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
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
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
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
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
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
em.Univ.Prof.Dr. Hellmuth Petsche