Bio Psych 3: Ways of measuring the brain

Question 1

What is an ablation?

Answer 1

An ablation is the removal of a brain area, generally with a surgical knife

Question 2

What does lesion mean?

Answer 2

damage

Question 3

What is a TMS?

Answer 3

transcranial magnetic stimulation (TMS), the application of magnetic stimulation to a portion of the scalp, stimulates neurons below the magnet if the stimulation is brief and mild, but with stronger stimulation, it inactivates the neurons, producing a “virtual lesion” that outlasts the magnetic stimulation itself

Question 4

Why do researchers use a TMS?

Answer 4

It enables researchers to study behaviour

Question 5

If brain damage impairs a behaviour, what should stimulation do?

Answer 5

If brain damage impairs a behaviour, stimulation should increase it

Question 6

What is an EEG?

Answer 6

An electroencephalograph (EEG) records the electrical activity of the brain through electrodes glued to the scalp that measure the average activity at any moment for the population of cells under the electrode

Question 7

What is an EEG useful for?

Answer 7

An EEG is useful for distinguishing between wakefulness and various stages of sleep. It can also help with the diagnosis of epilepsy

Question 8

What are evoked potentials or evoked responses?

Answer 8

brain activity in response to a stimulus

Question 9

What is an MEG?

Answer 9

it measures the faint magnetic responses generated by brain activity

Question 10

What is good about MEGs?

Answer 10

An MEG has excellent temporal resolution, able to record changes from one millisecond to the next

Question 11

What does PET do?

Answer 11

Positron-emission tomography (PET) provides a high-resolution image of activity in a living brain

Question 12

How does a PET work?

Answer 12

person receives an injection of glucose labeled with radioactive atoms. Because the most active brain areas increase their intake of glucose, tracking the glucose identifies areas of increased activity

Question 13

What is a con of PET?

Answer 13

The machines are only available at research hospitals

Question 14

What is another con of PET?

Answer 14

They expose an individual to radioactivity

Question 15

What has the exposing of individuals to radioactivity led to researchers using instead of PET?

Answer 15

An fMRI, which is also less expensive and risky

Question 16

What does fMRI stand for?

Answer 16

functional magnetic resonance imaging

Question 17

What is an fMRI

Answer 17

A brain imaging technique that measures brain activity by detecting changes in blood flow. When a specific area of the brain is more active, it requires more oxygen, leading to increased blood flow to that region

Question 18

What is a pro of EEG and MEGs?

Answer 18

They both provide precise information about the timing of activity

Question 19

What are the cons of EEG and MEGs

Answer 19

They only offer approximate information about location, and they are sensitive only to cells near the surface of the brain, EEG data is noisy so lots of trials are needed, EEG has poor spatial resolution

Question 20

What are pros of PET and fMRIs?

Answer 20

They provide detailed information about the location

Question 21

What are cons of PET and fMRIs?

Answer 21

They’re only able to give approximations about the timing of activities and require a lot of time and effort

Question 22

What are the cons of fMRI?

Answer 22

Interpreting the meaning of data can be difficult. In most cases, the results aren’t reliable enough to draw conclusions about an individual

Question 23

What is used sometimes to treat epilepsy and how?

Answer 23

A Corpus Colostomy. Dividing the corpus callosum limits electrical activity flowing from one side to another

Question 24

What is a way of examining detailed brain anatomy in people?

Answer 24

CAT scans

Question 25

What happens during a CAT or CT scan

Answer 25

injects a dye into the blood to increase contrast in the image and then places the person’s head into a scanner. X-rays pass through the head to be recorded by detectors on the opposite side. The scanner rotates slowly to take a measurement at each angle. From the measurements, a computer constructs images of the brain

Question 26

What is a pro of an MRI?

Answer 26

MRI can depict anatomical details smaller than a millimetre in diameter

Question 27

What is a con of an MRI?

Answer 27

The person must lie motionless in a confining, noisy apparatus

Question 28

Advantages of using a TMS?

Answer 28

Can study functional integration, can be used to determine timing of cognition

Question 29

Advantages of organic lesions?

Answer 29

Subcortical lesions can be studied, lesions can be accurately localised with MRI, and changes in behaviour/cognition are more apparent

Question 30

What are single-cell recordings?

Answer 30

Measurement of the responsiveness of neurons via action potentials. It is invasive

Question 31

How are single-cell recordings done?

Answer 31

Using microelectrodes which impale the cells of interest

Question 32

What is focal epilepsy?

Answer 32

Large electrical discharge in the focal area then spreads throughout the brain

Question 33

What is general epilepsy?

Answer 33

Affects both hemispheres of the brain simultaneously

Question 34

Other cons of MEGs?

Answer 34

Expensive and limited availability, poor at detecting deep dipoles

Question 35

What are the pros of EEGs?

Answer 35

Detects deep and shallow dipoles, cheaper and widely available

Question 36

What are the methods to look at structural imaging?

Answer 36

CT and MRI

Question 37

What are methods to look at functional imaging?

Answer 37

PET and fMRI

Question 38

What does an MRI create an image of?

Answer 38

Soft tissue

Question 39

What are the advantages of using an MRI over a CT?

Answer 39

No use of ionising radiation, differentiates between grey and white matter, better spatial resolution, same machine for fMRI

Question 40

What are the advantages of using a CT over an MRI?

Answer 40

Less expensive, more readily available, CT is fast so ideal in emergencies