Table 1 Analysis of the early negative and the late positive event-related potentials

From: Fluctuations in instantaneous frequency predict alpha amplitude during visual perception

 

Early negative deflection

Late positive deflection

Contralateral vs ipsilateral

*t(15) = −3.435, p = 0.0001

* t(15) = 2.129, p = 0.0499

Accuracy, contralateral electrodes

t = −1.745, p = 0.0984

*i(15) = 6.548, p = 0.0

Accuracy, ipsilateral electrodes

t = 1.258, p = 0.2281

*t(15) = 7.028, p = 0.0

Location×accuracy interaction

*t(15) = −3.053, p = 0.01

t(15) = −1.244, p = 0.2301

  1. First, data were analyzed as a function of the location of electrodes with respect to the target (i.e., the amplitude of ERP responses in electrodes that were contralateral or ipsilateral to the target). Next, comparisons were made between correct and incorrect trials, separately for contralateral and ipsilateral electrodes. Finally, the interaction between electrode position (contralateral/ipsilateral) and behavioral accuracy was assessed. Note that all statistical tests are reported as t-tests on difference scores instead of F-values that would be obtained in an analysis of variance (ANOVA). This was done to maintain consistency across comparisons, and produces identical outcomes (t is the square root of F in this situation). All tests report t-tests on the average amplitude values within pre-defined 50 ms windows from 210–260 and 460–510 ms post stimulus for the END and LPD, respectively. t-values were compared against distributions obtained empirically by randomizing condition labels 10,000 times and then repeating the same statistical test (see Methods). * indicates a significant effect at p = 0.05
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