[Eeglablist] Low density system questions

[Fran Copelli]

Hi Scott — thanks for your reply — but the system is actually the Starstim 20 from Neuroelectrics; we are using 18 scalp channels following a 1020 system layout. I’m not sure if the same rule applies to this system— can you advise? 


> On May 2, 2020, at 4:45 PM, Scott Makeig <smakeig at gmail.com> wrote:
> 
> 
> If you are using a Biosemi system (with CMS-DRL electrodes) then you must re-reference to eliminate a <=40 dB noise contamination (see the Biosemi website). You may reference as you wish -- using average reference is typically a good choice.
> 
> Scott Makeig
> 
>> On Sat, May 2, 2020 at 8:40 AM Fran Copelli <fcopelli at ryerson.ca> wrote:
>> Dear list,
>> 
>> My colleague is collecting data using a low density (18 channel) system.
>> With so few channels, what are the guidelines regarding a) whether noisy
>> channels should be deleted or interpolated and b) what is the maximum value
>> to remove and still have interpretable data.
>> 
>> My second question is regarding referencing. The manual for the system
>> suggests that all data is referenced to CMS. Should we be rereferencing to
>> another channel/to the average? Is average referencing suitable for such a
>> low density system? Note that there are no mastoids to reference, only
>> scalp and eye channels.
>> 
>> 
>> Thanks very much and looking forward to hearing any suggestions,
>> 
>> Fran
>> 
>> Fran
>> 
>> SMART Lab, Psychology Department
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> 
> 
> -- 
> Scott Makeig, Research Scientist and Director, Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla CA 92093-0559, http://sccn.ucsd.edu/~scott