Table 1: Results of the repeated measures ANOVA pre-cue condition by experimental phase are shown for each ROI. precun = precuneus, occip-par = occipito-parietal, inf-temp = inferior-temporal, hMT+ = human middle temporal.
The left column of Figure 5B shows the mean relative power ssVEF modulations for the pre-cue baseline, post-cue not attended and attended conditions separated by the pre-cue condition (attend peripheral rings vs. attend central fixation cross). The interaction pre-cue condition by experimental phase in V1, V2, precuneus, and occipito-parietal cortex was explained by bigger ssVEF modulations by spatial attention to the cued visual hemifield when the central fixation cross was attended during the pre-cue baseline compared to when the peripheral rings had been attended (t-tests between the modulation differences V1: t(19) = 2.69, p = 0.014, Cohen’s d = 0.60; V2: t(19) = 2.53, p = 0.020, Cohen’s d = 0.57; precuneus: t(19) = 2.59, p = 0.018, Cohen’s d = 0.58; occipito-parietal cortex: t(19) = 2.39, p = 0.027, Cohen’s d = 0.54; see Figure 5B).
However, this was not the case for the hMT+ and inferior-temporal cortical areas (hMT+: t(19) = 1.33, p = 0.20, Cohen’s d = 0.30; inferior-temporal cortex: t(19) = 0.77, p = 0.45, Cohen’s d = 0.17). Critically, when the participants attended the central fixation cross during the pre-cue baseline, the peripheral ring flickers did not evoke greater ssVEF responses than when spatial attention was directed away to the cued visual hemifield (not attended post-cue condition) in these brain regions. However, this modulation difference was greater when participants attended the peripheral rings during the pre-cue baseline (t-tests between the modulation differences hMT+: t(19) = 3.10, p = 0.006, Cohens’ d = 0.69; inferior-temporal cortex: t(19) = 2.83, p = 0.011, Cohen’s d = 0.63; see Figure 5B).
Finally, given the ssVEF modulation patterns in each ROI (see Figure 5), the two pre-cue baseline conditions (rings vs. cross) were compared directly for each ROI, separately. In V1, V2, and precuneus no differences were observed (ps > 0.05), whereas in the occipito-parietal area attending to both peripheral rings elicited greater ssVEF responses than when attending to the fixation cross changes (t(19) = 2.15, p = 0.045, Cohen’s d = 0.48). This effect was pronounced in hMT+ (t(19) = 3.13, p = 0.006, Cohen’s d = 0.70) and inferio-temporal cortex (t(19) = 2.39, p = 0.027, Cohen’s d = 0.53).