Neuroimaging Flashcards
(16 cards)
What is the main goal of measuring brain activity?
To measure brain activity related to behaviour or processes, non-invasively and in-vivo.
What does an EEG measure?
Differences in electrical activity across the skull to infer underlying cortical structures.
How is EEG data collected?
Using electrodes embedded in a net or cap, usually with gel or solution for better connection to improve the connection between the electrodes and the head.
What are the components of EEG signals?
Measure signal + noise
Signal: electrical activity related to cognition/ process
Noise: anything thats not in the brain
What are artifacts in EEG?
Signals that are not related to brain activity, such as muscle activity.
What are the strengths and weaknesses of EEG?
Strength: Great temporal resolution: when processes occur.
Weakness: Bad spatial resolution: where processes occur in the brain
What are some applications of EEG?
Investigating cognitive processes, studying epilepsy, researching sleep stages, and identifying markers of psychiatric disorders.
What does MRI generate, and what is this useful for?
An image of the structure of the brain, which can show abnormalities in the brain and body
How does an MRI work?
It is a very big magnet, with a typical strength of 1.5-3T.
When the strong magnetic field is applied, it aligns the orientation of protons, but they are still spinning
An external radio frequency pulse (energy) un-aligns the protons from the magnetic field
As protons re-align, they release energy that is recorded by the scanner
What are we measuring in MRI?
The alignment and energy release of protons in the tissue when subjected to a magnetic field.
How do different tissues appear in MRI?
Different concentrations of hydrogen protons result in varying appearances on the scan.
What does fMRI measure?
It represents behaviour as areas of the brain that are active.
What is the BOLD signal in fMRI?
Blood Oxygen Level Dependent signal, indicating changes in blood flow related to neuronal activity.
What are the strengths/ weaknesses of MRI/fMRI?
Strengths: High spatial resolution for structural and activity differences
Weaknesses: Expensive, bad temporal resolution which makes it hard to link structure and behaviour in real time
What are some applications of fMRI in research?
Studying activity related to behaviour, co-activation of brain areas, and network analysis.
How does an fMRI work?
Higher neuronal activity means higher need for oxygen, which means the blood has more oxygen heamoglobin.
