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. Author manuscript; available in PMC: 2016 Oct 1.
Published in final edited form as: J Cogn Neurosci. 2016 Mar 11;28(7):935–947. doi: 10.1162/jocn_a_00949

Figure 5. The instantaneous amplitude (IA) of the SSVEP over time.

Figure 5

Topographic plots represent data from epochs time-locked (A) to the onset of Nontarget stimuli in the absence of Distractors, (B) to the onset of Nontargets when Distractors occurred (Distractor onsets 0–116 ms relative to Nontarget onset, corrected for sensory activity of the Distractor itself; see Methods for additional details), and (C) the difference between these two conditions. Note no pre-Distractor baseline correction was performed on these data. As is clear in the maps, the IAs were the largest over posterior channels. For the Nontarget-without-Distractor condition, data from 3 RSVP runs without distraction were used. D) The extracted timecourse of the IA. Data are the IA values over time averaged within a posterior ROI (illustrated). Without Distractors, the IA of the envelope of the SSVEP generated by the RSVP task stream remained nearly constant over time. In contrast, Distractor presentation resulted in a modulation of the SSVEP envelope (lower amplitude), implicating reduced attentional allocation to the RSVP stream.