Chapter 5 - Week 2

Question 1

What are contrast X-rays useful for?

Answer 1

For visualising the brain, as oppose to the conventional x-ray.

Question 2

How does a contrast x-ray work?

Answer 2

Injecting something in the body which absorbs x-rays either less or more than the surrounding tissue.

Question 3

What is cerebral angiography?

Answer 3

The infusion of radio-opaque dye into a cerebral artery to visualise the cerebral circulatory system during an x-ray photo.

Question 4

What is a cerebral angiography good at localising?

Answer 4

Vascular damage.But can also indicate the location of a tumour.

Question 5

What is computed tomography?

Answer 5

a computed assisted x-ray procedure that can be used to visualise the brain and other internal structures of the living body.

Question 6

What is the process of using computed tomography?

Answer 6

The patient lies with their head positioned in the centre of a large cylinder. On one side is the x-ray and on the other is an x-ray detector, which identifies the beam being shone by the x-ray.

Question 7

In computed tomography, why does the x-ray move around the head?

Answer 7

To take multiple photos and get multiple angles to provide a 3 dimensional image of the brain.

Question 8

What does a positron emission tomography measure?

Answer 8

Brain activity; it is functional not structural.

Question 9

Commonly, what is injected into the brain during a positron emission tomography?

Answer 9

Flurodeoxyglucose is injected into the patient’s carotid artery. This produces a “coloured map” of where the most brain activity is.

Question 10

What is magnetic resonance imaging?

Answer 10

A magnetic field based technique for imaging the human brains 3 dimensional, spatial structure.

Question 11

How does magnetic resonance imaging (MRI) actually work?

Answer 11

Is measured the radio-frequency waves that hydrogen atoms emit as they align with a powerful magnetic field, providing clearer images than a CT scan.

Question 12

Which MRI technique has even been used to communicate with patients in. a vegetative state?

Answer 12

Functional MRI.

Question 13

What is measured during an fMRI, and how does is this possible?

Answer 13

Measures the function of a brain by producing images which show the increase in oxygen flow in the blood to active areas in the brain.

Question 14

fMRIs produce functional images by using oxygenated blood. How is this blood demonstrating anything useful? 2 reasons

Answer 14

(1) Because active areas of the brain take up more oxygenated blood than they need for their energy requirements, and thus this is where it accumulates. (2) Also, oxygenated blood has magnetic properties that influence the radio-frequency waves emitted by hydrogen atoms in an MRI.

Question 15

What are four advantages the an fMRI has over a PET scan?

Answer 15

1. nothing needs to be injected
2. provides both structural and functional information
3. its spatial resolution is better
4. can produce 3D images

Question 16

What is the “magnetic” technique, diffusion tensor imaging and how does it work?

Answer 16

A method of identifying pathways in the brain that water molecules rapidly diffuse. Shows major tracts.

Question 17

What is one shortcoming about PET and fMRI scans in measuring brain activity?

Answer 17

It can be used to see a correlation between brain activity and cognitive activity but cannot actually say that the brain activity caused the cognitive activity.

Question 18

What is transcranial magnetic stimulation?

Answer 18

It can be used to establish the causal affects of human cortical activity on cognition and behaviour.

Question 19

How does transcranial magnetic stimulation work?

Answer 19

It is used to turn off an area of the human cortex by creating a magnetic field under a coil positioned next to the skull. It can also be used to “turn on” parts of the brain.

Question 20

What is transcranial direct current stimulation (tDCS) and how does it work?

Answer 20

Stimulates (“turns on”) an area of the cortex by applying an electrical current through two electrodes placed directly on the scalp, which temporarily increases brain activity.

Question 21

What is scalp eletroencephalography?

Answer 21

The electroencephalogram (EEG) is a psychophysiological measure of gross electrical activity recorded through large electrodes which are attatched to the scalp.

Question 22

What is magnetoencephalography?

Answer 22

Another technique used to monitor brain activity from the scalp of human subjects. It measures the changes in magnetic fields that are produced by underlying patterns of neural activity.

Question 23

What does electromyography measure?

Answer 23

Muscle tension.

Question 24

What is stereotaxic surgery?

Answer 24

An invasive, stereotaxic instrument is inserted and an electrode holder is moved in three dimensions.

Question 25

What is one problem with lesions that people often forget?

Answer 25

Because most experimentation is performed on small, rat brains, it is almost impossible to severe something without also causing surrounding damage.

Question 26

Invasive, electrical stimulation, is often seen as a very important psychological research tool; why?

Answer 26

Because it can illicit behavioural responses including eating, drinking, attacking etc.

Question 27

What are two techniques used in genetic engineering?

Answer 27

Gene knockout and gene replacement.

Question 28

Where is the term brainbow used?

Answer 28

It is used to colour certain types of neurons. So when each of them have a different colour to be measured, it produces a colourful image.

Question 29

In most people, which hemisphere is most dominant for language?

Answer 29

The left hemisphere.

Question 30

What is the basic aspect of pavlovian conditioning?

Answer 30

The experimenter pairs an initially neutral stimulus called a conditional stimulus with an unconditional stimulus (meat powder) which elicits an unconditional response (salivating).