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Wolfgang Klimesch - One of the best experts on this subject based on the ideXlab platform.
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Lexical access and evoked traveling Alpha Waves
NeuroImage, 2014Co-Authors: Andrea Zauner, Walter Gruber, Nicole Alexandra Himmelstoß, Julia Lechinger, Wolfgang KlimeschAbstract:Retrieval from semantic memory is usually considered within a time window around 300–600 ms. Here we suggest that lexical access already occurs at around 100 ms. This interpretation is based on the finding that semantically rich and frequent words exhibit a significantly shorter topographical latency difference between the site with the shortest P1 latency (leading site) and that with the longest P1 latency (trailing site). This latency difference can be described in terms of an evoked traveling Alpha Wave as was already shown in earlier studies.
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Evoked traveling Alpha Waves predict visual-semantic categorization-speed
NeuroImage, 2011Co-Authors: Robert Fellinger, Andrea Zauner, Walter Gruber, Roman Freunberger, Wolfgang KlimeschAbstract:In the present study we have tested the hypothesis that evoked traveling Alpha Waves are behaviorally significant. The results of a visual-semantic categorization task show that three early ERP components including the P1–N1 complex had a dominant frequency characteristic in the Alpha range and behaved like traveling Waves do. They exhibited a traveling direction from midline occipital to right lateral parietal sites. Phase analyses revealed that this traveling behavior of ERP components could be explained by phase-delays in the Alpha but not theta and beta frequency range. Most importantly, we found that the speed of the traveling Alpha Wave was significantly and negatively correlated with reaction time indicating that slow traveling speed was associated with fast picture-categorization. We conclude that evoked Alpha oscillations are functionally associated with early access to visual-semantic information and generate – or at least modulate – the early Waveforms of the visual ERP.
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pre stimulus Alpha phase alignment predicts p1 amplitude
Brain Research Bulletin, 2011Co-Authors: Robert Fellinger, Wolfgang Klimesch, Walter Gruber, Roman Freunberger, Michael DoppelmayrAbstract:Since years there is a hotly discussed dispute whether event-related potentials are either generated by an evoked component or by resetting of ongoing phase. We argue that phase-reset must not be proven in order to accept the general involvement of phase in ERP-generation as it is only one of several possible mechanisms influencing or generating certain ERP-components. Supporting data are presented showing that positive peaks of ongoing pre-stimulus Alpha activity are not randomly distributed in time across trials. Most importantly, we found that a certain kind of pre-stimulus phase concentration that represents a continuous development of an Alpha Wave up to the time window where the P1 is generated is associated with an enlarged event-related component. We conclude that ongoing oscillations cannot be considered random background noise (even before stimulus onset) and that there are probably more phase-mechanisms that can contribute to the ERP-generation.
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P1 and Traveling Alpha Waves: Evidence for Evoked Oscillations
Journal of neurophysiology, 2006Co-Authors: Wolfgang Klimesch, Simon Hanslmayr, Paul Sauseng, Walter Gruber, Michael DoppelmayrAbstract: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,...
Walter Gruber - One of the best experts on this subject based on the ideXlab platform.
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Lexical access and evoked traveling Alpha Waves
NeuroImage, 2014Co-Authors: Andrea Zauner, Walter Gruber, Nicole Alexandra Himmelstoß, Julia Lechinger, Wolfgang KlimeschAbstract:Retrieval from semantic memory is usually considered within a time window around 300–600 ms. Here we suggest that lexical access already occurs at around 100 ms. This interpretation is based on the finding that semantically rich and frequent words exhibit a significantly shorter topographical latency difference between the site with the shortest P1 latency (leading site) and that with the longest P1 latency (trailing site). This latency difference can be described in terms of an evoked traveling Alpha Wave as was already shown in earlier studies.
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Evoked traveling Alpha Waves predict visual-semantic categorization-speed
NeuroImage, 2011Co-Authors: Robert Fellinger, Andrea Zauner, Walter Gruber, Roman Freunberger, Wolfgang KlimeschAbstract:In the present study we have tested the hypothesis that evoked traveling Alpha Waves are behaviorally significant. The results of a visual-semantic categorization task show that three early ERP components including the P1–N1 complex had a dominant frequency characteristic in the Alpha range and behaved like traveling Waves do. They exhibited a traveling direction from midline occipital to right lateral parietal sites. Phase analyses revealed that this traveling behavior of ERP components could be explained by phase-delays in the Alpha but not theta and beta frequency range. Most importantly, we found that the speed of the traveling Alpha Wave was significantly and negatively correlated with reaction time indicating that slow traveling speed was associated with fast picture-categorization. We conclude that evoked Alpha oscillations are functionally associated with early access to visual-semantic information and generate – or at least modulate – the early Waveforms of the visual ERP.
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pre stimulus Alpha phase alignment predicts p1 amplitude
Brain Research Bulletin, 2011Co-Authors: Robert Fellinger, Wolfgang Klimesch, Walter Gruber, Roman Freunberger, Michael DoppelmayrAbstract:Since years there is a hotly discussed dispute whether event-related potentials are either generated by an evoked component or by resetting of ongoing phase. We argue that phase-reset must not be proven in order to accept the general involvement of phase in ERP-generation as it is only one of several possible mechanisms influencing or generating certain ERP-components. Supporting data are presented showing that positive peaks of ongoing pre-stimulus Alpha activity are not randomly distributed in time across trials. Most importantly, we found that a certain kind of pre-stimulus phase concentration that represents a continuous development of an Alpha Wave up to the time window where the P1 is generated is associated with an enlarged event-related component. We conclude that ongoing oscillations cannot be considered random background noise (even before stimulus onset) and that there are probably more phase-mechanisms that can contribute to the ERP-generation.
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P1 and Traveling Alpha Waves: Evidence for Evoked Oscillations
Journal of neurophysiology, 2006Co-Authors: Wolfgang Klimesch, Simon Hanslmayr, Paul Sauseng, Walter Gruber, Michael DoppelmayrAbstract: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,...
Robert Fellinger - One of the best experts on this subject based on the ideXlab platform.
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Evoked traveling Alpha Waves predict visual-semantic categorization-speed
NeuroImage, 2011Co-Authors: Robert Fellinger, Andrea Zauner, Walter Gruber, Roman Freunberger, Wolfgang KlimeschAbstract:In the present study we have tested the hypothesis that evoked traveling Alpha Waves are behaviorally significant. The results of a visual-semantic categorization task show that three early ERP components including the P1–N1 complex had a dominant frequency characteristic in the Alpha range and behaved like traveling Waves do. They exhibited a traveling direction from midline occipital to right lateral parietal sites. Phase analyses revealed that this traveling behavior of ERP components could be explained by phase-delays in the Alpha but not theta and beta frequency range. Most importantly, we found that the speed of the traveling Alpha Wave was significantly and negatively correlated with reaction time indicating that slow traveling speed was associated with fast picture-categorization. We conclude that evoked Alpha oscillations are functionally associated with early access to visual-semantic information and generate – or at least modulate – the early Waveforms of the visual ERP.
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pre stimulus Alpha phase alignment predicts p1 amplitude
Brain Research Bulletin, 2011Co-Authors: Robert Fellinger, Wolfgang Klimesch, Walter Gruber, Roman Freunberger, Michael DoppelmayrAbstract:Since years there is a hotly discussed dispute whether event-related potentials are either generated by an evoked component or by resetting of ongoing phase. We argue that phase-reset must not be proven in order to accept the general involvement of phase in ERP-generation as it is only one of several possible mechanisms influencing or generating certain ERP-components. Supporting data are presented showing that positive peaks of ongoing pre-stimulus Alpha activity are not randomly distributed in time across trials. Most importantly, we found that a certain kind of pre-stimulus phase concentration that represents a continuous development of an Alpha Wave up to the time window where the P1 is generated is associated with an enlarged event-related component. We conclude that ongoing oscillations cannot be considered random background noise (even before stimulus onset) and that there are probably more phase-mechanisms that can contribute to the ERP-generation.
Michael Doppelmayr - One of the best experts on this subject based on the ideXlab platform.
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pre stimulus Alpha phase alignment predicts p1 amplitude
Brain Research Bulletin, 2011Co-Authors: Robert Fellinger, Wolfgang Klimesch, Walter Gruber, Roman Freunberger, Michael DoppelmayrAbstract:Since years there is a hotly discussed dispute whether event-related potentials are either generated by an evoked component or by resetting of ongoing phase. We argue that phase-reset must not be proven in order to accept the general involvement of phase in ERP-generation as it is only one of several possible mechanisms influencing or generating certain ERP-components. Supporting data are presented showing that positive peaks of ongoing pre-stimulus Alpha activity are not randomly distributed in time across trials. Most importantly, we found that a certain kind of pre-stimulus phase concentration that represents a continuous development of an Alpha Wave up to the time window where the P1 is generated is associated with an enlarged event-related component. We conclude that ongoing oscillations cannot be considered random background noise (even before stimulus onset) and that there are probably more phase-mechanisms that can contribute to the ERP-generation.
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P1 and Traveling Alpha Waves: Evidence for Evoked Oscillations
Journal of neurophysiology, 2006Co-Authors: Wolfgang Klimesch, Simon Hanslmayr, Paul Sauseng, Walter Gruber, Michael DoppelmayrAbstract: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,...
Seiji Nishifuji - One of the best experts on this subject based on the ideXlab platform.
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EMBC - EEG recovery enhanced by acute aerobic exercise after performing mental task with listening to unpleasant sound
2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2011Co-Authors: Seiji NishifujiAbstract:The present paper investigated response of electroencephalogram (EEG) to aerobic exercise with low intensity after performing mental task with listening to acoustic stimuli in order to measure a recovery effect of the acute exercise on the EEG. The mean amplitude of the Alpha Wave (8–13 Hz) was significantly reduced during performing mental arithmetic and/or listening to 5 KHz unpleasant tone. In particular, the mean reduction rate of the amplitude was more than 20 % in the low-frequency range of the Alpha Wave (8–10Hz) under both stressors. On the other hand, the Alpha Wave was fixed after an acute exercise of 20 min; the mean amplitude of the Alpha Wave exceeded 30 % of spontaneous level prior to stressed conditions in the low-frequency range but unchanged in the high-frequency range. Response of the theta Wave was similar to the low-Alpha Wave, while beta and gamma Waves showed no significant change in response to the stressors and exercise. The observation indicates that the acute exercise with low intensity may be responsible for the rapid recovery and enhancement of the Alpha Wave in the low-frequency range and theta Wave.
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Effect of acoustic stimuli and mental task on Alpha, beta and gamma rhythms in brain Wave
Proceedings of SICE Annual Conference 2010, 2010Co-Authors: Seiji Nishifuji, Masahiro Sato, Daisuke Maino, Shogo TanakaAbstract:The paper examined response of brain Wave to mental task and acoustic stimuli in order to evaluate stress effects of mental work and acoustic environment on brain electrical activity. The amplitude of the Alpha Wave (8-13 Hz), which is the representative component of awake brain Wave, was decreased by approximately 15~20 % during performing the mental task (mental arithmetic and memorization) alone and listening to acoustic stimuli (5 KHz tone as unpleasant sound and a classical music, Pachelbel's Canon as a pleasant sound) alone in comparing to the amplitude of the spontaneous Alpha Wave at rest. Such amplitude suppression corresponds to increase of temporal phase fluctuation of the Alpha Wave by 15~30%. In particular, the reduction rate of the amplitude of the Alpha Wave in the low-frequency range was up to 25 % under the combined stresses, namely, the mental arithmetic and unpleasant 5 KHz tone. On the other hand, the amplitude of the beta and gamma Waves showed no significant change under most of stress conditions including combined stresses. The observation obtained indicates that the combination of acoustic and mental stresses considerably affects the stabilization of the Alpha Wave in the low frequency range which may be a crucial key to measure the mental stress using the brain Waves.
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Destabilization of Alpha Wave during and after listening to unpleasant and pleasant acoustic stimuli
2008 SICE Annual Conference, 2008Co-Authors: Seiji Nishifuji, I. MiyaharaAbstract:Spatiotemporal responses of brain Alpha Wave to unpleasant and pleasant acoustic stimuli are investigated in terms of the amplitude and phase of the Alpha Wave. The amplitude of the Alpha Wave is significantly reduced not only during listening to unpleasant acoustic stimuli but also after listening to the stimuli such as teeth gnashing and a single frequency tone with a frequency of 5 K Hz. Amplitude fluctuation is monotonically increased from the onset to 100 s after the offset of listening to the unpleasant stimuli. Such amplitude instability is also observed during listening to pleasant acoustic stimuli such as classical music and babble of a stream, but is not statistically significant after listening to the stimuli. Temporal phase change rate of the Alpha Wave is significantly increased during and after listening to the unpleasant acoustic stimuli, whereas it is not significantly changed for the pleasant music. The destabilization effect of the unpleasant stimuli on the Alpha Wave seems to remain for a longer period than that of the pleasant stimuli.
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spatiotemporal phase characteristics of brain Alpha Wave entrained to alternating red and blue flicker stimuli
Japanese Journal of Applied Physics, 2006Co-Authors: Seiji Nishifuji, H. Ohkado, Shogo TanakaAbstract:We investigate spatiotemporal phase characteristics of the brain Alpha Waves in the entrainment to red, blue and alternating red/blue flicker stimuli. The alternating red/blue stimuli induce two distinct phase relationships between the Alpha Waves over the scalp dependent on subjects: 1) an antiphase relationship in approximately half the subjects in which the phases of the Alpha Waves are in the state of antiphase between the occipital and frontal lobes and 2) an in-phase relationship for the remaining subjects in which the phases of the Alpha Waves over the entire scalp are almost identical with only small phase differences. In the in-phase relationship, there occurs a phase difference approximately 90 deg between the occipital Alpha Wave and the alternating red/blue flicker stimuli, whereas the phase difference becomes almost zero in the antiphase relationship. The former anomalous phase response at the occipital lobe triggers the in-phase relationship over the entire scalp.
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Characteristics of Alpha Wave response to flicker stimuli with color alternation
Electronics and Communications in Japan (Part III: Fundamental Electronic Science), 2005Co-Authors: Seiji Nishifuji, H. Ohkado, Shogo TanakaAbstract:Spatiotemporal responses of the Alpha Wave to flicker stimuli with temporal alternation of two stimulus colors are investigated and compared to the properties of the Alpha Wave at rest and in response to single-color stimuli in order to evaluate the effect of the alternation of stimulus colors on the electroencephalogram. The Alpha Wave can be entrained by all kinds of flicker stimuli, that is, the frequency of the Alpha Wave shifts to that of the stimuli. The spatial distributions of the amplitude and phase difference on presentation of alternating red/blue stimuli show anomalous spatial characteristics for more than half the subjects, namely, a large amplitude in the centro-parietal region and the same phase over the entire scalp, whereas those under other stimuli show large amplitude in the occipital and frontal regions and opposite phase in the frontal and occipital regions. The results may provide useful information for considering the effect of color alternation of flicker stimuli on the electroencephalogram, as well as for modeling the generating mechanism of Alpha Waves. They may also be useful for evaluating the effect of color alternation in photic stimuli, such as video images and animations, on the electroencephalogram. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 89(4): 1–10, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20204
