ways of studying the brain: fMRI Flashcards
what does studying the brain allow us to do?
Studying the brain allows psychologists to gain important insights into the underlying foundations of our behaviour and mental processes.
what is an fMRI?
Functional magnetic resonance imaging (MRI) is a brain-scanning technique that measures blood flow in the brain when a person performs a task. MRI works on the premise that neurons in the brain which are the most active (during a task), use the most energy. An MRI creates a dynamic (moving) 3D map of the brain, highlighting which areas are involved in different neural activities.
what is the difference between oxygenated haemoglobin and non-oxygenated haemoglobin?
Deoxygenated haemoglobin has a different magnetic quality from oxygenated haemoglobin.
how does an fMRI use the different magnetic qualities to detect neural activity in the brain?
An fMRI can detect these different magnetic qualities and can be used to create a dynamic (moving) 3D map of the brain, highlighting which areas are involved in different neural activities.
how long does an fMRI take to show an image of something after it occurs?
1-4 seconds
how accurate is an fMRI?
the images are thought to be accurate within 1-2 mm.
how do we know when there is more activity within an area of the brain?
An increase in blood flow is a response to the need for more oxygen in that area of the brain when it becomes active, suggesting an increase in neural activity.
AO3: how is ‘its non-invasive’ a strength to fMRIs as a way of investigating the brain?
one advantage of fMRIs as a way of investigating the brain is that is non-invasive. For example fMRIs do not use radiation or involve inserting instruments directly into the brain, and is therefore virtually risk free compared to other scanning techniques such as Positron Emission Tomography (PET) scans. This means that more participants/patients are able to undertake fMRI scans which could help psychologists to gather further data on the functioning human brain. Therefore, this helps us to understand thr functions of the human brain and consequently develop our understanding of localisation of function.
AO3: how is ‘it has good spatial resolution’ a strength to fMRIs as a way of investigating the brain?
one strength to fMRIs as a way of investigating the brain is that it has good spatial resolution. This refers to the smallest feature that a scanner can detect and is a very important feature of brain scanning techniques. This means that having greater spatial resolution allows psychologists to discriminate between brain regions with greater accuracy. For example, fMRI scans have a spatial resolution of approximately 1-2 mm which is significantly greater than other techniques such as EEGs and ERPs. Therefore, fMRIs allow psychologists to determine the activity of different brain regions with greater accuracy when using fMRI compared to EEGs and ERPs.
AO3: how is ‘poor temporal resolution’ a limitation to fMRIs as a way of investigating the brain?
one limitation to fMRIs as a way of investigating the brain is that they have poor temporal resolution. This refers to the accuracy of the scanner in relation to time or how quickly the scanner can detect changes in brain activity. We can see fMRIs have a temporal resolution of 1-4 seconds which compared to other techniques such as EEGs and ERPs which have a temporal resolution of 1-10 milliseconds. Therefore, psychologists are unable to predict with a high degree of accuracy the onset of brain activity.
AO3: how is ‘causation’ a limitation to fMRIs as a way of investigating the brain?
one limitation to fMRIs as a way of investigating the brain is that the scans don’t provide a direct measure of neural activity. This is because fMRI scans only measure changes in blood flow which means it is impossible to infer causation. Other psychologists have also argued that fMRI scans can only show localisation of function within a particular area of the brain but are limited when showing the communication that takes place among the different areas of the brain which may be critical to neural functioning. Therefore, this means that although blood flow is able to indicate activity within a certain area of the brain, it is unable to conclude if this particular brain region is associated with a particular function.
