Stephan Lau

Technische Universität Ilmenau

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Jens Haueisen

Technische Universität Ilmenau

Roy F. Baumeister

Harvard University

Lars Flemming

Jena University Hospital

Mark Jenkinson

Wellcome Centre for Integrative Neuroimaging

Daniel Güllmar

Jena University Hospital

Anette Hiemisch

Universität Greifswald

Connie J. Clark

Duke University

Mark Cook

St Vincent's Hospital

Simon J. Vogrin

St Vincent's Hospital

Volker Röth

University of Basel

Cooperative Institutions

University of Zurich

University of Geneva

University Hospital of Geneva

Inserm

University of Adelaide

University of Bern

Ludwig-Maximilians-Universität München

Technische Universität Ilmenau

Centre National de la Recherche Scientifique

University Hospital of Bern

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Skull Defects in MEG and EEG: Experimental Results and Modelling

Biomedical Engineering / Biomedizinische Technik (2012)

Stephan Lau Daniel Güllmar Lars Flemming Jens Haueisen

10.1515/bmt-2012-4164

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FAST-IT:FindA SimpleTest —InTIA (transient ischaemic attack): a prospective cohort study to develop a multivariable prediction model for diagnosis of TIA through proteomic discovery and candidate lipid mass spectrometry, neuroimaging and machine learning—study protocol

BMJ Open (2022)

Austin G. Milton Stephan Lau Karlea L. Kremer Sushma R. Rao Emilie Mas

Introduction Transient ischaemic attack (TIA) may be a warning sign of stroke and difficult to differentiate from minor stroke and TIA-mimics. Urgent evaluation and diagnosis is important as treating TIA early can prevent subsequent strokes. Recent improvements in mass spectrometer technology allow quantification of hundreds of plasma proteins and lipids, yielding large datasets that would benefit from different approaches including machine learning. Using plasma protein, lipid and radiological biomarkers, our study will develop predictive algorithms to distinguish TIA from minor stroke (positive control) and TIA-mimics (negative control). Analysis including machine learning employs more sophisticated modelling, allowing non-linear interactions, adapting to datasets and enabling development of multiple specialised test-panels for identification and differentiation. Methods and analysis Patients attending the Emergency Department, Stroke Ward or TIA Clinic at the Royal Adelaide Hospital with TIA, minor stroke or TIA-like symptoms will be recruited consecutively by staff-alert for this prospective cohort study. Advanced neuroimaging will be performed for each participant, with images assessed independently by up to three expert neurologists. Venous blood samples will be collected within 48 hours of symptom onset. Plasma proteomic and lipid analysis will use advanced mass spectrometry (MS) techniques. Principal component analysis and hierarchical cluster analysis will be performed using MS software. Output files will be analysed for relative biomarker quantitative differences between the three groups. Differences will be assessed by linear regression, one-way analysis of variance, Kruskal-Wallis H-test, χ 2 test or Fisher’s exact test. Machine learning methods will also be applied including deep learning using neural networks. Ethics and dissemination Patients will provide written informed consent to participate in this grant-funded study. The Central Adelaide Local Health Network Human Research Ethics Committee approved this study (HREC/18/CALHN/384; R20180618). Findings will be disseminated through peer-reviewed publication and conferences; data will be managed according to our Data Management Plan (DMP2020-00062).

Ischaemic stroke

Stroke

10.1136/bmjopen-2020-045908

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Publisher Correction: Perception thresholds and qualitative perceptions for electrocutaneous stimulation

Scientific Reports (2022)

Eva‐Maria Dölker Stephan Lau Maria Anne Bernhard Jens Haueisen

The confidence intervals of the median relative attention thresholds A a show:A a, 20 µs > A a, 50 µs > A a, 100 µs > A a, 150 µs > A a, 200 µs = A a, 250 µs > A a, 500 µs > A a, 1000 µs > A a, 2000 µs . The confidence intervals of the median relative intolerance thresholds A i show:A i, 20 µs > A i, 50 µs > A i, 100 µs > A i, 150 µs = A i, 200 µs = A i, 250 µs > A i, 500 µs > A i, 1000 µs = A i, 2000 µs .Table 2 shows the results of linear regression y = β 0 + β 1 • x with the auxiliary variable for the pulse width x = 1/t p .

10.1038/s41598-022-14650-8

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Influence of volume conductor modeling on source reconstruction in magnetoencephalography and electroencephalography

Jens Haueisen Stephan Lau Lars Flemming Hermann Sonntag Burkhard Maeß

The function and structure of the human brain is immensely complex and, at the same time, the key to understanding human behavior and many of today's prevailing diseases. In most cases, this system cannot be investigated directly, but only non-invasively from outside the head. Although several non-invasive measurement modalities are available, only magnetoencephalography (MEG) and electroencephalography (EEG) provide information with a high temporal resolution. In order to reconstruct the neuronal activity underlying measured EEG and MEG data both the forward problem (computing the electromagnetic field due to given sources) and the inverse problem (finding the best fitting sources to explain given data) have to be solved. The forward problem involves a source model and a model with the conductivities of the head. The conductivity model can be as simple as a homogeneously conducting sphere or as complex as a finite element model consisting of millions of elements, each with a different anisotropic conductivity tensor. The question is addressed how complex the employed forward model should be, and, more specifically, the influence of anisotropic volume conduction and the influence of conductivity inhomogeneities are evaluated. For this purpose high resolution finite element models of the rabbit and the human head are employed in combination with individual conductivity tensors to quantify the influence of white matter anisotropy on the solution of the forward and inverse problem in EEG and MEG. Although the current state of the art in the analysis of this influence of brain tissue anisotropy on source reconstruction does not yet allow a final conclusion, the results available indicate that the expected average source localization error due to anisotropic white matter conductivity might be within the principal accuracy limits of current inverse procedures. However, in some percent of the cases a considerably larger localization error might occur. In contrast, dipole orientation and dipole strength estimation are influenced significantly by anisotropy [1]. Skull conductivity inhomogeneities such as the spongy bone structure embedded in the compact bone [2] or surgical holes or fontanels in infants have a non-negligible effect on the EEG and MEG forward and inverse problem solution. Especially when source positions are expected to be in the vicinity of the conductivity inhomogeneity and when a large difference with respect to the skull conductivity is indicated, the modeling approach should take the inhomogeneities into account [3]. In conclusion, models taking into account tissue anisotropy and conductivity inhomogeneities information are expected to improve source estimation procedures. Depending on the question addressed, the complexity of the forward and inverse solution approach has to be chosen.

Magnetoencephalography

Human head

10.1109/ursigass.2014.6930127

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Nonlinear interactions of high-frequency oscillations in the human somatosensory system

Clinical Neurophysiology (2008)

U. Jaros Bernd Hilgenfeld Stephan Lau Gabriel Curio Jens Haueisen

10.1016/j.clinph.2008.08.011

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The Function of Positive Affect During Goal-Attainment: Is Affect a Mediator of Self-Regulative Behavior in the Face of Competing Goals?

SSRN Electronic Journal (2013)

Stephan Lau Anette Hiemisch

Two experiments investigated the links between feedback about goal progress, positive affect and task-switching in the face of competing goals. Several models predict that the willingness to shift resources to a competing goal will be higher if the progress in the focal goal is good. Moreover, Carver (2003) proposes that these shifts represent an increase in openness to other goals that is mediated by positive affect, which is triggered by good progress. Both predictions were tested using explicit progress-feedback that permitted the induction of affect during goal attainment and the measurement of subsequent effects on goal-directed behavior. While the results generally endorse the predictions about resource shifting, they contradict the assumption that the behavioral differences are mediated by affect. Therefore, if explicit feedback about goal progress is present, positive affect contains no relevant information and does not mediate changes in goal-directed behavior that occur due to feedback.

Affect

Mediator

Goal Orientation

10.2139/ssrn.2222721

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Evidence for the Context Dependence of the Side-Effect Effect

Journal of Cognition and Culture (2016)

Stephan Lau Rainer Reisenzein

In four experiments involving 565 German speakers we tested several hypotheses about possible determinants of the side-effect effect ( see ), which consists of judging foreseen bad, but not good, side-effects of actions as intentionally produced. Experiment 1 failed to find intentionality ascriptions for bad side-effects for the majority of the participants in two different scenarios and obtained no consistent support for two hypothesized social-cognitive determinants of the see , the agent’s attitude and the mode of effect description. Experiment 2 replicated the see in the original ceo scenario, but again found no evidence that the effect was influenced by the agent’s attitude towards the side-effect. The see was also not influenced by a manipulation of the moral quality of the agent’s primary goal. Experiment 3 investigated six additional scenarios used in previous studies and again obtained clear evidence for the see only in the ceo scenario. In addition, Experiment 3 demonstrated that judgments of both intent and intentionality strongly increased if the original side-effect was described as a means to the agent’s primary goal, or as an independently pursued goal. Taken together, the findings suggest that for German speakers, the see depends on the specifics of the scenario content and is difficult to obtain outside the original ceo scenario. Consistent with these conclusions, Experiment 4 documented parallel difficulties replicating the “means effect”, an analogue of the see on the level of means, but replicated the see in a scenario closely modeled after the original ceo scenario.

Intentionality

Experimental philosophy

10.1163/15685373-12342180

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What About Her? Increasing the Actionability of HUMINT in Paternalistic Cultures by Considering Female Intelligence

International Journal of Intelligence and CounterIntelligence (2022)

Stephan Lau Farina T. S. Bauer

Female intelligence refers to a gender-sensitive perspective in collection planning that not only recognizes women as targets of collection but also considers females as operatives. These considerations become especially relevant in paternalistic cultural contexts, such as Afghanistan. Potential obstacles (e.g., myths) for female intelligence as well as past attempts at implementation (e.g., female engagement teams) are reviewed, before four areas of concern are identified that must be addressed in the future. The analysis is expanded by presenting survey and interview data from a sample of Bundeswehr operatives with human intelligence experience in paternalistic countries. We suggest how to address existing concerns and increase the actionability of field human intelligence units by incorporating females as valuable assets on both sides of the military intelligence collection process.

Paternalism

10.1080/08850607.2022.2068890

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Optimal Magnetic Sensor Vests for Cardiac Source Imaging

Sensors (2016)

Stephan Lau Bojana Petković Jens Haueisen

Magnetocardiography (MCG) non-invasively provides functional information about the heart. New room-temperature magnetic field sensors, specifically magnetoresistive and optically pumped magnetometers, have reached sensitivities in the ultra-low range of cardiac fields while allowing for free placement around the human torso. Our aim is to optimize positions and orientations of such magnetic sensors in a vest-like arrangement for robust reconstruction of the electric current distributions in the heart. We optimized a set of 32 sensors on the surface of a torso model with respect to a 13-dipole cardiac source model under noise-free conditions. The reconstruction robustness was estimated by the condition of the lead field matrix. Optimization improved the condition of the lead field matrix by approximately two orders of magnitude compared to a regular array at the front of the torso. Optimized setups exhibited distributions of sensors over the whole torso with denser sampling above the heart at the front and back of the torso. Sensors close to the heart were arranged predominantly tangential to the body surface. The optimized sensor setup could facilitate the definition of a standard for sensor placement in MCG and the development of a wearable MCG vest for clinical diagnostics.

Torso

Magnetocardiography

Robustness

Biomagnetism

10.3390/s16060754

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High temporal resolution EEG in EEG-fMRI investigation of epileptiform brain activity

Ghent University Academic Bibliography (Ghent University) (2015)

Simon J. Vogrin Stephan Lau Mark Cook

EEG-fMRI

Brain mapping

Source

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