Brain Scans Flashcards
1
Q
What is Post- mortem?
A
The examination of the brain after a person has died.
2
Q
What are examples of Post- mortem?
A
- Brocca (1861)
- Charles Whitman (1966)
- Phineas Gage (1860)
3
Q
What’s an EEG’s [Electroencephalogram]?
A
- Small sensors/ electrodes are attached to the scalp. They pick up electrical signals produced when brain cells send messages to each other.
- The machine is only recording the activity of your brain. It does not stimulate it.
A neurologist will monitor for any unusual readings in your brain wave patterns.
4
Q
Dement and Kleitman (1957)?
A
- Used EEG’s to explore different stages of sleep.
- As people sleep their brain waves slow down.
- During Rapid Eye movement [REM] sleep brain waves increase.
- Found that REM sleep correlated with dream recall compared to other stages of sleep.
5
Q
What is a CAT Scans [Computed axial tomography]?
A
- Rotating x- ray machine to create 3D images.
- Lasts 10-20 minutes.
- Non invasive but does use targeted radiation
- Can diagnose Cancer, tumour and structural damage as can detect normal and abnormal organs.
- Shoots narrow beams of X-rays through the body.
- The computer generates a 3D image from several 2D images of a slice of body. Typically 1 to 10mm thick.
6
Q
Johnstone et al (1979)?
A
Used CAT Scans to compare the brains of those with schizophrenia and people without schizophrenia.
Results:
Schizophrenia brains were different to normal brains as the ventricles [fluid filled spaces] were much larger.
7
Q
What is an MRI scans [Magnetic resonance imaging]?
A
- This type of scan uses strong magnetic fields and radio waves to produce detailed images of the inside of the body.
- Lasts longest amount 15- 90 minutes
- Non Invasive and no potential risks such as radiation
8
Q
How do MRI scans work?
A
- The human body is made up of water molecules. [Hydrogen and oxygen atoms]
- The atoms act like tiny magnets and sensitive to the magnetic field produced by the MRI scan.
- Short bursts of radio waves are sent to certain areas of the body knocking the atoms out of alignment.
- When the radio is turned off the protons realign and produce an electromagnetic signal that is translated by the computer into pictures.
9
Q
What is a PET Scans [Positron emission tomography]?
A
- Radioactive glucose (FDG) is injected into the patient.
- The brain uses glucose for energy, the more active parts using more glucose.
- This will leave a faint radioactive trace in the parts of the brain that have been most active.
- This can then be detected by a PET scan
- Duration 30 minutes
- Non-invasive treatment however patient is injected with a small amount of radioactive substance so can only be used a few times.
10
Q
Example of PET scans?
A
Rainer et al (1997):
- Used PET scans to compare brain activity in murderers and normal individuals.
- They found differences in areas of the brain such as the prefrontal cortex and the amygdala.
- Regions previously associated with aggressive behaviour.
11
Q
Strengths of EEG’s?
A
- Non invasive and readily available
- Low cost and low risk
- Good for monitoring epilepsy and identifying type of seizure.
- Can record brain activity immediately.
- Can have family members in the room with you
12
Q
Weaknesses of EEG’s?
A
- Can’t locate damaged area of the brain as electrical activity can be detected in several areas.
- Can’t discriminate between different brain areas.
- Is uncomfortable as electrodes are glued to the scalp
13
Q
Strengths of CAT scans?
A
- Most detailed in producing high quality images. [Images in 3D]
- Shows a range of different tissue types so can diagnose cancer and tumours for example.
- Faster and less sensitive so good choice for a trauma
14
Q
Weaknesses of CAT scans?
A
- Uses ionising radiation so limit to number of scans you can use.
- CAT scans can only provide structural information.
- Fewer CAT scans available then other hospital equipment such as X-rays
- Not as detailed as MRI scans
15
Q
Strengths of MRI scans?
A
- Safer than other types of scans as uses a magnetic field through the patient.
- Patients can use the machine repeatedly.
- MRI scans give more detailed images of soft tissue in the brain.
- Better for showing changes in the brain over time such as dementia.
