稽古轩主的博客

Center for Brain Research Medical University of Vienna

Center for Brain Research
Medical University of Vienna / Spitalgasse 4, A-1090 Vienna, Austria

稽古轩主按：维也纳大学医学院的脑研究中心的有关语言处理过程中EEG研究相干，参阅下列资料，并深入阅读这里发表的有关论文。更详细资料参加http://www.univie.ac.at/cognitiveneuroscience/ （The Cognitive Neuroscience Group ； The professional sphere of activity of the Cognitive Neuroscience Group essentially concerns cognitive information processing in the brain and analysis of neurophysiological signals (EEG). ）
 

Rappelsberger, P., Weiss, S. & Schack, B. (2000). Coherence and phase relations between EEG traces recorded from different locations. In: R. Miller (Ed.). Time and the Brain. Conceptual Advances in Brain Research Series. Harwood Academic Publishers, pp. 297-330.

---

Summary:

This contribution deals with EEG coherence and phase analyses using two different techniques. First, Fourier transform was applied to compute cross spectra between pairs of electrode signals of EEG trials of constant length. The cross spectra of a number of trials were averaged yielding coherence and phase spectra representing the mean properties within the length of the trials, usually 1 or 2 seconds. Second, an adaptive autoregressive-moving-average (ARMA) model was used to compute instantaneous coherence and phase values with a time resolution in the Millisecond range.

In the first experiment EEG was recorded during auditory presentation of concrete and abstract nouns. 19 right-handed female native German speakers participated. The main coherence results using the Fourier approach relate to the Alpha1 band (8-10 Hz) and the Beta1 band (13-18 Hz). In the Alpha1 band both word classes revealed about the same changes during word processing suggesting that this band reflects processes common to both word classes. In contrast, in the Beta1 band clear differences were found. These differences mainly concern the involvement of visual and frontal association areas probably due to visual images evoked by the concrete nouns.

The second experiment was conducted with 25 right-handed females. Concrete and abstract nouns were presented auditorily but also visually. The main coherence results using the Fourier approach revealed that the Alpha1 band is sensitive to the modality of stimulus presentation but does not distinguish between the memorisation of abstract and concrete nouns. In contrast, stimulus modality independent coherence differences were found in the Delta, Theta and Beta1 bands.

Measurement of time relations, i.e. studies of the direction of information transfer, was made using both, the Fourier approach for time intervals and the ARMA approach at time instants during the memorisation of nouns. Due to the highly dynamic process with changing directions of information transfer the Fourier approach based on 1 s trials after stimulus onset yielded only very coarse estimations of the time relations during word processing. The short lasting properties during word processing were smeared and to a great extend extinguished. In single subject studies, the ARMA approach clearly demonstrated an occipital-frontal information transfer in the Beta1 band for the visual stimulus presentation. During auditory stimulus presentation temporal sites tended to lead occipital sites but there was also a trend of occipital sites to lead central and left frontal sites.

  

 

Selected Readings of Prof. Weiss and Rappelsberger

---

Sabine Weiss

• Weiss, S., Müller, H.M., Schack, B., King, J.W., Kutas, M., Rappelsberger, P. (2005). Increased neuronal synchronization accompanying sentence comprehension. International Journal of Psychophysiology 57: 129-141.
• Schack, B. & Weiss, S. (2005). Quantification of phase synchronization phenomena and their importance for verbal memory processes. Biological Cybernetics 92: 275-287.
• Hemmelmann, C., Horn, M., Süsse, T., Vollandt, R. & Weiss, S. (2004). Multiple Tests for the evaluation of high-dimensional EEG data during memory encoding. Journal of Neuroscience Methods 142: 209-217..
• Hemmelmann, C., Horn, M., Reiterer, S., Schack, B., Süsse, T. & Weiss, S. (2004). Multivariate tests for the evaluation of high-dimensional EEG data. Journal of Neuroscience Methods 139: 111-120.
• Meinicke, P. , Hermann, T., Bekel, H., Müller, H.M., Weiss, S. & Ritter, H. (2004). Identification of Discriminative Features in the EEG. Journal of Intelligent Data Analysis 8: 97-107.
• Schack, B. & Weiss, S. (2003). Phase synchronization - A mechanism for neural integration for event-related potentials. Biomedizinische Technik 48 (1): 150-153.
• Schack, B. & Weiss, S. (2003). Event-related phase coupling phenomena during verbal memory encoding. Brain Topography 15, p.201. 
• Schack, B., Weiss, S. & Rappelsberger, P. (2003). Cerebral information transfer during word processing: Where and when does it occur and how fast is it? Human Brain Mapping 19: 18-36.
• Weiss, S. & Müller, H.M. (2003). The contribution of EEG coherence to the investigation of language. Brain and Language 85: 325-343.
• Weiss, S. & Müller, H.M. (2003). Neuronal synchronization accompanying memory processing. Commentary on Ruchkin, D., Grafman, J., Cameron, K., Berndt, R.S.: "Working memory retention systems: A state of activated long-term memory". Behavioral Brain Sciences 26: 759-760.
• Weiss, S. & Schack, B. (2003). Transient networks of information transfer during the processing of concrete and abstract nouns. In: F. Schmalhofer, R.M. Young & G. Katz, Proceedings of "The European Cognitive Science Conference 2003". Laurence Erlbaum Associates, pp. 361-366.
• Hermann, T., Meinicke, P., Bekel, H., Ritter, H., Müller, H., & Weiss, S. (2002). Sonification for EEG data analysis. In: Proc. of the 8th Int. Conf. on auditory display .Int. Community for Auditory Display. Kyoto, Japan,  pp. 37-41.
• Schack, B., Rappelsberger, P., Vath, N., Weiss, S., Möller,E., Grießbach, G & Witte, H. (2001). EEG frequency and phase coupling during human information processing. Methods of Information in Medicine, 40: 106-111.
• Weiss, S., Müller, H.M., King, J.W., Kutas, M. & Rappelsberger, P. (2001). EEG-coherence analysis of naturally spoken English relative clauses. Brain Topography 13: 317.
• Schack, B., Rappelsberger, P., Anders, C., Weiss, S. & Möller, E. (2000). Quantification of synchronization processes by coherence and phase and its application in analysis of electrophysiological signals. International Journal of Bifurcation and Chaos, 10: 2565-2586.
• Weiss, S. & Rappelsberger, P (2000). Long-range EEG synchronization during word encoding correlates with successful memory performance. Cognitive Brain Research 9: 299-312.
• Weiss, S., Müller, H.M. & Rappelsberger P. (2000). Theta synchronisation predicts efficient memory encoding of concrete and abstract nouns. NeuroReport 11: 2357-2361.
• Rappelsberger, P., Weiss, S. & Schack, B. (2000). Coherence and phase relations between EEG traces recorded from different locations. In: R. Miller (Ed.). Time and the Brain, Conceptual Advances in Brain Research Series. Harwood Academic Publishers, pp. 297-330.
• Schack, B., Rappelsberger, P., Weiss, S. & Möller, E. (1999). Adaptive phase estimation and its application in EEG analysis of word processing. Journal of Neuroscience Methods 93: 49-59.
• Weiss, S., Müller, H.M. & Rappelsberger P. (1999). Processing concepts and scenarios: Electrophysiological findings on language representation. In: A. Riegler, M.Peschl & Stein, A.v. (Eds.). Understanding representation in cognitive sciences. New York: Plenum Press, pp. 237-245.
• Weiss, S. & Rappelsberger P. (1998). Left frontal EEG coherence reflects modality independent language processes. Brain Topography 11: 33-42.
• Weiss, S. & Rappelsberger P. (1997). Modality specific and semantic processes during language comprehension are reflected within different frequency bands: A topographic EEG coherence study. Biomedizinische Technik 42: 174-177.
• Schack, B. Weiss, S. & Rappelsberger, P. (1996). Dynamic topographic methods of coherence analysis of cognitive processes. Medical & Biological Engineering & Computing 34: 207-208.
• Weiss, S. & Rappelsberger P. (1996). EEG coherences within the 13-18 Hz band as correlates of a distinct lexical organization of concrete and abstract nouns in humans. Neuroscience Letters 209: 17-20.

 

Peter Rappelsberger

• Schack, B., Weiss, S. & Rappelsberger, P. (2003). Cerebral information transfer during word processing: Where and when does it occur and how fast is it? Human Brain Mapping 19, 18-36.
• Weiss, S., Müller, H.M., King, J.W., Kutas, M., Schack, B., Rappelsberger, P. (2002). Theta and beta synchronization reflect different processes during language comprehension. International Journal of Psychophysiology 45 : 45.
• Schack, B., Rappelsberger, P., Vath, N., Weiss, S., Möller,E., Grießbach, G & Witte, H. (2001). EEG frequency and phase coupling during human information processing. Methods of Information in Medicine, 40:106-111.
• Weiss, S., Müller, H.M., King, J.W., Kutas, M. & Rappelsberger, P. (2001). EEG-coherence analysis of naturally spoken English relative clauses. Brain Topography 13: 317.
• Rappelsberger P. (2000) . EEG coherence analysis: a method to visualise functional connections. In B.Saletu, F.Krijzer, G.Ferber, O.Anderer (Eds.): Electrophysiological Brain Research in Preclinical and clinical Pharmacology and Related Fields - An Update: Facultas Universitätsverlag Wien, pp 33-44. 
• Schack, B., Rappelsberger, P., Anders, C., Weiss, S. & Möller, E. (2000). Quantification of synchronization processes by coherence and phase and its application in analysis of electrophysiological signals. International Journal of Bifurcation and Chaos, 10: 2565-2586. 
• Rappelsberger, P., Schack, B., Weiss, S. & Möller, E. (2000). Instantaneous EEG coherence and phase analysis during word processing. Österreichische Gesellschaft für Artificial Intelligence-Journal 19: 16-21. 
• Weiss, S. & Rappelsberger, P (2000). Long-range EEG synchronization during word encoding correlates with successful memory performance. Cognitive Brain Research 9: 299-312. 
• Weiss, S., Müller, H.M. & Rappelsberger P. (2000). Theta synchronisation predicts efficient memory encoding of concrete and abstract nouns. NeuroReport, 11: 2357-2361. 
• Rappelsberger, P., Weiss, S. & Schack, B. (2000). Coherence and phase relations between EEG traces recorded from different locations. In: R. Miller (Ed.). Time and the Brain, Conceptual Advances in Brain Research Series. Harwood Academic Publishers, pp. 297-330. 
• Schack, B, Rappelsberger, P., Weiss, S., & Möller, E. (2000). EEG phase and frequency coupling during word processing. Brain Topography, 12: 294. 
• Rappelsberger, P., Weiss, S. & Schack, B. (2000). Coherence and phase relations between EEG traces recorded from different locations. In: R. Miller (Ed.). Time and the Brain, Conceptual Advances in Brain Research Series. Harwood Academic Publishers, pp. 297-330. 
• Schack, B, Rappelsberger, P., Weiss, S., & Möller, E. (2000). EEG phase and frequency coupling during word processing. Brain Topography, 12: 294.

Research Program

---

"Functional Cortical Networks during Language Comprehension"

Sabine Weiss

Hertha Firnberg Project T127, supported by the Austrian Science Foundation (FWF).

Main purpose of this project is the examination of the neuronal basis of language processing at the word and sentence level. Electric brain activity (EEG) shall be recorded during different language comprehension tasks and spectral analysis shall be applied. Particular emphasis is laid on the investigation of properties and meaning of coherence patterns within special frequency bands of the EEG. Previous results showed that coherence accompanying language processing considerably changes with respect to the frequency bands investigated. Coherence is a frequency-domain measure of similarity between EEG signals and reflects the degree of functional cooperation between neuronal substrates underlying the generation of those signals. In the light of current neurobiological theories knowledge about cortical synchronisation and information transfer is necessary for an adequate characterisation of cognitive brain functioning. The chosen methods for spectral analysis of the data are Fourier transform and the application of an adaptive fit of bivariate autoregressive moving average (ARMA) models which complement the data obtained by Fourier transform due to improved time and frequency resolution. In close cooperation with Bärbel Schack (University of Jena, Gemany) and Horst M. Müller (University of Bielefeld, Germany) an adaptive fit of bivariate autoregressive moving average (ARMA) models shall be applied to the data in order to obtain improved temporal and frequency resolution.

Beside basic research on the relation between brain function, cognition and language processing the results of these experiments can be applied in different fields of Medicine, Linguistics and Cognitive Science. As an example results can be applied to the treatment of disturbed language acquisition in children (L1) and to the improvement of second language acquisition (L2). Furthermore, aphasic syndromes may be better understood and therapy may be improved. Moreover, findings on language comprehension can be used for implementation in artificial communicators by members of the SFB 360 "Situierte künstliche Kommunikatoren" (University of Bielefeld).

Start: August 2001
End: February 2006

 

"A New Standard for Integrating Polygraphic Sleep Recordings into a Comprehensive Model of Human Sleep and Its Validation in Sleep Disorders."

Peter Rappelsberger

This is part of the SIESTA - BIOMED 2 shared cost project of the European Commission - Biomed-2 PL962040. The project was conducted by Univ.Doz.Dipl.Ing.Dr.G.Dorffner , Austrian Research Institute for Artificial Intelligence. This project aimed at extensive novel research on the architecture of nocturnal human sleep, as well as the development and evaluation of advanced methods for sleep analysis, based on polygraphic measurements, most prominently electrocencephalography (EEG). The main need for a novel standard of modeling sleep comes from the limits of the only widely accepted standard -- a sleep manual according to Rechtschaffen & Kales -- and the increasing dissatisfaction with it among clinicians.

Start: September 1997
End: 2001
Continuation by a private company www.thesiestagroup.com
Brief Overview

 

"Synchronisation and Timerelation between Cortical Regions during Memory Processes."

Werner Chromecek

The aim of my study is to explore the electrophysiological processes during the encoding and memorisation of digits and numbers. Main emphasis is laid on the time dependence and time course of the processes within and between different cortical regions. Furthermore, differences between good and poor memory performers are investigated. Participants were selected according to the results of a sub-test taken from an established intelligence-test due to good and poor memory. EEG of 18 female participants was recorded while they had to memorize digits and numbers. Stimuli were presented in four blocks and had to be recalled immediately after presentation.
In the Delta band subjects with good memory show higher coherence between frontal and parietal leads than subjects with poor memory. Furthermore, subjects show less higher coherence in the fourth trial than in the first trial. This difference is bigger in the group of bad performers than in the group of good performers. Since coherence may be considered as a measure for functional relationships between different cortical regions, the results may be interpreted that good performers seem to find an "ideal neuronal strategy". Moreover, they find this within shorter time than poor performers.

End: February 2006

 

" EEG-Coherence Analysis of Emotional Processing"

Julia Waldmüller

Recent studies have demonstrated that during the presentation of emotional stimuli (regardless of various induction methods) cortical areas are activated specifically (Davidson, 1995; Morris et al. 1998). These studies used different analysis methods to investigate the location of emotional processing. The aim of this study is to explore emotional processing using validated picture stimuli and word material analysed by EEG-coherence using FFT and ARMA (AutoRegressive-Moving-Average) techniques. These methods are used to investigate functionally connected cortical areas during emotional processing that constitute the basis of a dynamic emotion model/theory.

The EEG of 20 subjects is recorded during the presentation of both affective and emotionally neutral slides and words. Each subject is tested on a structural and an emotion-focussed processing task. Subjects' attention is directed either to a structural feature (estimating the number of people or letters) of the stimulus or to an emotional content of the stimulus. An expected effect could be that there are differences in cortical activity patterns due to presentation of emotional and non-emotional stimuli during the emotional task. It is also expected that there are differences in cortical activity patterns due to presentation of emotional and non-emotional stimuli when subjects' attention is directed to the structural feature (estimating).

End: February 2006

 

"Electrophysiological Correlates in Complex Mental Processes: An EEG and Coherence Study."

Birgit Alexe

The experimental material is a test (TEKODE, 1997), designed to evoke "complexity of thinking" during the performance of a task, which demands distinctive cognitive abilities, such as verbal, spatial, formal-logical and creative thinking. It is assumed that these different properties have to be integrated in a complex manner for the successful mastery of the performance.

The positive outcome underlying these complex thinking processes will be studied by EEG-coherence-analysis (international electrode 10-20 system). The experimental plan includes males and females of specialised professions, 18 cases in total. Most emphasis is put on how interactions between different brain areas take place and whether there are relationships with respect to the personality. Apart from this we are interested in recognizing eventual general cognitive operating strategies during information processing. We hope that the results will shed some light on human problem-solving abilities.

End: February 2006

 

"Electrophysiological Correlates of visual categorization."

Herwig Kopp

Recent work (diploma) involves research with EEG concerning visual categorization by the means of coherent brain activity and philosophical implications triggered by this experiment - as well vice versa - old philosophical questions which can be reexamined by the method of experimental science: Why do we recognize a cow as a cow and not as a chair?

End: February 2006

发布于10月26日 19:14 | 评论数(0) 阅读数(827)