Meg planar

[Marie Smith]

Dear all,

I want to use the planar gradient correction computed on individual
trials as opposed to the average trial and i am getting some strange
results. When i compute the planar gradient on the average of the
trials, it seems to make sense wrt the original data (bottom plot,
chans*time), however when the single trials are taken into account
the new planar averaged seems to be very smeared into the baseline
region (top plot). Even though the baseline has already been removed
from every trial.

Is this just a result of noise in the single trials and is there any
way to correct for it? Looking at the statistics tutorial data this
does not seem to be an issue for that data set, could it be caused by
some sort of artifacts that i have not taken into account?

Thanks,

Marie


Script info:

cfg.keeptrials = 'yes';
cfg.baseline = [-0.2 0];
avg = timelockanalysis(cfg, data);
avg = timelockbaseline(cfg,avg);
pl = megplanar(cfg, avg);
plcb = combineplanar(cfg, pl);

cfg = [];
cfg.keeptrials = 'no';
cfg.baseline = [-0.2 0];
avg = timelockanalysis(cfg, data);
avg = timelockbaseline(cfg,avg);
pl = megplanar(cfg, avg);
plcb = combineplanar(cfg, pl);



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