Subsecond changes of global brain state in illusory multistable motion perception

Abstract

This study explored transient changes in EEG microstates and spatial Omega complexity associated with changes in multistable perception. 21-channel EEG was recorded from 13 healthy subjects viewing an alternating dot pattern that induced illusory motion with ambiguous direction. Baseline epochs with stable motion direction were compared to epochs immediately preceding stimuli that were perceived with changed motion direction ('reference stimuli'). About 750 ms before reference stimuli, Omega complexity decreased as compared to baseline, and two of four classes of EEG microstates changed their probability of occurrence. About 300 ms before reference stimuli, Omega complexity increased and the previous deviations of EEG microstates were reversed. Given earlier results on Omega complexity and microstates, these sub-second EEG changes might parallel longer-lasting fluctuations in vigilance. Assumedly, the discontinuities of illusory motion thus occur during sub-second dips in arousal, and the following reconstruction of the illusion coincides with a state of relative over-arousal.

A pharmaco-EEG study on antipsychotic drugs in healthy volunteers

“…Figure 2 shows the mean topographies of the four microstate classes obtained from all EEG data and the percent total time covered by each state. These overall results closely replicated previous work (Koenig et al , 2002Strelets et al 2003;Lehmann et al 2005;Mueller et al 2005) and were therefore labeled and arranged in the same order as in previous publications (Koenig et al , 2002. Microstates of class A had a left occipital to right frontal orientation, class B was from right occipital to left frontal, class C had a symmetric occipital to prefrontal orientation, and class D was also symmetric but with a frontocentral and an occipital maximum of absolute voltage.…”

“…As topography remains stable around peaks of GFP and changes during the troughs, only topographies at momentary maxima of the GFP were further analyzed (Lehmann et al 1987;Strik and Lehmann 1993;Wackermann et al 1993). As in previous works (Koenig et al , 2002Strelets et al 2003;Lehmann et al 2005;Mueller et al 2005), four optimally fitted microstate class topographies were obtained from all data of EEG using a modified version of the k-mean clustering algorithm (Pascual-Marqui et al 1995). The algorithm was instructed to seek four classes of microstate topography and to assign each topography of EEG to one of these classes.…”

“…An alternative and complementary approach is microstate analysis, where the time-domain EEG is parsed into sub-second periods of quasi-stable field topography (Lehmann et al 1987). As in resting EEG, microstate topographies tend to concentrate around a small number of prototypical configurations; they can be efficiently clustered, and subsequent statistics can be done depending on the cluster membership of the microstates (Koenig et al , 2002Strelets et al 2003;Mueller et al 2005).…”

On the meaning and interpretation of global descriptors of brain electrical activity. Including a reply to X. Pei et al.

“…During the last decade, the global approach has been applied in clinical neurophysiology (Stam et al, 2000;Kim et al, 2003;Kondákor et al, 2005;Molnár et al, 2006), psychopathology and neuropsychiatry (Pizzagalli et al, 2000;Tóth et al, 2004;Yoshimura et al, 2004;Irisawa et al, 2006), in studies of perceptual and cognitive processes (Bhattacharya, 2000;Bhattacharya et al, 2001;Müller et al, 2005), sensorimotor control (Stančák and Wackermann, 1998;Stančák et al, 2002), emotions and altered states of consciousness (Isotani et al, 2002), etc. These studies focused almost exclusively on the spatial complexity, Ω, of mEEG; the results were often interpreted in terms of long-range synchrony between local EEG activities (Bhattacharya et al, 2001;Kondákor et al, 2005).…”

From EEG dependency multichannel matching pursuit to sparse topographic EEG decomposition

“…durations of microstates of some typical configuration became feasible. In normal subjects, EEG microstate topography has been shown to indicate different cognitive modes (Lehmann et al, 1998;Mueller et al, 2004), maturational states (Koenig et al, 2002) and abnormal conditions including dementia (Strik et al, 1997;Dierks et al, 1997) or schizophrenia (Koenig et al, 1999;Lehmann et al, 2005).…”