A quick scan of search results seems to indicate that the highest density EEG systems on the market are limited to 256 channels such as Neuvo, SynAmps, and others. Is this an arbitrary limit (either due to system design or practicality of sensor placement) or is it perhaps a case of diminishing returns with any decreased sensor spacing not providing much in the way of additional information in the data points?
If not 256 channels then what would be an upper limit? Am I correct in assuming that the summation of electrical activity that is expressed at the scalp would be spatially quantized due the raised gyri on the brain surface (with any activity in the intervening sulci being masked)? Then again if that were the case would there still be benefit in having the extra spatial resolution running atop the contours of the gyri?
I'm wondering if a system consisting of a full mesh of electrodes would have merit as a project? [this would be for those such as myself that due to either nature or grooming don't have to work around any hair on there scalp]