(EEG) (B7) Exam Questions and
Answers 100% Pass
A flat EEG (no electrical activity) is clinical evidence of - ✔✔death
Patterns of rhythmic neuronal electrical activity recorded are called - ✔✔brain waves
(brain rhythms)
scalp EEG - ✔✔a pair of electrodes are attached to scalp connected to a differential
amplifier
•Amplifier will reveal a pattern of voltage fluctuations over time
•Amplitude between -100 µV and +100 µV
•Frequency 0-100 Hz
neural basis of EEG - ✔✔- its a measure of the extracellular current flow from the
summated synchronous activity of many neurons
- The most important source of extracellular flow of ions in brain tissue is triggered by
excitatory and inhibitory postsynaptic potentials
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, - collects the activity mainly from cell layers that are oriented perpendicular to the
surface of the cortex
positive deflection EEG - ✔✔EPSPs in deeper layers and IPSPs in superficial layers
negative deflection EEG - ✔✔EPSPs in superficial layers and IPSPs in deeper layers
can scalp EEGS alone determine cortical synaptic events - ✔✔no
can APs of neurons be detected on the scalp - ✔✔no
- they are asynchronous and too fast to generate detectable potentials
what happens to electrical activity from deeper generators - ✔✔it gets dispersed and
attenuated by volume conduction effects
what activity might scalp EEG indirectly trace - ✔✔The activity from deeper structures
may drive cortical pyramidal neurons
EEG collects its activity from which cell layers - ✔✔cell layers that are oriented
perpendicular to the surface of the cortex (prymidal neurons)
what is the EEG signal distorted by - ✔✔the filtering and attenuation produced by
intervening layers of tissue and bone (act like resistors and capacitors)
electrode placement - ✔✔Location of the electrode is specified in terms of its:
- proximity to brain lobes
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