Research Methods in Biopsychology Flashcards
How do C(A)T scans work?
They create 2d slice through a 3d object, creating a tomogram
It is a computer assisted X ray procedure in which an x ray scanner is rotated 180 degrees around the body, one degree at a time, therefore making it a non-invasive procedure
How does MRI scanning work?
A strong magnetic field causes the protons in tissue to align in a specific orientation to fit with the magnetic field
When a radio frequency is passed through this, the protons are thrown out of equilibrium and strain against the magnetic field
When the radiofrequency is turned off, the MRI protons will move back to the original orientation, and will release electromagnetic energy whilst they do this
When the radiofrequency is turned off, the MRI sensors are able to detect the energy released, and detect what type of tissue it is as different tissues release different signals
What are three advantages of MRI scans over CT scans?
CT scans expose people to ionising radiation (health risks)
They have better resolution
They can create a 3d image that you can dissect yourself into coronal, sagittal or horizontal planes
How do fMRIs work?
The brain does not store glucose, so the blood will change in flow to supply what areas need glucose the most.
Oxyhaemoglobin can not be magnetised (it has a different magnetic field to deoxyhaemoglobin)
Therefore, when can tell through the magnetisation and tracking proton movement when an area has a lot of deoxyhaemoglobin, so is therefore being stimulated
What is a BOLD signal?
Blood-Oxygen- level- dependent signal
What are two drawbacks of EEGs and two positives?
Drawbacks:
- poor spatial localisation as the recordings are made from the scalp
- better suited to answering questions of “when” in the brain rather than “where” in the brain
Positives:
- high temporal resolution
- less expensive than fMRI
How does intracellular recording work?
We put an electrode into the cell and record the changes in membrane potential
How does extracellular recording work?
An electrode sits on the outside of the cell and records the change in potential around the membrane
What are the two most common stimulation techniques?
electrical, using electrodes
Optogenetics- stimulating parts of the brain using light
What are three neuropharmacological techniques?
microdialysis- a semi permeable probe is inserted into a specific brain site. Fluid is perfused through the probe and chemicals in the fluid across the membrane is collected. Samples are then analysed for chromatography methods, to help us monitor the presence/levels of neurotransmitters
What is immunohistochemistry?
We can localise neurotransmitters in different cells by dying specific neurons, with a process of two antibodies (the second antibody binds to a reporter molecule that creates either fluorescence or a black colour)
What is one example of disruptive techniques of studying the brain?
chemical lesions- we stop parts of the brain from producing certain neurotransmitters
What are the behaviours we often focus on in animal behaviour paradigms?
species common behaviours
Describe the morris water maze?
It observes spatial memory
Tank filled with a liquid with a submerged platform that the animal must find by swimming around. The tank also has markers like curtains. The rat is taken out and put back in the water and we then measure how long it takes to find the platform in the water. The rat is put in different start locations (N,S,E and W). Eventually, regardless of location, the rat learns to swim directly to the platform
The main measures in this is: escape latency- how long the rat takes to escape and spatial transfer test.
What is the radial maze and what are the two ways it can test memory?
The rat tries to find food in a circular maze.
When the rat goes back to arms of the maze that they have already been to, this indicates weakness in working memory. You can also pick a specific arm to add more and more food to and then track their errors in the maze, now relating to reference/long term memory
What are field observations?
They can help study evolution/gene-behaviour relationship
We can study things like polygymy, aggression, how submission can reduce sexual prowess, sexual behaviours etc.
What is the difference between usual x rays and cerebral angiography?
Usual x rays can only see things that have significantly different states to the tissue around it (i.e. bone) as it absorbs such a different amount of radiation. in CA, a substance that absorbs less or more radiation than the surrounding tissue is injected into a cerebral artery, so it allows to see the cerebral circulatory system
What does CT scan stand for?
Computed Tomography scan
What does PET scan stand for?
Positron Emission Tomography
Explain a common version of PET scans involving Fluorodeoxoglucose
FDG is injected into a cartoid artery. It is radioactive. Because it has a similar structure to glucose, it is absorbed into the cells that require fuel. It can then detect what brain areas are being activated, as they are the ones that need more fuel, so will have different levels of FDG and radiation picked up by the scan
Why can PET scans be construed as slightly inaccurate?
It is just a lot of colours indicating the different levels of radioactivity in the brain. It is therefore often very pixelated and has low resolution, as they are not real images.
Do PET scans detect brain activity or structure?
activity
