Goal is to record clean signals
BCI Components
- Signal acquisition
- Signal processing
- Control signal
- Feedback
- Signal acquisition
Focusing more on signal acquisition…
Collecting Clean Neural Signals
Causes of bad recordings
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Muscle movements
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Other devices
- 60 Hz
-
Sweaty scalps
- Oils and water
- Vanderwal forces?
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Line noise
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ground loop noise
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Electromagnetic interference (EMI)
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Signal processing noise
- Quantization noise
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Mechanical
- temp
- Movement
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Human
-
etc…
Reducing noise
- Reduce as many sources of 60 Hz line noise
- Capacity coupling
- Transfer of electric energy between two insulator-separated conductors
- Signal filters
- Bandpass
- 60 Hz Notch Filter
When you filter… attenuate the signal?
Quality of a neural signal
Generally observed from the power spectrogram
- Fast Fourier Transform (FFT)
- If there are big spikes, means there are artifacts
Cyton Boards
- Dongle
- Board
- Wires
Dongle
Bluetooth connector
Make sure switch is on GPIO option
Dongle should light up if powered
Acquisition Device
Power on, make sure its on PC mode
Power source on backside
Bais (subject ground)
N1P - N8P (electrode signal inputs)
SRB (subject reference)
- Used to cancel noise not originating from the brain
Setup
- Plug in battery pack to the power source (blue light on)
- Power on (PC mode)
- Attach all electrode DuPont ends from…
- SRB -> N1P - N8P -> Bias
- two layers?
Put reference (SRB) on earlobe
- Just cartilledge, not a lot of activity
Put bias ground on mastoid - Could be earlobe too, but mastoid is canonical
Other 8 can go anywhere else according to the 10-20
Weaver Nuprep and Ten20 Application for EEG Electrodes
Yt vid
Download OpenBCI Software
- OpenBCI GUI
- Documentation / Tutorial
- Many options for interfacing
- OpenVibe
- Matlab
- Python