Department of Neurology

Posttraumatic stress disorder (PTSD) is known to be associated with altered medial prefrontal activation in response to threatening stimuli and with behavioural deficits in prefrontal functions such as working memory and attention. Given the importance of these areas and processes for decision-making, this functional magnetic resonance imaging study investigated whether decision-making is altered in patients with PTSD. In particular, the neural response to gain and loss feedback was evaluated in a decision-making task in which subjects could maximise their number of points total by learning a particular response pattern.

Independent component analysis (ICA) is one of the most valuable explorative methods for analyzing resting-state networks (RSNs) in fMRI, representing a data-driven approach that enables decomposition of high-dimensional data into discrete components. Extensions to a group-level suffer from the drawback of evaluating single-subject resting-state components of interest either using a predefined spatial template or via visual inspection. FENICA introduced in the context of group ICA methods is based solely on spatially consistency across subjects directly reflecting similar networks. Therefore, group data can be processed without further visual inspection of the single-subject components or the definition of a template .

Analogous to the evolution of biological sensor-systems, the progress in "medical sensor-systems", i.e., diagnostic procedures, is paradigmatically described. Outstanding highlights of this progress are magnetic resonance imaging (MRI) and spectroscopy (MRS), which enable non-invasive, in vivo acquisition of morphological, functional, and metabolic information from the human body with unsurpassed quality. Recent achievements in high and ultra-high field MR (at 3 and 7 Tesla) are described, and representative research applications in Medicine and Psychology in Austria are discussed. Finally, an overview of current and prospective research in multi-modal imaging, potential clinical applications, as well as current limitations and challenges is given.

Attribution theory plays a central role in understanding cognitive processes that have emotional consequences; however, there has been very limited attention to its neural basis. After reviewing classical studies in social psychology in which attribution has been experimentally manipulated we developed a new approach that allows the investigation of state attributions and emotional consequences using neuroscience methodologies. Participants responded to the Erikson Flanker Task, but, in order to maintain the participant's beliefs about the nature of the task and to produce a significant number of error responses, an adaptive algorithm tuned the available time to respond such that, dependent on the subject's current performance, the negative feedback rate was held at chance level. In order to initiate variation in attribution participants were informed that one and the same task was either easy or difficult. As a result of these two different instructions the two groups differed significantly in error attribution only on the locus of causality dimension. Additionally, attributions were found to be stable over a large number of trials, while accuracy and reaction time remained the same. Thus, the new paradigm is particularly suitable for cognitive neuroscience research that evaluates brain behaviour relationships of higher order processes in 'simulated achievement settings'.

Learning from the outcome of decisions can be expected not only to change future decisions, but also our reaction to future outcomes. Using functional magnetic resonance imaging we investigated the neural responses of healthy subjects to feedback about choice outcomes before and after learning a response strategy which led to correct choices only. The task was designed so that losses were unavoidable even when all the choices made were correct. Subjects showed a distinct pattern of learning starting with an initial exploratory phase in which hypotheses about the correct strategy were generated and tested, followed by a phase of rapid strategy acquisition before reaching a final phase of proficiency. Neural activation was more pronounced during feedback processing in the exploratory phase than in the proficiency phase in a distributed network encompassing prefrontal and parietal areas as well as the striatum. These areas are involved in working memory processes, the management of uncertainty and the establishment of stimulus-outcome contingencies. Reduced activation during feedback processing following learning was not only observed within subjects across learning phases, but also between subjects with different learning speeds. Thus, controlled and automatic processing are characterised by differing amounts of activation in identical taskrelevant areas. Furthermore, whereas the same brain regions coded for gains and losses, the activation following gains changed to a larger extent with learning than following losses. This suggests that positive prediction errors are more sensitive to increased reward predictability than are negative prediction errors.

Throughout recent years there has been an increasing interest in studying unconscious visual processes. Such conditions of unawareness are typically achieved by either a sufficient reduction of the stimulus presentation time or visual masking. However, there are growing concerns about the reliability of the presentation devices used. As all these devices show great variability in presentation parameters, the processing of visual stimuli becomes dependent on the display-device, e.g. minimal changes in the physical stimulus properties may have an enormous impact on stimulus processing by the sensory system and on the actual experience of the stimulus.

Die funktionelle Magnetresonanztomographie (fMRT) stellt zurzeit die wichtigste Methode zur nichtinvasiven Funktionslokalisation im Gehirn dar. Mit der Verfügbarkeit von MRT-Geräten mit Magnetfeldstärken von 4 Tesla (T) und darüber ergeben sich neue Möglichkeiten, mittels fMRT die neuronale Aktivität in bislang unerreichter Genauigkeit zu untersuchen. In diesem Artikel zeigen wir anhand mehrerer Studien bei 7 T, in wieweit die Zugewinne an Sensitivität und Spezifität verwendet werden können, um die bisherigen Grenzen der fMRT-Auflösung in räumlicher und zeitlicher Hinsicht auszuweiten. Die neuen Herausforderungen, die mit dem Schritt zu ultrahohen Magnetfeldern einhergehen, werden dabei ebenso diskutiert wie mögliche Ansätze zu deren Lösung. Functional magnetic resonance imaging (fMRI) is currently the primary method for non-invasive functional localization in the brain. With the emergence of MR systems with field strengths of 4 Tesla and above, neuronal activation may be studied with unprecedented accuracy. In this article we present different approaches to use the improved sensitivity and specificity for expanding current fMRT resolution limits in space and time based on several 7 Tesla studies. In addition to the challenges that arise with ultra-high magnetic fields possible solutions will be discussed.

demonstrated that subjects with low ability to solve a complex visuo-spatial imagery task show higher activity in occipital, parietal and frontal cortex during task processing than subjects with high ability. This finding has been interpreted in the sense of the so-called ''neural efficiency'' hypothesis, which assumes that the central nervous system of individuals with higher intellectual abilities is functioning in a more efficient way than the one of individuals with lower abilities. Using a higher spatial resolution of SCP recordings, and by employing the source localization method of LORETA (low-resolution electromagnetic tomography), we investigated this hypothesis by performing an extended replication of Vitouch et al.'s study. SCPs during processing of a visuo-spatial imagery task were recorded in pre-selected subjects with either high or low abilities in solving the imagery task. Topographic and LORETA analyses of SCPs revealed that a distributed network of extrastriate occipital, superior parietal, temporal, medial frontal and prefrontal areas was active during task solving. This network is well in line with former studies of the functional neuroanatomy of visuo-spatial imagery. Contrary to our expectations, however, the results of Vitouch et al. as well as of other studies supporting the neural efficiency hypothesis could not be confirmed since no difference in brain activity between groups was observed. This inconsistency between studies might be due to differing task processing strategies. While subjects with high abilities in the Vitouch et al. study seemed to use a visuo-perceptual task solving approach, all other subjects relied upon a visuo-motor task processing strategy. D 2005 Elsevier B.V. All rights reserved. Theme: Neural basis of behavior Topic: Cognition (C. Lamm). Cognitive Brain Research 25 (2005) 900 -912 www.elsevier.com/locate/cogbrainres C. Lamm et al. / Cognitive Brain Research 25 (2005) 900 -912 901

The present study was conducted to determine the functional neuroanatomical correlates of aesthetic experience using slow cortical potentials (SCPs). Thirty participants without any particular background in the fine arts were presented with various representational (semiabstract) and abstract paintings dating from the 20th and 21st century in two experimental conditions, i.e. with or without stylistic information. The paintings had to be rated by the participants in terms of understanding and aesthetic qualities. In order to identify the cortical structures involved, the SCPs were subjected to current density analysis using lowresolution electromagnetic tomography (LORETA). The comparison of representational and abstract paintings revealed significantly higher activation for representational artworks in several regions of the brain, predominantly in the left frontal lobe and bilaterally in the temporal lobes. According to the participants' reports, the representational artwork stimuli evoked more associations, accompanied by stronger activation of multimodal association areas in the temporal lobe. Furthermore, without stylistic information, the stimuli evoked stronger activation mainly in the left frontal and parietal lobes. Results also showed that stylistic information led to a better understanding of the paintings, but resulted in reduced cortical activation in the left hemisphere. This might have been due to less verbally oriented processing. These observations help explain the difficulties many beholders often have in appreciating abstract artworks. ava i l a b l e a t w w w. s c i e n c e d i r e c t . c o m w w w. e l s ev i e r. c o m / l o c a t e / b r a i n r e s ARTICLE IN PRESS Please cite this article as: Lengger, P.G., et al., Functional neuroanatomy of the perception of modern art: A DC-EEG study on the influence of stylistic information on aesthetic experience, Brain Res. (2007),

Functional imaging studies investigating perception of depth rely solely on one type of depth cue based on non-natural stimulus material. To overcome these limitations and to provide a more realistic and complete set of depth cues natural stereoscopic images were used in this study. Using slow cortical potentials and source localization we aimed to identify the neural correlates of monocular and binocular depth cues. This study conWrms and extends functional imaging studies, showing that natural images provide a good, reliable, and more realistic alternative to artiWcial stimuli, and demonstrates the possibility to separate the processing of diVerent depth cues.

Exploratory analysis of functional MRI data allows activation to be detected even if the time course differs from that which is expected. Independent Component Analysis (ICA) has emerged as a powerful approach, but current extensions to the analysis of group studies suffer from a number of drawbacks: they can be computationally demanding, results are dominated by technical and motion artefacts, and some methods require that time courses be the same for all subjects or that templates be defined to identify common components. We have developed a group ICA (gICA) method which is based on single-subject ICA decompositions and the assumption that the spatial distribution of signal changes in components which reflect activation is similar between subjects. This approach, which we have called Fully Exploratory Network Independent Component Analysis (FENICA), identifies group activation in two stages. ICA is performed on the single-subject level, then consistent components are identified via spatial correlation. Group activation maps are generated in a secondlevel GLM analysis. FENICA is applied to data from three studies employing a wide range of stimulus and presentation designs. These are an event-related motor task, a block-design cognition task and an event-related chemosensory experiment. In all cases, the group maps identified by FENICA as being the most consistent over subjects correspond to task activation. There is good agreement between FENICA results and regions identified in prior GLM-based studies. In the chemosensory task, additional regions are identified by FENICA and temporal concatenation ICA that we show is related to the stimulus, but exhibit a delayed response. FENICA is a fully exploratory method that allows activation to be identified without assumptions about temporal evolution, and isolates activation from other sources of signal fluctuation in fMRI. It has the advantage over other gICA methods that it is computationally undemanding, spotlights components relating to activation rather than artefacts, allows the use of familiar statistical thresholding through deployment of a higher level GLM analysis and can be applied to studies where the paradigm is different for all subjects.

Throughout recent years there has been an increasing interest in studying unconscious visual processes. Such conditions of unawareness are typically achieved by either a sufficient reduction of the stimulus presentation time or visual masking. However, there are growing concerns about the reliability of the presentation devices used. As all these devices show great variability in presentation parameters, the processing of visual stimuli becomes dependent on the display-device, e.g. minimal changes in the physical stimulus properties may have an enormous impact on stimulus processing by the sensory system and on the actual experience of the stimulus.

Throughout recent years there has been an increasing interest in studying unconscious visual processes. Such conditions of unawareness are typically achieved by either a sufficient reduction of the stimulus presentation time or visual masking. However, there are growing concerns about the reliability of the presentation devices used. As all these devices show great variability in presentation parameters, the processing of visual stimuli becomes dependent on the display-device, e.g. minimal changes in the physical stimulus properties may have an enormous impact on stimulus processing by the sensory system and on the actual experience of the stimulus.

Die funktionelle Magnetresonanztomographie (fMRT) stellt zurzeit die wichtigste Methode zur nichtinvasiven Funktionslokalisation im Gehirn dar. Mit der Verfügbarkeit von MRT-Geräten mit Magnetfeldstärken von 4 Tesla (T) und darüber ergeben sich neue Möglichkeiten, mittels fMRT die neuronale Aktivität in bislang unerreichter Genauigkeit zu untersuchen. In diesem Artikel zeigen wir anhand mehrerer Studien bei 7 T, in wieweit die Zugewinne an Sensitivität und Spezifität verwendet werden können, um die bisherigen Grenzen der fMRT-Auflösung in räumlicher und zeitlicher Hinsicht auszuweiten. Die neuen Herausforderungen, die mit dem Schritt zu ultrahohen Magnetfeldern einhergehen, werden dabei ebenso diskutiert wie mögliche Ansätze zu deren Lösung. Functional magnetic resonance imaging (fMRI) is currently the primary method for non-invasive functional localization in the brain. With the emergence of MR systems with field strengths of 4 Tesla and above, neuronal activation may be studied with unprecedented accuracy. In this article we present different approaches to use the improved sensitivity and specificity for expanding current fMRT resolution limits in space and time based on several 7 Tesla studies. In addition to the challenges that arise with ultra-high magnetic fields possible solutions will be discussed.

Processing and interpreting the face is generally very important because one is often required to make rapid decisions in life on the basis of meagre information. Ninety-two volunteers used a computer-assisted test battery to assess 40 profiles of patients (8 skeletal Class II and 8 skeletal Class III patients, each pre-and postoperatively, with 8 skeletal Class I photographs serving as controls). On a 7-point Likert scale the raters were asked to evaluate aesthetics and a few relevant personality traits (e.g. unintelligent, inhibited, aggressive, brutal). The photographs of the two patient groups were rated significantly less attractive and intelligent prior to surgery than the photographs of the control group. In respect of personality traits, the photographs of the skeletal Class III group differed more strongly from normal ones. In respect of aesthetics and intelligence, both patient groups benefited markedly from surgery. For some personality traits, significant interactions were found between the two groups on pre-post comparison. The method underlying the study is useful for evaluating the outcome of orthognathic surgery, but also indicates the strongly generalized and unconscious processes involved in the estimation of people's personality traits, especially when these concern deviations from the socially normal condition.