[Eeglablist] Request for Assistance with BioSemi 32-Channel Cap Channel Location Files

[Tavneen Sandhu]

Hello EEGLAB community,
I hope this message finds you well.
I’m relatively new to working with EEGLAB and have been learning as I go. I’m currently using the BioSemi 32-channel cap for my project and have been relying on BioSemi’s Excel file to create my own channel location file. However, I’ve encountered recurring errors throughout my preprocessing pipeline, particularly when trying to calculate ICA weights.
It seems that BioSemi’s method for calculating channel coordinates differs from EEGLAB’s approach, as the theta and sph_theta values keep changing or recalculating when I upload my file. This inconsistency has been a significant obstacle in successfully running the ICA.
Does anyone know how to correctly create a .loc or .ced file so that this issue (where the values are being recalculated) doesn’t occur and the file can be properly read by EEGLAB? Alternatively, if anyone already has a .loc or .ced file with the correct channel locations for the BioSemi 32-channel cap that integrates well with EEGLAB, I would be incredibly grateful if you could share it. Any additional tips or guidance for troubleshooting these issues as a newcomer to EEGLAB would also be greatly appreciated.
Thank you so much for your time and support!
Best regards,
Tavneen Sandhu
MSc Student, Queen’s University