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. 2019 Apr 30;17(4):e3000233. doi: 10.1371/journal.pbio.3000233

Fig 4. Attention modulates MSPCres but not MSPCstim.

Fig 4

MSPC averaged across the two second-order IM components of the attended and the unattended images. (Note that within each trial, different SWIFT frequencies were used for the attended and the unattended images, each resulting in a different set of second-order IMs.) Results are shown for a posterior ROI (17 electrodes, top) and the scalp topographies (bottom). Error bars represent standard error across subjects (N = 11). The MSPCstim measure (left) quantifies IM responses by examining the degree to which the IM phase is driven by the phases of the SWIFT and SSVEP stimulus (image) modulations. Conversely, the MSPCres measure (right) examines the degree to which the IM phase is driven by the tagged SWIFT and SSVEP neural response phases. MSPCres (right) was higher for the attended compared to the unattended images (χ2 = 41.4, P < 0.001), indicating increased neural integration between the SWIFT and SSVEP signals when stimuli are attended. This effect was not evident for the MSPCstim measure (χ2 = 1.21, P > 0.05). The data underlying this figure is available in FigShare at DOI: 10.26180/5b9abfe5687e3. IM, intermodulation; MSPCres, multispectral phase coherency (response); MSPCstim, MSPC (stimulus); ROI, region of interest; SSVEP, steady-state visual evoked potentials; SWIFT, semantic wavelet-induced frequency-tagging.