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. Author manuscript; available in PMC: 2016 Dec 23.
Published in final edited form as: J Child Psychol Psychiatry. 2015 Jun 23;57(1):4–17. doi: 10.1111/jcpp.12435

Figure 2.

Figure 2

Insufficiency of the ERP model. (A) Color-indicated single trials time locked to participant button presses in a cognitive task paradigm (channel: Cz to average reference). The trials are sorted (bottom to top) in increasing order of mean potential in a (dashed-line indicated) postresponse latency window and lightly smoothed with a 20-trial moving average. The trial-average ERP is shown below the ERP-image panel. The prominent postresponse positivity in the ERP actually occurs in less than 80% of the single trials. (B) The trial-average ERP regressed on each trial activity, plotted in the same trial order. The model trial average, shown below, matches the actual trial ERP. (C) The difference between the data in panels A and B shows that activity in the postresponse latency window, for a subset of most positive-going and negative-going (top and bottom) trials, is not proportional to the expression of the whole ERP in those trials. (Reprinted from Makeig & Onton, 2012, which also shows many other phenomena in these data not evident in this figure)