P1 and Traveling Alpha Waves: Evidence for Evoked Oscillations

Abstract

Klimesch W, Hanslmayr S, Sauseng P, Gruber WR, Doppelmayr M. P1 and traveling alpha waves: evidence for evoked oscillations. J Neurophysiol 97: [1311][1312][1313][1314][1315][1316][1317][1318] 2007. First published December 13, 2006; doi:10.1152/jn.00876.2006. The hypothesis is tested whether the P1 of the event-related potential (ERP) component behaves like an evoked, traveling alpha wave. This hypothesis is based on different kinds of evidence showing, e.g., that-after undergoing phase reorganization-frequencies in the broad alpha range become synchronized (aligned) in absolute phase and contribute significantly to the generation of the P1. We investigated data from a Stroop task in which subjects had to respond only to the color and ignore the meaning of the presented words. Analyzing topographical phase relationships expressed in terms of traveling speed (with respect to Pz as trailing site) revealed that a systematic posterior to anterior traveling pattern appeared only in the broad time window of the P1-N1 complex and in the extended alpha frequency range. The obtained findings are consistent with the oscillatory ERP model and suggest that the P1 component may be considered a manifestation of an evoked, traveling alpha wave. We assume that the P1 reflects a top-down process in a sense that traveling alpha waves control or "gate" the direction of information processing in the brain. In this paper, we focus on P1 latency and the hypothesis that the P1 component behaves like an evoked, traveling alpha wave. This hypothesis is based on the following evidence, linking alpha and early evoked activity. First, we have observed that P1 latency is correlated with individual alpha frequency (IAF) in a sense that short latencies are associated with high IAF and long latencies with low IAF (Klimesch et al. 2004). Second, it was found that evoked oscillations-particularly in the alpha and theta frequency range-become synchronized (aligned) in absolute phase during small time windows that coincide with the latencies of the P1-N1 complex (Gruber et al. 2005;Mormann et al. 2005). We were able to demonstrate that the latencies of the P1 and N1 can be predicted at least in part by a phase alignment between different frequencies particularly in the alpha but also theta frequency range. Third, analyzing m:n phase coupling revealed that coupling between alpha and theta was largest during the time window of the P1-N1 complex (Schack et al. 2005). Fourth, growing evidence supports the oscillatory EEG model, suggesting that early evoked potentials (and the P1 in particular) are generated (at least in part) by a reorganization of phase and not by a superposition of an evoked component on ongoing oscillations with random phase (Barry et al. 2000;Basar 1999;Hanslmayr et al. 2007).These findings suggest that the P1 may be described in terms of an evoked oscillation and raise an interesting question with respect to the topography of P1 latency differences. If the P1 is generated (at least in part) by oscillations in the alpha frequenc...

Dissociating the Effect of Noise on Sensory Processing and Overall Decision Difficulty

“…The ITC provides a measure for the degree of phase locking for a specific oscillation to a stimulus, and it has been shown that phase-locked oscillations might modulate ERP components (Klimesch et al, 2004;Hsiao et al, 2006;Klimesch et al, 2007;Rousselet et al, 2007;Freunberger et al, 2009). Furthermore, improved temporal coordination within and across task-related brain regions may be an important mechanism underlying fast and efficient behavioral performance (Ghuman et al, 2008;Gilbert et al, 2010).…”

The Decoupled Mind: Mind-wandering Disrupts Cortical Phase-locking to Perceptual Events

“…The time window for detecting peak amplitude of the P1 component was 50-150 msec (e.g., Klimesch, Hanslmayr, Sauseng, Gruber, & Doppelmayr, 2007). For visualization of ERPs, we applied a 30-Hz linear low-pass filter.…”

Traveling Waves in the Human EEG during Voluntary Hand Movements

“…Phase shifts in potentials therefore have great potential for BMI. The informativeness of time lags is also supported by studies of vision (see, for example, [Klimesch et al, 2007]). In relation to brain-machine interfaces, the movement of LFP in the primary motor and dorsal premotor areas of the cortex has already been studied in monkeys in a "reaching task" [Rubino et al, 2006].…”

“…Apart from the low spatial resolution of the EEG (as compared with LFP), the reason for this would appear to be that the spectral parameters used are indirectly related to the information processes of sensorimotor encoding. Movement of the potential wave is now believed to be directly related to encoding [Tsitseroshin and Shepoval'nikov, 2009;Ermentrout and Kleinfelt, 2001;Klimesch et al, 2007;Lopes da Silva, 1989;Lubenov and Siapas, 2009] and there are many reports of their links with motor functions and visual perception [Bark et al, 2005;Shevelev et al, 2002;Rubino et al, 2006;and others]. In particular, we cannot fail to note the often cited work of Nicolelis et al [Lebedev and Nicolelis, 2006;Nicolelis et al, 1995;Petermann et al, 2009] on sensorimotor encoding in hand movements in monkeys and in whisker movements in rats in conditions of free behavior.…”