EEG source localisation no activation even at 0% amplitude...?

Hello Brainstormers,

I am analyzing cortical auditory evoked potentials (CAEP) and faced something peculiar that I would like some thoughts on. Below middle is the averaged CAEP from 389 trials of 1 kHz tone burst (11 trials were discarded due to data quality) at 60 dBnHL. And the right is the corresponding sensor-level topography. The bottom middle is supposed to be showing the corresponding source level activation in the areas of the primary auditory cortex but currently isn't.

The amplitude threshold is currently set to 0% so I should be seeing something but I am not seeing anything at all. What might be the potential reasons for this?

Please bring the min size slider down to 0 and make sure the maximum of the color scale is set to 'Local'. The numbers look very small but we'll see after you proceed as indicated -- thanks!

Thank you for these suggestions! I've done as suggested but there is no difference. I've also attached below the input used for sLORETA. I've also tried reimporting the individual trials - running average on the trials - compute sources again but nothing changed either.


Interestingly, some other conditions (e.g. different stimulus intensity) from the same subject also show the same observation of no source activations with stimulus presentation (and with all conditions being equal). Therefore I did some investigation and I've found the following. Below is the error message you get when you try to display the scout time series with the selected scouts (right BA 41 and 42). Perhaps this error message may give some insight as to what is going on...? (or is this just saying that there is nothing to display because there are no displayable source activations?)

This matter has been resolved in the forum below: