Single Doses of Piracetam Affect 42-Channel Event-Related Potential Microstate Maps in a Cognitive Paradigm

Michel, Christoph M.; Lehmann, Dietrich

doi:10.1159/000119026

Cited by 31 publications

(9 citation statements)

References 15 publications

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“…In the present analysis, the map topographies were assessed by a feature extraction that resulted in the centroid descriptors. It has been shown that the latencies of the microstates are closely similar if the maps are compared directly by correlating their voltage distributions (full topographic information applying Global Map Dissimilarity) instead of the extracted spatial features and even if the latencies of the distribution-independent Global Field Power minima are used as in Michel and Lehmann (1993).…”

Section: Discussionmentioning

confidence: 99%

Microstates in Language-Related Brain Potential Maps Show Noun–Verb Differences

Koenig¹,

Lehmann²

1996

Brain and Language

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149

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Brain processing of grammatical word class was studied analyzing event-related potential (ERP) brain fields. Normal subjects observed a randomized sequence of single German nouns and verbs on a computer screen, while 20-channel ERP field map series were recorded separately for both word classes. Spatial microstate analysis was applied, based on the observation that series of ERP maps consist of epochs of quasi-stable map landscapes and based on the rationale that different map landscapes must have been generated by different neural generators and thus suggest different brain functions. Space-oriented segmentation of the mean map series identified nine successive, different functional microstates, i.e., steps of brain information processing characterized by quasi-stable map landscapes. In the microstate from 116 to 172 msec, noun-related maps differed significantly from verb-related maps along the left-right axis. The results indicate that different neural populations represent different grammatical word classes in language processing, in agreement with clinical observations. This word class differentiation as revealed by the spatialtemporal organization of neural activity occurred at a time after word input compatible with speed of reading.

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Section: Discussionmentioning

confidence: 99%

Microstates in Language-Related Brain Potential Maps Show Noun–Verb Differences

Koenig¹,

Lehmann²

1996

Brain and Language

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149

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“…They observed single digits appearing on a screen in a pseudo-random order, and they were requested to press a microswitch whenever the last three digits were either odd or even ("triplets"; Michel and Lehmann, 1993). The single digits subtended 1.5 degrees visual angle, and were presented at intervals of 704ms; each was shown for 100ms duration.…”

Section: Methodsmentioning

confidence: 99%

“…Only those stimuli were used which are expected to elicit similar and relatively simple cognitive processing without specific anticipations such as represented by the contingent negative variation (McCallum, 1988) and without responses to occurrences or nonoccurrences of expected targets ("update", "closure", "mismatch"; Kutas and Hillyard, 1980;Picton, 1992;Michel and Lehmann, 1993). Within the series of the presented odd (O) or even (E) digit stimuli, a new stimulus may (1) follow an O-E-or E-O-sequence.…”

Section: Analyzed Datamentioning

confidence: 99%

“…The functional state of the human brain is very sensitively reflected by its electrical activity, i.e., by the spontaneous electroencephalogram (EEG) or the event-related potentials (ERPs) as reported in many papers (e.g., Lehmann, 1968, 1983;John et al, 1988). Different ERP waveforms have been observed depending on the factors mentioned above (e.g., Chourchesne, 1978;Friedman et al, 1990;Koelega and Verbaten, 1991;Takeda et al, 1992;Michel and Lehmann, 1993;Nfifitfinen et al, 1993;Woods, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Prestimulus EEG microstates influence visual event-related potential microstates in field maps with 47 channels

Kondákor¹,

Lehmann²,

Michel

et al. 1997

J. Neural Transmission

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The influence of the immediate prestimulus EEG microstate (sub-second epoch of stable topography/map landscape) on the map landscape of visually evoked 47-channel event-related potential (ERP) microstates was examined using the frequent, non-target stimuli of a cognitive paradigm (12 volunteers). For the two frequent prestimulus microstate classes (oriented left anterior-right posterior and right anterior-left posterior), ERP map series were selectively averaged. The post-stimulus ERP grand average map series was segmented into microstates; 10 were found. The centroid locations of positive and negative map areas extracted as landscape descriptors. Significant differences (MANOVAs and t-tests) between the two prestimulus classes were found in four of the ten ERP microstates. The relative orientation of the two ERP microstate classes was the same as prestimulus in some ERP microstates, but reversed in others. Thus, brain electric microstates at stimulus arrival influence the landscapes of the post-stimulus ERP maps and therefore, information processing; prestimulus microstate effects differed for different post-stimulus ERP microstates.

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“…The evaluation of ERPs was performed by microstate analysis. This analysis is based on the observation that the brain electrical field (EF) on the scalp (map) stays nearly stable over a time segment (microstate) followed by a sudden change of EF characterizing the next microstate [Michel and Lehmann, 1993;Pascual-Marqui et al, 1995b]. Different landscapes of the maps indicate different configurations of the activated neural population and therefore partially reflect different functional microstates of the brain [Brandeis and Lehmann, 1989;Michel and Lehmann, 1993].…”

Section: Introductionmentioning

confidence: 99%

Effects of weak mobile phone—Electromagnetic fields (GSM, UMTS) on event related potentials and cognitive functions

Kleinlogel

Dierks

Koenig

et al. 2008

Bioelectromagnetics

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Modern mobile phones emit electromagnetic fields (EMF) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. Until now most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies have focused on Universal Mobile Telecommunications System (UMTS)-EMF. Therefore, we tested the effects of both types of unilaterally presented EMF, 1950 UMTS (0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on visually evoked occipital P100, the P300 of a continuous performance test, auditory evoked central N100 and the P300 during an oddball task as well as on the respective behavioral parameters, reaction time and false reactions, in 15 healthy, right handed subjects. A double-blind, randomized, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.

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Single Doses of Piracetam Affect 42-Channel Event-Related Potential Microstate Maps in a Cognitive Paradigm

Cited by 31 publications

References 15 publications

Microstates in Language-Related Brain Potential Maps Show Noun–Verb Differences

Microstates in Language-Related Brain Potential Maps Show Noun–Verb Differences

Prestimulus EEG microstates influence visual event-related potential microstates in field maps with 47 channels

Effects of weak mobile phone—Electromagnetic fields (GSM, UMTS) on event related potentials and cognitive functions

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