Research Methods Flashcards Preview

Neuroscience > Research Methods > Flashcards

Flashcards in Research Methods Deck (34)
Loading flashcards...
1
Q

What methods are used to observe brain anatomy?

A

CT and MRI

2
Q

What functioning brain imaging methods are used?

A

PET and fMRI

3
Q

List the four kinds of electromagnetic brain research methods:

A
  1. Single cell
  2. EEG
  3. ERP
  4. MEG
4
Q

Optical imaging types:

A

Fast and slow

5
Q

Method for modulating brain activity

A

TMS

6
Q

How is Positron Emission Tomography performed?

A

A radioactive substance is injected into the body - the researchers observe what parts of the brain use which molecules. It relies on the use of high energy ionizing radiation. The distribution of neurotransmitter binding is examined, providing levels of brain metabolism.

7
Q

What are the pros and cons of PET scans?

A

+ Assess many aspects of physiological function
+ Provides infor on neurotransmitter binding
+ Allows for good comparison between sample groups
- Involves the use of ionizing radiation, so cannot be used in a long term study
- Poor resolution picture
- Images are averaged over a time that is longer than the thought process

8
Q

How does Computerized Tomography work?

A

It scans the brain, creating a black and white image. The scan makes use of brain density. Black: cerebrospinal fluid < brain tissue < blood < bone : White. Hemorrhages appear lighter, due to the excess of blood.

9
Q

What are the pros and cons of CT scans?

A

+ Inexpensive
+ Can be used on almost everyone
- Poor resolution
- Use of ionizing radiation, cannot be used over long studies

10
Q

How does a Magnetic Resonance Imaging process work?

A

Magnetic fields are used to distort the bahaviour of the protons - the time it takes for the protons to return to recover from distortion creates the image.

11
Q

What are the pros and cons of MRI?

A

+ It can be used to detect different substances
+ Allows white matter tracts to be visualized via diffusion tensor imaging
+ Does not involve radiation
+ Good spatial resolution
- Can induce claustraphobia
- Cannot be used with individuals with metal not attached to hard tissue
- Expensive

12
Q

What is Diffuse Tensor Imaging?

A

It shows the direction along which water diffuses in the nerve fibres.
Direction of the water = direction of the connections
Degree of water diffusion = structural integrity of the tracts

13
Q

What is DTI often used for?

A

Investigating demyelination disorders, examining the changes in white matter tracts.

14
Q

How does Functional Magnetic Resonance Imaging work?

A

It focuses on the property differences between oxygenated and deoxygenated blood - neuronal activity changes are accompanied by changes in blood flow and oxygen.

15
Q

What are the pros and cons of fMRI?

A

+ Provides good spatial resolution (NB for surgery)
+ Non-invasive
+ Measures activity within seconds
+ No long lasting side effects, can be performed on the same person many times
+ Widely available
- Cannot be used with people with metal
- There’s no absolution in the nature of blood flow, it’s results are limited
- It doesn’t provide precise info on location of substances

16
Q

How does Single Cell research work?

A

An electrode is placed into the brain region of interest, then the electrical output of the cells is measured. This establishes the baseline speed of the cell, and we can discover what stimuli cause it to fire at a different rate.

17
Q

Pros and cons of Single Cell

A

+ Provides info on stimulus type for a cell’s response

- Unethical for humans, for most cases.

18
Q

Explain Electroencephalography

A

Electric signals are recorded by metal electrodes positioned on the scalp

19
Q

What is associated with the electric activity of the brain? (3)

A
  1. Different states of consciousness (frequency of alpha, beta, gamma waves)
  2. Epilepsy (neurons fire in large quantities)
  3. Experimental questions (e.g. is alpha suppression present in depression?)
20
Q

Pros and cons of EEG

A

+ Provides general info on the person’s state
+ Non invasive
+ Excellent temporal solution
- Difficult to detect the source of activity
- Difficult to detect activity of the cells orientation parallel to the brain’s surface

21
Q

Event Related Recordings method

A

Dipoles are recorded in the form of wave length and currents with positive and negative ends. It gives info about the time course with which info is processed by the brain.

22
Q

Two components in ERPs

A
  1. Exogenous - linked to the physical characteristics of a stimulus; occur early in the wave form
  2. Endogenous- driven by internal cognitive states that are independent of stimulus characteristics
23
Q

Pros and cons of ERP

A

+ Provides info on specific psychological processes, like memory and attention
+ Non invasive
+ Excellent temporal resolution
- Difficult to determine the source of the activity

24
Q

How does Magnetoencephalography work?

A

Magnetic potential produced by brain activity is recorded

25
Q

What is MEG used for? (3)

A
  1. Locating the source of epileptic activity
  2. Location primary cortices so they can be avoided in surgery
  3. Understanding cognitive processes in neurologically intact individuals and those with schizophrenia
26
Q

Pros and cons of MEG

A

+ Provides better info about the source of the activity
+ Not as susceptible to differences in conduction of tissue intervening between brain and skull
- Elaborative set up
- Cannot detect cells radial to the brain’s surface

27
Q

How does Optical Imaging work?

A

A laser source of near infrared light is positioned on the scalp and optic fibre bundles are placed a few centimeters from the light source. It’s used to measure time course and the source of neural activity

28
Q

Fast vs Slow Optical Imaging

A

Fast: Optic fibre detects how the path is altered through scattering, the changes are associated with neuronal firing
Slow: Optic fibre detect how the path is altered by absorption, looking at oxygenation and deoxygenation of the blood

29
Q

Pros and cons of Fast Optical Imaging

A

+ Non invasive
+ Inexpensive
+ Portable
+ Detects a neuronal response, not a blood based one
- Cannot provide structural info on subcortical regions

30
Q

Pros and cons of Slow Optical Imaging

A

+ Non invasive
+ Inexpensive
+ Portable
+ Allows for separate calculations for concentration of oxygenated and deoxygenated blood
- Cannot provide structural info on subcortical regions
- Works with blood, not neuronal response

31
Q

How does Transcranial Magnetic Stimulation work?

A

A pulsed magnetic field is created over the scalp, which indues an electric field - this alters the pattern of activity in the brain, in the underlying tissue. It can induce and disrupt brain activity.

32
Q

Pros and cons of TMS

A

+ Confirms lesion findings
+ Used in therapeutic treatment for clinical syndromes
+ Gives info on brain reorganization and functional connectivity
+ Determines cause of deficit: Dysfunction vs disconnection
- Small, but possible adverse effects on brain functioning
- Only works on regions close to the surface
- Doesn’t allow for precise localization of effects

33
Q

Techniques for analyzing brain behavior (4)

A
  1. Neuropsychological assessment - looks at the degree to which damage to the CNS may have compromised cognitive functioning
  2. Neuropsychological test battery - a compilation of tests ranging from sensory ability to reason and memory
  3. Estimate of premorbid functioning - a reasonable guess as to how well an individual was performing before the injury
  4. Customized neuropsychological assessment
34
Q

Techniques for assessing brain behaviour relations

A
  1. Neural networks - Created to test theories of neuropsychological functioning and derive general principles regarding brain-behaviour relationships
  2. Computational methods - Simulate mental functioning in humans after brain damage, on a computer. This allows for manipulation that isn’t possible in humans.