MRI
Why can you not wear metal in an MRI?
Because it's a giant magnet.
What does an fMRI measure?
The blood flow between neurons (or, the different areas of the brain that are activated during a particular task)
MRIs use magnetic fields and (....) waves.
Radio
What were two research methods that were commonly used to study the brain before the invention of fMRIs and MRIs?
Case studies and animal experimentation (invasive techniques)
What brain imaging machine did Draganski et al use in their experiment into structural brain changes in the brain in response to learning to juggle?
MRI
What do the scanned images from an MRI machine show?
The structure (i.e. size and shape) of a brain.
What is the major correlation that can be determined by the use of the fMRI machine?
The correlation (relationship) between a particular cognitive process or behaviour and an area of the brain that is associated with that process or behaviour.
What is the name of one other brain imaging technology commonly used?
PET (Positron Emission Tomography);
CAT/CT (Computerized axial tomography)
What is one limitation of using animal experimentation to study the brain?
It's difficult to generalize to humans; there are numerous ethical considerations to be factored into the research
Why did researchers perform an MRI scan on HM?
To see exactly what areas of his brain had been removed.
Name one study which uses MRI and explain the aim.
Maguire et al (2000)
To compare brain structure in people with extensive navigational skills (London taxi drivers) and controls.
Draganski et al (2004)
To investigate changes in grey matter volume as a result of practising a simple juggling routine.
What does BOLD stand for?
blood-oxygen-level dependent (signal)
Why are MRIs and fMRIs known as "non-invasive techniques"?
Because they don't require the brain to be cut open in order to study it.
What are two limitations of using case studies to study the brain?
Difficult to generalize as small sample size; can be time consuming; there are numerous ethical considerations; check your notes for other answers
Give two examples of studies that used MRI.
MRI: Maguire et al (2000); Draganski et al (2004).
What does MRI stand for?
Magnetic Resonance Imaging
What does it mean to say that the fMRI provides "more dynamic rather than static" information?
An fMRI can measure neurotransmission occuring in the brain as it happens, instead of only providing "snap-shot" type information like in an MRI. It is showing on-going activity, i.e. activity over a period of time.
What is the major difference between the MRI and fMRI machine?
MRI shows the STRUCTURE, fMRI records ACTIVITY / PROCESS.
What did Lashley do to the brains of rats to investigate the localisation of memory in the brain?
Ablation (removal of more and more brain mass).
If Merzenich conducted his experiment now, what technology could he use to investigate neuroplasticity in owl monkeys in response to injury more ethically?
MRI - it could show the differences in the structures of the brain or fMRI which would show differences in brain activation.
What are three limitations of the MRI?
- Can be expensive.
- Can be difficult for children.
- Can cause claustrophobia.
- People with metal in their bodies cannot use it.
- Only shows structure, not processes.
What does fMRI stand for?
Functional Magnetic Resonance Imaging
What is one strength and one limitation of fMRI?
Strength: Don’t involve harming the participant in any way; a big limitation of PET and SPECT is the need to inject a radioactive substance and animal studies of course involve harming the animals irreversibly. Shows ongoing brain processes and produces excellent spatial resolution.
Limitation: fMRI studies may suffer from a lack of generalizability due to the artificiality of the environment and/or procedures used. Eliminating noise (from head movements, fidgeting, random thoughts, and random noise) requires a lengthy experimental procedure with many trials. Temporal resolution of around 1 second means only relatively long-lasting processes can be studied.
What does lesion and ablation stand for?
Lesion = damage
Ablation = removal
The results of Maguire's study showed that taxi drivers had ________ grey matter volume in the ___________ compared to the control group subjects. On the other hand, control subjects had __________ grey matter volume in the _________________.
This means that redistribution of grey matter occurred in the ___________ of taxi drivers, from the _________ to the _______.
The results of Maguire's study showed that taxi drivers had INCREASED grey matter volume in the POSTERIOR HIPPOCAMPUS compared to the control group subjects. On the other hand, control subjects had INCREASED grey matter volume in the ANTERIOR HIPPOCAMPUS.
This means that redistribution of grey matter occurred in the HIPPOCAMPUS of taxi drivers, from the ANTERIOR to the POSTERIOR. All of which supports the idea of neuroplasticity in humans in response to learning.