The Visual Evoked Potential is independent of surface alpha rhythm phase

Modulation of Visually Evoked Cortical fMRI Responses by Phase of Ongoing Occipital Alpha Oscillations

“…Residual gradient artifacts present in simultaneous EEG/fMRI measurements prevented us from testing for potential effects in frequencies Ͼ30 Hz that might carry such information (Logothetis, 2008). The effects of alpha phase on the conventional ERP response are hard to assess because the sorting and averaging based on phase introduces phase effects in the ERP even in absence of a stimulus (Klimesch et al, 2009;Risner et al, 2009;Ritter and Becker, 2009). We can therefore only speculate that no such relationship was present in our data given that there was no effect of prestimulus alpha phase on the power of the poststimulus frequencies (i.e., the spectral representation of the ERPs).…”

“…Several studies have successfully linked differences in the shape or power of poststimulus activity to the prestimulus phase of ongoing alpha activity (Bechtereva and Zontov, 1962;Dustman and Beck, 1965;Makeig et al, 2002;Barry et al, 2003). However, this relationship has remained controversial because of the difficulties in unambiguously separating evoked responses from the ongoing activity (Kruglikov and Schiff, 2003;Shah et al, 2004;Yeung et al, 2004;Mazaheri and Jensen, 2006;Klimesch et al, 2009;Risner et al, 2009;Ritter and Becker, 2009).…”

Oscillatory brain states interact with late cognitive components of the somatosensory evoked potential

“…Several theories on the nature of the relationship between ongoing and evoked activities have been proposed (see detailed overviews in Becker et al (2008), Sauseng et al (2007) and note the current debate in Neuroimage (Klimesch et al, 2009;Risner et al, 2009;Ritter and Becker, 2009).…”

Analysis of stimulus-related activity in rat auditory cortex using complex spectral coefficients

“…However, the origin of this variability is still under debate, with some reports arguing that cortical responses can be modeled as a constant additive component combined with variable ongoing activity (Arieli et al 1996;Dawson 1954;Risner et al 2009;Shah et al 2004), whereas others demonstrate that models including variable response components provide superior fits to the data (Truccolo et al 2002). The difference between these models depends on the relative importance of local variable ongoing activity in the cortical network itself, as opposed to variability in ascending input to the network.…”