Experiment 1: L-TRF and F-TRF responses showed distinct neuronal spatiotemporal profiles.

<p>(A) L-TRF responses. (B) F-TRF responses. Note that the TRF responses represent brain responses to each unit transient in luminance (L-TRF) or global form coherence (F-TRF) of the glass pattern sequences. Upper panel: Grand average (<i>n</i> = 20) plots for TRF waveforms (summarized as root-mean-square across all MEG channels) as a function of temporal lag (−100 to 400 ms). Gray shades indicate the confidence interval after permutation test (see details in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2003646#pbio.2003646.s001" target="_blank">S1 Text</a>). Error bar indicates the standard error. Middle panel: Grand average (<i>n</i> = 20) plots for sensor-level topographical distribution of TRF responses at 0–100, 100–200, and 200–300 ms time range. Lower panel: Grand average (<i>n</i> = 20) plots for TRF source localization results in the normalized MNI template at 0–100, 100–200, and 200–300 ms time range (cluster-level permutation test across space and time, multiple comparison corrected, cluster <i>p</i> < 0.05). The MNI coordinates for the significant source clusters are listed in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2003646#pbio.2003646.s003" target="_blank">S1 Table</a>. It is notable that F-TRF activated the IPS and V3a within the first 100 ms, followed by responses in primary visual cortices in the next 100 ms, in accordance with a reversed high-to-low activation pattern. Meanwhile, L-TRF showed a feedforward profile that started from EVAs. The data underlying Fig 2 can be found in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2003646#pbio.2003646.s005" target="_blank">S1 Data</a>. EVAs, early visual areas; F-TRF, form coherence TRF; IPS, intraparietal sulcus; L-TRF, luminance TRF; MEG, magnetoencephalography; MNI, Montreal Neurological Institute; n.s., not significant.