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Dear Marco, It would be better to use normal or fine mesh if your computer power allows it. I think these days there is no reason to use coarse, just when SPM8 first came out there were still many old an weak machines around. Hanning window indeed multiplies the response in time and suppresses the edges. If the interesting part of the response is in the middle of your time window it would be advisable to use it. Best, Vladimir On 25 Sep 2012, at 16:16, Marco Buiatti wrote: > Dear SPM masters, > > I am trying to perform source reconstruction on the grand-averaged > ERPs from an EEG study (BrainAmp, 64 channels) with 20 subjects. Since > the EEG electrode positions were not digitized, I am using the > standard EEG template with standard electrode positions. > > My problem is that I see a quite wide variability in the sources by > varying two parameters of the reconstruction: > 1) use of coarse or normal cortical mesh > 2) use or not of hanning window when inverting > > My questions are: > 1) Is it normal to see large variability when using normal or coarse > mesh? What would be the best for 64 electrodes? > 2) What does the hanning window exactly refers to? I intuitively think > that data in time are weighted by this window, but I could not find > the exact info on the manual. > 3) Any other important factor that you think is crucial for source > reconstruction in this case? > > Thanks for your feedback, > > Best, > > Marco > > -- > Marco Buiatti, PhD > > CEA/DSV/I2BM / NeuroSpin > INSERM U992 - Cognitive Neuroimaging Unit > Bāt 145 - Point Courrier 156 > Gif sur Yvette F-91191 FRANCE > Ph: +33(0)169.08.65.21 > Fax: +33(0)169.08.79.73 > E-mail: [log in to unmask] > http://www.unicog.org/pm/pmwiki.php/Main/MarcoBuiatti > > ***********************************************