Neuroscientific imaging techniques

Question 1

CAT scan

Answer 1

Computer-assisted tomography

- tomograms are 2-dimensional horizontal brain scans

Question 2

CAT scan process

Answer 2

through a computer-assisted X-ray procedure a series of tomograms is being taken of the brain (or potentially other body parts)

Question 3

Strengths of CAT scans

Answer 3

1) can identify subcortical structures at relatively good resolution
2) commonly used and available in most hospitals
3) can show pathological brain condition (e.g. tumors, lesions, blood clots) and their location to determine whether surgery is necessary and safe
4) non-invasive with only a small brief exposure to x-ray radiation

Question 4

Weaknesses of CAT scans

Answer 4

1) can only provide tomograms

2) not useful for precise location and identification of structures

Question 5

MRI scan

Answer 5

Magnetic Resonance Imaging

Question 6

MRI process

Answer 6

a magnetic field causes radio-frequency waves that excite hydrogen atoms in the brain

Question 7

Strengths of MRI

Answer 7

1) can produce a 3-dimensional image
2) higher resolution (almost exact)
3) can detect issues and is used to study brain structures
4) completely non-invasive

Question 8

Weaknesses of MRI

Answer 8

1) the patient has to lie completely still for a long time while the scan is made
2) only a few cognitive tasks are possible to perform while one is lying in the scanner

Question 9

PET scan

Answer 9

Positron Emission Tomography

Question 10

PET scan process

Answer 10

• radioactive 2-deoxyglucos (2-DG) is injected into the carotid artery, which is then picked up by active neurons but cannot be metabolised as quickly as normal glucose
• a computer can then measure the radiation level and present a tomographic image

Question 11

Strengths of PET scans

Answer 11

1) provides additional information on brain activity rather than structures

Question 12

Weaknesses of PET scans

Answer 12

1) spatial and temporal resolution is not great
2) regions that light up are not necessarily related to the task that is being studied
3) it is difficult to find control tasks
4) method is invasive

Question 13

fMRI

Answer 13

functional MRI

Question 14

fMRI process

Answer 14

measures oxygen flow during activity

Question 15

Strengths of fMRI

Answer 15

1) non-invasive
2) provides the almost exact spatial resolution of MRI
3) produces a 3-dimensional image

Question 16

Weaknesses of fMRI

Answer 16

1) not excellent temporal resolution, no instantaneous activation can be measured

Question 17

EEG

Answer 17

Electroencephalography

Question 18

EEG process

Answer 18

measures gross electric activity

Question 19

Strengths of EEG

Answer 19

1) good temporal resolution

Question 20

Weaknesses of EEG

Answer 20

1) can only measure cortical areas close to skull

Question 21

ERP

Answer 21

Event related potentials

Question 22

ERP process

Answer 22

repeated EEGs for a specific event/repeated task that can then show average activity

Question 23

Strengths of ERP

Answer 23

1) good temporal resolution

Question 24

Weaknesses of ERP

Answer 24

1) bad spatial resoultion

2) can only measure cortical areas