out?

A
  • identifies the mechanisms that underlie cognition by studying the effects of brain damage
  • localizes these mechanisms to particular neural structures or processes
  • identifies the functions of brain regions
28
Q

What does cognitive neuropsychology look like today?

A
  • invention of non-invasive techniques to image the human brain
  • the most influential technique being fMRI
29
Q

How did cognitive neuroscience start?

A
  • merging of two streams
  • cognitive psychology and cognitive neuropsychology
  • measure brain function and behaviour
30
Q

Who coined the term cognitive neuroscience?

A
  • George Miller and Michael Gazzaniga
31
Q

What are the basic goals of cognitive neuroscience?

A
  • determine how the brain mediates cognition and behaviour

- relate neural structures to mental functions

32
Q

Why is measurement and manipulation a methodological issue?

A
  • Is the method measuring brain activity or manipulating it?

- What specifically is it measuring or manipulating?

33
Q

What are some safety concerns?

A
  • Is it invasive?
  • What are the risks?
  • What are the contraindications
34
Q

What is spatial resolution?

A
  • how detailed an image is

- a low resolution image will be very pixelated

35
Q

What is temporal resolution?

A
  • frames/second

- a low resolution image will look ‘jumpy’ whereas a high resolution will be smooth

36
Q

Why is fMRI so revolutionary?

A
  • in general imaging methods that are more invasive have better temporal and spatial resolution
  • fMRI has good spatial and temporal resolution despite being non-invasive
37
Q

Why are parameters a methodological issue?

A
  • need to consider what the options or settings are

- ex. ERPs: number of electrodes

38
Q

Why are experimental limitations a methodological issue?

A
  • need to consider the complications/limitations of the experimental design
  • ex. fMRI: noisy, can’t move
39
Q

Why is experimental design a methodological issue?

A
  • need to consider the typical experimental design for a certain type of measurement
40
Q

Why is data preprocessing and data analysis a methodological issue?

A
  • Need to consider what has to be done to the data before it can be analyzed
  • need to consider how data is typically analyzed
41
Q

Why is interpreting results a methodological issue?

A
  • need to consider what we can and can’t conclude
42
Q

How did transcranial magnetic stimulation (TMS) begin?

A
  • wanted to manipulate brain without invasion

- early attempts struggled to generate necessary field strength (Thompson)

43
Q

When was the first successful TMS on humans?

A
  • 1985
  • Barker et al
  • they used a smaller coil and stronger magnetic fields
44
Q

How does TMS work?

A
  • run a strong current through a coil to produce a magnetic field
45
Q

What are the types of TMS coils?

A
  • round coil
  • figure eight coil
  • double coil
  • H coil
46
Q

How does TMS stimulate the brain?

A
  • the magnetic field induces current in the brain

- in other words causes neural activity or changes in resting potentials

47
Q

Where do the strongest voltage effects occur?

A
  • for the round coil: in a circular shape that mirrors the coil
  • for the figure eight coil: between the two coils giving a more precise reading
  • the activity is localized but non-specific!!
48
Q

What is important for inducing the current?

A
  • rapid change in magnetic field, not the strength of the magnetic field
49
Q

What technology uses the same principle as TMS?

A
  • wireless (inductive) charging

- induce current in phone using coils to charge

50
Q

What are the two types of effects TMS can have?

A
  • activation/facilitation: muscle movements, phosphenes

- inhibition/disruption: impaired movement, scotomas

51
Q

What are the (physical) safety risks of TMS?

A
  • seizure induction: caused by spread of excitation
  • Hearing loss: because of loud click in the most sensitive frequency range
  • local neck pain and headaches: caused by stimulation of local muscles and nerves (particularly over fronto-temporal regions)
52
Q

When is seizure induction most risky?

A
  • for single-pulse TMS, only seizures in patients have been induced
  • with rTMS seizures can be induced in patients and normal volunteers
53
Q

What are the (psychological) safety risks of TMS?

A
  • effect on cognition: improved verbal memory, delayed recall and better motor rt
  • effect on mood in normals: dependent on site and frequency, can worsen or improve
  • long-term effects: if multiple sessions of rTMS
54
Q

What must be considered to make rTMS safe?

A
  • limit on duration based on frequency
  • ex. at 1 Hz, duration can be 1800+ s and at 25 Hz, duration can be .84 s
  • guidelines are not perfect however
55
Q

What is a motor threshold?

A
  • calibrated for each participant
56
Q

What are some contraindictions (reasons not to be a participant) for TMS?

A
  • metallic hardware
  • history of seizures
  • pregnancy
  • history of head trauma or substance abuse
  • stroke
  • brain surgery
  • other medical conditions or medications associated with seizures
57
Q

What are some guidelines to follow when administering TMS?

A
  • safety screening
  • informed consent
  • potential benefit must outweigh risk
  • equal distribution of risk (vulnerable patient populations should be avoided)
58
Q

How is TMS spatial resolution?

A
  • depends on coil shape and size
  • as good as a few millimeter for peak effect
  • peripheral areas also effected
59
Q

How is TMS temporal resolution?

A
  • single pulse TMS: about 1 millisecond!

- rTMS: depends on duration of pulse train (less than one second to greater than a minute)

60
Q

What are the parameters of TMS?

A
  • pulse sequence, frequency and duration
  • location and orientation
  • intensity (motor threshold used as a reference point)
61
Q

What are the experimental limitations of TMS?

A
  • limited stimulation depth (can’t reach medial and sub-cortical areas)
  • difficulty to localization
  • spread of activation (connected effects and paradoxical effects)
  • noise (distracting)
  • risks
62
Q

What are connected effects?

A
  • when regions are affected due to a connection to the region being stimulated
63
Q

What are paradoxical effects?

A
  • when the region that you are applying TMS to normally inhibits another region, but the TMS causes a release of the inhibition
64
Q

What are the experimental designs used with TMS?

A
  • mapping in space (virtual lesion): where things are being processed
  • mapping in time (chronometry): when things are being processed
  • may use multiple coils
  • may combine with EEG, PET, fMRI..
65
Q

How are the results f TMS interpreted?

A
  • virtual lesion: infer role by resulting deficit
  • chronometry: infer timing of neural processing
  • functional connectivity: infer connectivity between brain areas by effects of spreading activation