Quiz 03: From brain to file: the signal path

6 questions on lesson 3. Nothing is timed. Pick one answer for each, then check them.

1. In which order does the signal pass through these steps? Cortex → skull and scalp → electrode → amplifier → filter → digitiser → file Cortex → electrode → skull and scalp → filter → amplifier → digitiser → file Electrode → cortex → amplifier → skull and scalp → filter → file → digitiser Cortex → skull and scalp → digitiser → electrode → amplifier → filter → file

2. What happens to the signal as it passes through the skull and scalp? It gets stronger Nothing changes It turns into a magnetic signal It gets much weaker and spreads over a wide patch of scalp

3. What does the differential amplifier do? Removes all brain activity below 1 Hz Subtracts the reference, so noise both electrodes share cancels, then boosts the voltage Turns the voltage into numbers Records each electrode on its own, with no reference

4. What does the digitiser do? Places the electrodes on the head Removes eye blinks Measures the voltage at a fixed rate and rounds it to steps Makes the signal smoother

5. What does the filter step do? Keeps the band we want, such as 0.5–40 Hz, and drops slow drift and what is too fast to sample Removes every electrode that has noise Adds the brain signal back after the skull weakens it Turns the signal into rows of numbers

6. You want to keep frequencies up to 40 Hz. Which sampling rate is safe? 40 samples a second 256 samples a second 64 samples a second 20 samples a second

All EEG lessons and quizzes · Privacy and your data