Stimulus-locked CSD waveforms (220 sample points spanning the time interval from −100 to 995 ms around stimulus-onset) were submitted to temporal PCA (MatLab emulation of BMDP-4M algorithms),42 with an input data matrix consisting of 220 variables and 17,112 observations stemming from 46 participants, 12 conditions (target/nontarget stimuli, tonal/phonetic task, left press/right press/silent count response mode) and 31 electrode sites, including the nose.
