[Eeglablist] difficulties in re-epoching data

[Clayton Hickey]

Hello all,

I'm having some difficulty in re-epoching a dataset.

I'm doing vision research, and want to correct for blink artifacts but 
discard trials in which eye movements took place. I'm currently starting 
analysis by modifying event codes such that relevant conditions are 
identified. I then epoch the data such that all relevant trials are 
selected, and run infomax ICA on this 'grand' dataset. Later, I identify 
components associated with blinks, and components associated with eye 
movements. I remove the components associated with blinks, but discard 
epochs associated with eye movements. I then re-epoch the clean dataset 
such that each condition is stored in its own datafile.

When I re-epoch, I lose a number of trials, sometimes the majority. For 
example, here's the output I receive on one try:

[*code*]
 >> test = pop_epoch(EEG, {'223'}, [-0.5 1.0]);
pop_epoch():212 epochs selected
Epoching...
Warning: event 7 out of data boundary
Warning: event 12 out of data boundary
Warning: event 53 out of data boundary
Warning: event 66 out of data boundary
Warning: event 69 out of data boundary
Warning: event 84 out of data boundary
Warning: event 87 out of data boundary
Warning: event 104 out of data boundary
Warning: event 107 out of data boundary
Warning: event 124 out of data boundary
Warning: event 137 out of data boundary
Warning: event 140 out of data boundary
Warning: event 147 out of data boundary
Warning: event 152 out of data boundary
Warning: event 157 out of data boundary
Warning: event 162 out of data boundary
Warning: event 165 out of data boundary
Warning: event 168 out of data boundary
Warning: event 193 out of data boundary
Warning: event 208 out of data boundary
pop_epoch():192 epochs generated
pop_epoch(): time limits have been adjusted to [-0.500 1.000] to fit 
data points limits
eeg_checkset: recomputing the ICA activation matrix ...
pop_epoch(): checking epochs for data discontinuity
[*end code*]

I'm not sure what it means that the events are out of the data boundary, 
as I'm epoching based on a single event code. I have traced this error 
in epoch.m, but the code is reasonably complicated and I can't quite 
figure out what's going wrong. Has anyone else had similar troubles? Or 
perhaps does anyone have any insight?

Thanks very much,

Clayton Hickey
Vrije Universiteit Amsterdam