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PSYC 445 Phillips > Module 2 > Flashcards

Module 2 Flashcards

1
Q

What does mass action refer to?

A

The idea that a greater amount of damaged area will lead to a greater deficit

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2
Q

What are some methods for studying how the brain works?

A
  1. the lesion method

2. the general approach

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3
Q

Describe the lesion method. How does it work? Which participants can be included in research?

A

The lesion method assumes that damage to a certain brain region can help us infer the function of that region by observing the resulting deficit

  • this, however, does not allow us to extrapolate on how this brain area mediates a function; it simply tells us that it does
  • participants who have experienced some sort of brain trauma are all possible candidates for research, as well as animals who have had their brains damaged manually
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4
Q

What is double-dissociation?

A

This tries to show that damage to area A impairs function X but not Y, and damage to area B impairs function Y but not X

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5
Q

What might double-dissociation suggest?

A

That different modules are independent and depend on different regions of brain tissue

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6
Q

What is telegraphic speech?

A

A trait that is sometimes observed in patients with Broca’s aphasia - sentences are stripped down to the bare minimum to convey a message

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7
Q

Describe the general approach?

A

It is a comprehensive, broad assessment of cognitive function to determine what further tests need to be done

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8
Q

What is the MoCA?

A

The Montreal Cognitive Assessment

- it is a screening tool for mild cognitive impairment, which can indicate the future development of Alzheimer’s Disease

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9
Q

What did patient HM contribute to our knowledge of how the brain works?

A

HM underwent a hippocampal surgery and then it was observed that they had severe memory deficits - they could not remember significant life events such as the death of a parent, and they were unable to form new memories
- this is an example of how the lesion method can help us understand the functionality of the brain

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10
Q

Since HM, what have we learned in addition to memory concerning the hippocampus?

A

Damage to the left hippocampus causes verbal deficits and damage to the right hippocampus leads to non-verbal and spatial deficits

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11
Q

When do we use single-case studies?

A

We use single cases to narrow down assumed function, as well as to perform screening tests

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12
Q

When do we use group studies?

A

When we notice a pattern of behaviour in people who have similar types of brain damage to similar areas

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13
Q

What is a major con of using single-case studies?

A

The results are not generalizable to the population

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14
Q

What are some cons with using group studies?

A

The size and severity of the lesion, as well as individual differences could have an impact on the resulting behaviour

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15
Q

What is the critical window?

A

The stage at which a brain function stops developing

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16
Q

What are some examples of variability in types of brain damage?

A
  1. head trauma: did it penetrate or was it due to impact?
  2. tumours: did the surgeon damage other areas when it was removed? Did the tumour put pressure on other brain regions?
  3. neurodegenerative disorders, surgical lesions, carbon monoxide poisoning, stroke, etc…
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17
Q

What is a stroke caused by?

A

Blockage in one of the cerebral arteries

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18
Q

What are the three cerebral arteries? Where do they supply blood to?

A
  1. anterior cerebral artery - affects medial brain
  2. middle cerebral artery - affects everywhere
  3. posterior cerebral artery
19
Q

What are the benefits of using human subjects over animals?

A

Hypotheses are generated from single cases of humans, and we are able to test these hypotheses with group studies

20
Q

Why might we want to use animal models instead? What can be a con of using them over humans?

A

Animals have highly selective regions, but we are unable to examine uniquely human abilities

21
Q

What are some limitations of the lesion method?

A
  1. acute vs. chronic effects
  2. sparing of function - when the damage occurs in the patient’s life can influence the effect of the lesion
  3. location and amount of damage is very variable
  4. etiology (how it happened) impacts the result
  5. premorbid ability (what they were able to do before)
  6. cognitive reserve (people who have a higher education level protect themselves in a way more so than people with less education)
  7. observation of function is indirect (there can be many other brain areas that participate in the function, or alternate brain areas due to reorganization of function
22
Q

What is the give and take between the lesion method and neuro imaging?

A

Neuro imaging can tell us the area, but not its critical function, and the lesion method can tell us a critical function, but not exactly where

23
Q

What does CT/CAT scan stand for?

A

Computerized Tomography and Computerized Axial Tomography

24
Q

When were CT and CAT scans first made available?

A

in the 1970s

25
Q

Describe the premise behind CT and CAT scans?

A

The premise of creating an image is based on the knowledge that tissues of different densities can absorb x-rays to differing degrees
- thus, bone (which has a high density) absorbs more x-ray (and therefore appears white) compared to the brain (which has a lower density, absorbing less x-ray, making it appear to be grey)

26
Q

How do MRI machines work?

A

The magnetic field lines up the hydrogen protons in the brain, and then sends a separate pulse of magnet, causing the protons to relax and then realign - the time it takes for the protons to relax is measured, as well as how quickly the protons go out of sync (to dephase)

27
Q

What does a T1 weighted MRI focus on?

A

Realignment; used to see grey and white matter (thus it has a high spatial resolution)

28
Q

What does a T2 weighted MRI focus on?

A

Dephasing; used to detect pathology in the brain, including demyelination of axons

29
Q

How can structural imaging help researchers answer questions?

A

They can examine the differences in individuals with certain skills or deficits to answer their questions, based on structural differences

30
Q

What is diffusion tensor imaging?

A

It images the direction and diffusion of water in the white matter plane - this helps us to see projections of fibres and targets

31
Q

What do the colours in DTI represent?

A 
Red= projection in the left/right modality
Blue = top/bottom modality
Green = Front/back modality
32
Q

What are some advantages to using MRI?

A
  • No ionizing radiation
  • high spatial resolution
  • non-invasive
33
Q

What are some disadvantages to using MRI?

A
  • expensive ($500/hour)
  • claustrophobic
  • long scan times
  • cannot scan patients with metal in them, or pregnant women
  • noisy (can affect auditory scans)
34
Q

What does phase refer to in MRI language?

A

The protons have the same temporal properties

35
Q

What is amyloid?

A

Abnormal protein that can contribute to Alzheimer’s

36
Q

Why is PET considered a functional scan?

A

Because it images blood flow

- the hypothesis is that areas that are more active have greater metabolic needs and therefore require more blood

37
Q

Describe how PET scans work?

A
  1. radioactive isotopes are injected into the blood (different tracers can map different things, such as oxygen, blood flow, neurotransmitters, etc
  2. the injected isotopes decay and then emit gamma rays (gamma ray detectors surround the head and trace where the annihilation event occurred)
38
Q

What do warmer colours mean on a PET scan mean?

A

More activity to that brain area

39
Q

Describe the subtraction technique

A

Designed to be different from control in only one variable so that researchers can imply A-B
- subtract stimulation condition from baseline condition and compare brain regions that are different

40
Q

What are the advantages of using PET?

A
  • it is a functional technique

- can help with neuropsychiatry research

41
Q

What are the disadvantages of using PET?

A
  • complex and costly
  • poor temporal resolution (1-40 minutes)
  • poor spatial resolution (need to co-label with MRI scan)
  • multiple scans are problematic
42
Q

What is the brain reserve hypothesis?

A

More brain tissue leads to more resilience to pathoogy

43
Q

What is the cognitive reserve hypothesis?

A

A greater amount of connections between brain areas can help with resilience to pathologies

PSYC 445 Phillips (13 decks)

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