Research Methods Flashcards
What are the 5 techniques used to measure brain activity?
Structural, Functional, Non Imaging, Animal, and Neuropsychological Techniques
What is Structural Imaging Techniques?
What the brain looks like
What are the components to Structural Imaging Techniques?
X - ray: which are 2D image on film and best for hard tissues such as bones ~ doesn’t pick up tissues or muscles
Computerized Tomography (CT) scan - CAT Scan: series of X-ray style images taken by a specialized computer and better at soft tissues than X- ray
Magnetic Resonance Imaging (MRI): uses powerful magnets to get an image of the brain, no radiation, and can see tissue & everything in better details
What are the 2 main techniques in Functional Imaging?
Direct and Indirect Techniques
What are the sub techniques in direct imaging?
Electroencephalography (EEG) and Magnetoencephalography (MEG)
What are the sub techniques in indirect imaging?
Positron Emission Tomography (PET) and Functional Magnetic Resonance Imaging (FMRI)
What is an EEG?
it records electrical activity from electrodes that are on the scalp and electrical activity smears through the skull
What is spatial resolution?
how accurately can researchers figure out where the activity occurred
what is temporal resolution?
how accurately can researchers figure out when the activity occurred
What are EEG’s spatial and temporal resolution?
EEG has poor spatial resolution (lobes) - not precise and good temporal resolution (ms-difference in miliseconds)
What are the pros and cons for EEG?
Pros:
-good temporal resolution
-relatively cheap
-able to conduct it in a small space
Cons:
-poor spatial resolution
-activity closest to the scalp is easiest to measure
What is a MEG?
-every electrical field has a perpendicular magnetic field
-MEG detects the magnetic field (EEG would detect the electrical field)
-magnetic fields don’t smear through the skull
What are the pros and cons for MEG?
Pros:
-good temporal resolution (ms)
-better spatial resolution than EEG
Cons:
-spatial resolution still not great
-only measures information in the grooves/sulci of the brain
-very expensive and not commonly found
What is direct imaging and which techniques are used
Direct imaging techniques directly measure electrical (or magnetic) activity from the brain.
- Typically use EEG and MEG
What is indirect imaging and which techniques are used?
Indirect Imaging techniques measure something else and assume it relates to electrical activity from the brain - Typically use PET and FMRI and measures blood flow
What does a PET scan do?
a tracer is injected into the bloodstream, positrons are emitted from the tracer and creates a map of where the activity came from over a span of multiple minutes
What are the pros and cons of PET scans?
Pros:
spatial resolution is good (cm)
Cons:
-temporal resolution is poor (minutes)
-small levels of radiation exposure in PET scans
What does a FMRI do?
It is able to detect changes in the blood flow by looking at oxygen levels and can easily take a structural MRI scan while the subject is in the scanner
What are the pros and cons of FMRI?
Pros:
-spatial resolution is good (mm)
-temporal resolution is better than PET, but not as goof as EEG/MEG
-no radiation (unlike PET)
Cons:
-scanner is loud
-only so many things you can do inside of a magnet
What is an another concern about PET and FMRI?
- both are indirect techniques
-the assumption that blood flow equals brain activity is incorrect, the findings of PET and FMRI would be incorrect
What non imaging technique is used ?
Transcranial Magnetic Stimulation (TMS)
What does TMS do?
uses magnetic wand to stimulate/inhibit the brain, magnetic waves travel through the skull easily, and can excite a brain area or inhibit it
What are the applications used for TMS?
-it is used clinically for many disorders including: schizophrenia, depression, Alzheimers, and autism spectrum disorder
- rTMS can reduce brain activity and possibly stimulate cortical plasticity
What animal technique(s) are used?
single - cell recordings
What does single - cell recordings do?
- an invasive technique
- records activity using a tiny device known as a mircoelectrode
-allows researchers to determine the specific function of a neuron
What are the pros and cons of single-cell recordings?
Pros:
-excellent temporal and spatial resolution
Cons:
-misses what is happening everywhere else in the brain
- damaging to the brain of the subject
- recordings are likely extracellular and gathers activity from a few cells
What are the 3 neuropsychological techinques?
direct cortical stimulation, Wada procedure, and surgeries
What is direct cortial stimulation?
researchers apply a small electrical current directly to the brain and can excite or inhibit areas - typically done as a part of cortical mapping ~ allows doctors to map put areas of the brain in order to help them navigate the brain during surgery
-implanted grids of electrodes that allow for stimulation between surgeries
What is Wada procedure?
-inject a barbiturate to put one half of the brain to sleep
-researchers are able to determine the functions of each brain hemisphere
What do surgeries do?
- removal of parts of the brain have been useful to understand what those areas were responsible for
- the smaller the part removed, the easier it is to determine what it did
What is an example of surgeries for neuropsychological techniques?
split brain studies
what are split brain surgeries?
series of surgeries that cut the corpus callosum in a handful of epileptic patients
-left side: processed in the right hemisphere, the left hand can draw it, and can’t speak
-ride side: processed in the left hemisphere and can speak it
What is a concern about neuropsychological techniques?
- subjects brain aren’t “normal” to begin with
- not clear how generalizable these findings are
What is animal subject research?
-nervous systems are less complex
-have shorter life cycles
-have larger neurons
-have translucent embryos
- has to be approved by the Institutional Animal Care and Use Committee at the institution
What are the three R’s for animal subject research?
the three R’s:
- Replacement ~ try to use inanimate systems instead of animal subjects
-Reduction ~ use fewer animals if possible
-Refinement ~ minimize discomfort for the animal subjects
