Change in display waveforms

Discussions
1

Hello everyone,

I am working with a dataset of 582 (intracranial) electrodes that looks like this when I import it:

image
image1917×569 122 KB

As you can see the unit on the y-axis is µV. I would like to display the voltage map of those waveforms, therefore I need to allocate the location of each electrode (the MNI coordinates are available). However, after I did that, the waveforms are displayed in a different unit on the y-axis and they also look different:
image
image1912×493 75.1 KB

This happens automatically, I haven't changed the settings of the montage.

Does anyone know what happened to the data? How can I look at the waveforms again in µV?

Many thanks for your help!

Kind regards,

Joyce

2

The polarity of the time series got inverted (negative up vs. down, depending on EEG conventions). Make sure you toggle the button indicated by the red arrow in the following screenshots.

f97539f6008fb84eb3d4095bd9a1fefd13a681a7
f97539f6008fb84eb3d4095bd9a1fefd13a681a71912×493 100 KB

3

Hello Sylvain,

thank you for your quick response, that seems to work! It is not very important, but do you know why the y-axis changes from µV to 10^-5? I know it basically comes down to the same thing, but I am just curious :slight_smile:

Many thanks!