Questions and Answers 100% Pass
Electroencephalography: Invasive or non invasive? - ✔✔- non-invasive measure of
brain activity
- Completely safe and painless procedure
Electroencephalography:
Measures (3)? - ✔✔1) electrical activity of brain provides a unique insight how the brain
reacts to external stimuli
2) Reveals changes in brain state associated with differing levels of arousal or under
different experimental conditions
3) Reveals chronology of mental processes.
- Eg: Auditory stimuli, memory, target detection (when you miss it when you dont)
Electroencephalography: Resolution (2)? - ✔✔1) Excellent temporal resolution
2) Poor spatial resolution
Electroencephalography: Records? - ✔✔record potential differences (micro-volts)
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,Electroencephalography: Instruments? - ✔✔array of surface electrodes on the scalp
Electroencephalography: Usually used for? - ✔✔- Much psychological research is based
on measuring the speed and accuracy of participants' responses - (i.e. reaction time
tests).
Electroencephalography: What does it record? - ✔✔EEG can show what happens in the
brain before, during and after a response button is pressed. (reporting continously,
leading up to, during, after) (brain response then behavioural response, see what brain
does after response)
How does an Electroencephalography work? - ✔✔- The brain is always active, whether
awake or sleeping... or even while under anesthesia...
- brain cells communicate by passing electrical impulses back and forth. The purpose of
EEG is to measure the electrical activity resulting from the interactions between neurons
Electrodes:
Measures?
Instrument? - ✔✔-key to measuring these electrical charges
-flat, metal discs which are attached to the scalp and an EEG caps have multiple
electrodes
So how many electrodes should your EEG cap have?
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, also available with 32, 64, 128 electrodes for?
Systems available with 4, 10 or 24 channels (3)? - ✔✔-EEG caps with 10-20 electrodes
should be adequate for most academic needs but depends on the research your doing
- also available with 32, 64, 128 electrodes for more advanced imaging studies
- Systems available with 4, 10 or 24 channels. These include an additional ECG (heart
activity), EMG (muscle activity) or EOG (eye movement) channel.
What about electrode placement (2)? - ✔✔1) The cap must allow electrodes to be
positioned precisely... placed according to international standards.
2) Make sure to choose an EEG cap that is sized accurately. EEG headsets should come
with a variety of sizing options and be easily adjusted.
What about the amplifier? - ✔✔Signal quality is of vital importance when it comes to
EEG. The initial EEG signal is comprised of low frequency fluctuations which need to
be amplified. As a result, the amplifier is often the most expensive and defining feature
of an EEG headset. If there is one thing to check, make sure it's that the amplifier is of
the highest quality.
Should I use wet or dry electrodes? - ✔✔- "Wet electrodes" use a conductive gel to
improve signal quality while "Dry Electrodes" do not require such gel.
- The gel used can be sticky and unpleasant for participants. For this reason many of
those wishing to use EEG for market research purposes opt for dry electrodes in order
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