Simply EEGLAB
Where the EEG signal comes from
Station 0 · Lesson 1 · EEGLAB 2026.1
Script
nSources = 1000; % number of small sources
srate = 128; % samples per second
t = 0:1/srate:2; % 2 seconds of time
f = 10; % frequency in Hz (alpha range)
phases = 2*pi*rand(nSources, 1);
asyncSum = sum(sin(2*pi*f*t + phases), 1);
syncSum = sum(sin(2*pi*f*t + zeros(nSources, 1)), 1);
fprintf('Peak of random-timing sum: %.0f\n', max(abs(asyncSum)));
fprintf('Peak of synchronized sum: %.0f\n', max(abs(syncSum)));
figure;
plot(t, syncSum); hold on;
plot(t, asyncSum);
xlabel('Time (s)'); ylabel('Summed amplitude (a.u.)');
legend('Synchronized', 'Random timing');Which value should I choose?
| Source | Does it show up in EEG? |
|---|---|
| Postsynaptic potentials in cortical pyramidal cells | Yes, this is the main brain signal |
| Action potentials | Almost never |
| A single cell | No |
| Deep brain structures | Very weak |
| Eye blinks and eye movements | Yes, strongly |
| Muscles (jaw, neck, forehead) | Yes |
| Heart | Sometimes |
| Power line | Yes |