Publications

{Indoor operation of unmanned aerial vehicles (UAVs) poses many challenges due to the lack of GPS signal and cramped spaces. The presence of obstacles in an unfamiliar environment requires reliable state estimation and active algorithms to prevent collisions. In this paper, we present a teleoperated quadrotor UAV platform equipped with an on-board miniature computer and a minimal set of sensors for this task. The platform is capable of highly accurate state-estimation, tracking of desired velocity commanded by the user and ensuring collision-free navigation. The robot estimates its linear velocity through a Kalman filter integration of inertial and optical flow (OF) readings with corresponding distance measurements. An RGB-D camera serves the purpose of providing visual feedback to the operator and depth measurements to build a probabilistic, robo-centric obstacle model, allowing the robot to avoid collisions. The platform is thoroughly validated in experiments in an obstacle rich environment.}

{Viewpoint selection has been an emerging area in computer graphics for some years, and it is now getting maturity with applications in fields such as scene navigation, scientific visualization, object recognition, mesh simplification, and camera placement. In this survey, we review and compare twenty-two measures to select good views of a polygonal 3D model, classify them using an extension of the categories defined by Secord et al., and evaluate them against the Dutagaci et al. benchmark. Eleven of these measures have not been reviewed in previous surveys. Three out of the five short-listed best viewpoint measures are directly related to information. We also present in which fields the different viewpoint measures have been applied. Finally, we provide a publicly available framework where all the viewpoint selection measures are implemented and can be compared against each other.}

{PURPOSE: To compare several different optimization algorithms currently used for localized in vivo B0 shimming, and to introduce a novel, fast, and robust constrained regularized algorithm (ConsTru) for this purpose. METHODS: Ten different optimization algorithms (including samples from both generic and dedicated least-squares solvers, and a novel constrained regularized inversion method) were implemented and compared for shimming in five different shimming volumes on 66 in vivo data sets from both 7 T and 9.4 T. The best algorithm was chosen to perform single-voxel spectroscopy at 9.4 T in the frontal cortex of the brain on 10 volunteers. RESULTS: The results of the performance tests proved that the shimming algorithm is prone to unstable solutions if it depends on the value of a starting point, and is not regularized to handle ill-conditioned problems. The ConsTru algorithm proved to be the most robust, fast, and efficient algorithm among all of the chosen algorithms. It enabled acquisition of spectra of reproducible high quality in the frontal cortex at 9.4 T. CONCLUSIONS: For localized in vivo B0 shimming, the use of a dedicated linear least-squares solver instead of a generic nonlinear one is highly recommended. Among all of the linear solvers, the constrained regularized method (ConsTru) was found to be both fast and most robust.}

{Traditional models of systems memory consolidation postulate two interacting memory stores, with rapid encoding of new information supported by the hippocampus and a gradually developing, stable storage in neocortical circuits. Recently, the posterior parietal cortex (PPC), particularly the precuneus, has been proposed as a cardinal location of neocortical long-term memory. We have shown functional activity in this area over repeated learning that is memory specific, long-term stable and related to memory accuracy. To conclusively identify the PPC as a location of memory storage, learningcontingent, lasting structural changes have to be demonstrated as well. Here, we used diffusion MRI to assess changes in brain microstructure, which reject neuronal plasticity. 41 participants learned object-place associations over 8 learning-recall repetitions in two sessions. Task-related activity was tracked with fMRI. Structural changes were assessed with dMRI at three time points (before, 90 minutes and 13 h after learning). A non-learning condition measured at the same times was employed as control. Functional PPC activity increases with learning repetitions, remains stable over a 13-h period and strongly correlates with recall performance. Furthermore, decreases in mean diffusivity indicate structural changes in the same area, which also develop after learning, remain stable for over 12 hours and correlate with behavioral performance. We thus show functional and structural changes in the PPC that fulfill all requirements for a neocortical long-term memory representation: learning specificity, long-term stability and behavioral relevance. The confirmation of structural plasticity in particular proves the importance of the PPC as a site of neocortical memory storage.}

{Our visual system\textquotesingles ability to group visual elements into meaningful entities and to separate them from others is referred to as scene segmentation. Visual motion often provides a powerful cue for this process as parallax or coherence can inform the visual system about scene or object structure. Here we tested the hypothesis that scene segmentation by motion cues relies on a common neural substrate in the parietal cortex. We used fMRI and a set of three entirely distinct motion stimuli to examine scene segmentation in the human brain. The stimuli covered a wide range of high-level processes, including perceptual grouping, transparent motion and depth perception. All stimuli were perceptually bistable such that percepts alternated every few seconds while the physical stimulation remained constant. The perceptual states were asymmetric, in that one reflected the default (non-segmented) interpretation, and the other the non-default (segmented) interpretation. We confirmed behaviorally that upon stimulus presentation, the default percept was always perceived first, before perceptual alternations ensued. Imaging results showed that across all stimulus classes perceptual scene-segmentation was associated with an increase of activity in the posterior parietal cortex together with a decrease of neural signal in the early visual cortex. This pattern of activation is compatible with predictive coding models of visual perception, and suggests that parietal cortex hosts a generic mechanism for scene segmentation.}

{Distractions are often viewed as a negative occurrence in the study of human factors. Nonetheless, the ability to disengage and redirect our attention to an unexpected event is vital to our survival. It allows us to detect possible threats or more rewarding goals. In my talk, I will speak on the event-related potential (ERP; distraction potential) that is involuntarily generated by the appearance of a complex sound in our environment, even when the sound bears no relevance to the task at hand and does not require an explicit response. I will expand on the characteristic waveform of the distraction potential and the factors that influence it. More importantly, I will propose how the distraction potential could be exploited towards understanding the task demands, particularly of manipulating closed-loop control systems (e.g., vehicles). Environment sounds can represent events of interest even if it is not apparent how or why they are task-relevant. In the context of driving, this could be a crying child in the backseat or a non-descript engine squeak. Even if a behavioral response is not required, the brain involuntarily responds, giving rise to a characteristic ERP waveform that has been termed the distraction potential (Escera \& Corral, 2003). Like the ERPs produced by task-relevant pure tones, namely those that participants are explicitly instructed to monitor and discriminate for, distraction potentials of task-irrelevant environment sounds depict an early negative deflection (cf., N1), followed by a late positive deflection (cf., P300). Unlike a typical auditory ERP, the late positive deflection of a distraction potential typically consists of two distinct positive deflections where a single P300 would typically be. The two P3 components (namely the early and late novelty P3 components) of a distraction potential are sensitive to the demands of an ongoing task, even though the environment sounds that generate them do not require a response. Indeed, observers are explicitly instructed to ignore these sounds. We have shown that visuo-motor steering demands attenuate the amplitudes of the early and late novelty P3 components of this distraction potential (Scheer, B\"ulthoff, Chuang, 2016). In contrast, the P300s generated by pure tones are sensitive to steering demands only if participants are instructed to discriminate target tones from distractor tones within a dual-task paradigm (Wickens, Kramer, Vanasse, \& Donchin, 1983). This means that task-irrelevant environment sounds can be used as probes for evaluating the demands of a visuo-motor steering task, without necessitating a secondary auditory discrimination task that could interact with and modify the demands of steering itself. Nonetheless, the question remains: Which of the two P3 components of a distraction potential are likely to be comparable to the well-established P300 generated to task-relevant pure tones? Two reasons lead us to believe that the late novelty P3 generated by task-irrelevant environment sounds is likely to resemble the P300 generated by task-relevant pure tones. First, we recently reported that instructing participants to pay attention to the auditory channel selectively increased the late novelty P3, but not the early novelty P3 component, of the distraction potential (Scheer, B\"ulthoff, Chuang, 2018). Thus, the late novelty P3 reflects the strategic allocation of attentional resources to a relevant modality regardless of the stimulus\textquoteright task relevance. Second, varying the complexity of the visuo-motor task\textquoterights control dynamics selectively attenuates only the late novelty P3 component of the distraction potential, whilst having no effect on the early novelty P3 (Scheer \& Chuang, under review). Other manipulations of steering difficulty, such as control disturbances, do not have a similar impact. These findings mirror those found in dual-task paradigms whereby similar conflicts were found on the P300 potentials generated by infrequent task-relevant tones (Wickens et al., 1983). Thus, we have proposed that the late novelty P3 component generated by complex and task-irrelevant sounds is comparable to the better established P300 potentials. Visuo-motor steering exerts a cross-modal decrement to auditory ERPs when it demands more executive working memory resources. This can be indexed either by the P300 of a task-relevant pure tone target or the late novelty P3 of a task-irrelevant environment sound. Operationally, this could give rise to the phenomenon of \textquotedblleftinattentional deafness\textquotedblright, whereby highly trained pilots fail to recognize unexpected yet highly critical sounds (i.e., warning of landing gear failure; . Using the late novelty P3 component allows us to evaluate ongoing task demands without disrupting the task that is under investigation by introducing a secondary task. This offers researchers the opportunity of inobtrusively evaluating what is broadly referred to as the \textquotedblleftcognitive workload\textquotedblright of more complex tasks, from playing Tetris (Miller, Rietschel, McDonald, \& Hatfield, 2011) to flight control (Jacquess et al., 2017).}

{Many forms of transport evoke symptoms of motion sickness (MS) in susceptible passengers. Symptoms include stomach awareness, palor, headache, sweating dizziness and nausea, and are caused by particular vehicle motions. The aim of this review is to summarize the literature on the relationship between motion characteristics and motion sickness. For example, which types of motions are most provocative, what is the effect of motion frequency and amplitude, and how can we predict whether a certain motion will be provocative. This review was carried out within the framework of the CORINNE project, which investigates the relationship between vibration characteristics in helicopters and the discomfort they cause on the passengers. The ISO 2631-11 proposes a method of predicting motion sickness incidence from a given motion profile, but only takes into account the vertical motion. It is to be expected that the prediction will not be optimal for helicopter trajectories, as motions in other degrees of freedom may also contribute. One of the project aims, therefore is to verify whether the current ISO method is valid, or whether it can be improved by taking motion in multiple degrees of freedom into account. In the following, we will first summarize the prediction method proposed in ISO 2631-1 and then summarize available literature on the effects of motions in other degrees of freedom. This review can then guide further research for the specific case of helicopter flight.}

{In this work, a true experimental comparison between a very high order spherical harmonic based shim setup and a multi-coil shim array is presented. Each technique has its own cons and pros which are studied through several often-used sequences. All evaluations are performed by shimming of the human brain at 9.4T.}

{This study compares APT-CEST between pre- and post-gadolinium in patients with gliomas at 3T, and evaluates the feasibility of performing CEST after administration of T1 contrast. The results of the study demonstrate that Gd administration does not significantly affect the quality of the APT-CEST image, encouraging the acquisition of CEST data, even after the administration of T1 contrast agents.}

{Major depressive disorder (MDD) is often accompanied by severe impairments in working memory (WM). Neuroimaging studies investigating the mechanisms underlying these impairments have produced conflicting results. It remains unclear whether MDD patients show hyper- or hypoactivity in WM-related brain regions and how potential aberrations in WM processing may contribute to the characteristic dysregulation of cognition\textendashemotion interactions implicated in the maintenance of the disorder. In order to shed light on these questions and to overcome limitations of previous studies, we applied a multivoxel pattern classification approach to investigate brain activity in large samples of MDD patients (N \textequals 57) and matched healthy controls (N \textequals 61) during a WM task that incorporated positive, negative, and neutral stimuli. Results showed that patients can be distinguished from healthy controls with good classification accuracy based on functional activation patterns. ROI analyses based on the classification weight maps showed that during WM, patients had higher activity in the left DLPFC and the dorsal ACC. Furthermore, regions of the default-mode network (DMN) were less deactivated in patients. As no performance differences were observed, we conclude that patients required more effort, indexed by more activity in WM-related regions, to successfully perform the task. This increased effort might be related to difficulties in suppressing task-irrelevant information reflected by reduced deactivation of regions within the DMN. Effects were most pronounced for negative and neutral stimuli, thus pointing toward important implications of aberrations in WM processes in cognition\textendashemotion interactions in MDD.}

{For the first time, we present a systematic framework to assess the intrinsic SNR performance of loop-only and dipole-only receive arrays in a realistic human head model. Thereby, we distribute generic current patterns on a helmet-like and a cylindrical coil holder. These current patterns form a basis set for any kind of receive element one could place on the holder. We demonstrate how to design an ideal receive array for human head applications by using complementary current patterns.}

{A hallmark of human social behavior is the effortless ability to relate one\textquotesingles own actions to that of the interaction partner, e.g. when stretching out one\textquotesingles arms to catch a tripping child. What are the behavioral properties of the neural substrates that support this indispensable human skill? Here we examined the processes underlying the ability to relate actions to each other, namely the recognition of spatio-temporal contingencies between actions (e.g. a \textquotesinglegiving\textquotesingle that is followed by a \textquotesingletaking\textquotesingle). We used a behavioral adaptation paradigm to examine the response properties of perceptual mechanisms at a behavioral level. In contrast to the common view that action sensitive units are primarily selective for one action (i.e. primary action, e.g. \textquotesinglethrowing\textquotesingle), we demonstrate that these processes also exhibit sensitivity to a matching contingent action (e.g. \textquotesinglecatching\textquotesingle). Control experiments demonstrate that the sensitivity of action recognition processes to contingent actions cannot be explained by lower-level visual features or amodal semantic adaptation. Moreover, we show that action recognition processes are only sensitive to contingent actions, but not to non-contingent actions, demonstrating their selective sensitivity to contingent actions. Our findings provide first evidence for the selective coding mechanism of action contingencies by action-sensitive processes and demonstrate how the representations of individual actions in social interactions can be linked in a unified representation.}

{Recent advances in MR technology have enabled increased spatial resolution for routine functional and anatomical imaging, which has created demand for software tools that are able to process these data. The availability of high-resolution data also raises the question of whether higher resolution leads to substantial gains in accuracy of quantitative morphometric neuroimaging procedures, in particular the cortical surface reconstruction and cortical thickness estimation. In this study we adapted the FreeSurfer cortical surface reconstruction pipeline to process structural data at native submillimeter resolution. We then quantified the differences in surface placement between meshes generated from (0.75 mm)3 isotropic resolution data acquired in 39 volunteers and the same data downsampled to the conventional 1 mm3 voxel size. We find that when processed at native resolution, cortex is estimated to be thinner in most areas, but thicker around the Cingulate and the Calcarine sulci as well as in the posterior bank of the Central sulcus. Thickness differences are driven by two kinds of effects. First, the gray\textendashwhite surface is found closer to the white matter, especially in cortical areas with high myelin content, and thus low contrast, such as the Calcarine and the Central sulci, causing local increases in thickness estimates. Second, the gray\textendashCSF surface is placed more interiorly, especially in the deep sulci, contributing to local decreases in thickness estimates. We suggest that both effects are due to reduced partial volume effects at higher spatial resolution. Submillimeter voxel sizes can therefore provide improved accuracy for measuring cortical thickness.}

{Alcohol consumption affects many organs and tissues, including skeletal muscle. However, the molecular mechanism of ethanol action on skeletal muscle remains unclear. Here, using molecular dynamics simulations and single channel recordings, we show that ethanol interacts with a negatively charged amino acid within an extracellular region of the neuromuscular nicotinic acetylcholine receptor (nAChR), thereby altering its global conformation and reducing the single channel current amplitude. Charge reversal of the negatively charged amino acid abolishes the nAChR-ethanol interaction. Moreover, using transgenic animals harboring the charge-reversal mutation, ex vivo measurements of muscle force production show that ethanol counters fatigue in wild type but not homozygous $\alpha$E83K mutant animals. In accord, in vivo studies of motor coordination following ethanol administration reveal an approximately twofold improvement for wild type compared to homozygous mutant animals. Together, the converging results from molecular to animal studies suggest that ethanol counters muscle fatigue through its interaction with neuromuscular nAChRs.}

{Previous research suggests that reasoning about imagined perspectives within immersive environments is difficult. In two experiments we examined the alignment effects (i.e., poor performance as the difference between one\textquoterights actual and imagined perspective increases) when the observer is external to the scene. Participants adopted imagined perspectives around a table and pointed to the position of a target. In Experiment 1 the spatial scene was experienced either as immediate in immersive virtual reality (VR) with participants located within the scene or as remote presented on a virtual screen within VR. In Experiment 2 participants viewed the scene on a screen in real world. Results showed that the size of the alignment effect was similar across environments in Experiment 1, suggesting that viewing the scene as immediate or remote does not create additional conflicts in perspective taking. However, when the scene was presented in the real world (Experiment 2) the alignment effect was smaller compared to viewing the scene remotely in VR (Experiment 1). Although one would expect that immersive scenes would yield a strong alignment effect, in fact having visual access to body information which by default is lacking in VR, might be an important factor for perspective taking.}

{Background The purpose of this work was to investigate noninvasive early detection of treatment response of breast cancer patients to neoadjuvant chemotherapy (NAC) using chemical exchange saturation transfer (CEST) measurements sensitive to amide proton transfer (APT) at 7 T. Methods CEST images were acquired in 10 tumors of nine breast cancer patients treated with NAC. APT signals in the tumor, before and after the first cycle of NAC, were quantified using a three-pool Lorentzian fit of the z-spectra in the region of interest. The changes in APT were subsequently related to pathological response after surgery defined by the Miller-Payne system. Results Significant differences (P \textless  0.05, unpaired Mann-Whitney test) were found in the APT signal before and after the first cycle of NAC in six out of 10 lesions, of which two showed a pathological complete response. Of the remaining four lesions, one showed a pathological complete response. No significant difference in changes of APT signal were found between the different pathological responses to NAC treatment (P \textgreater 0.05, Kruskal-Wallis test). Conclusions This preliminary study shows the feasibility of using APT CEST magnetic resonance imaging as a noninvasive biomarker to assess the effect of NAC in an early stage of NAC treatment of breast cancer patients.}

{Neoadjuvant chemotherapy (NAC) has an important role in the treatment of breast cancer and the need for early detection of treatment response is high. Therefore we investigated the feasibility of using APT CEST at 7T as a biomarker for this purpose. Ten lesions were included and APT signal before and after the first cycle of NAC were correlated to the pathological response. Significant differences were found in APT signal corresponding with the pathological response. These results suggest that APT CEST may be used to predict the response to NAC treatment in an early stage.}

{Functional Magnetic Resonance Imaging (fMRI) is a powerful tool for neuroscience. It allows the visualization of active areas in the human brain. Combining this method with haptic interfaces allows one to conduct human motor control studies with an opportunity for standardized experimental conditions. However, only a small number of specialized MR-compatible haptic interfaces exists that were mostly built around specific research questions. The devices are designed for pure translational, rotational or grasping movements. In this work, we present a novel MR-compatible haptic interface with seven DoF which allows for both translations and rotations in three DoF each, as well as a two-finger precision grasp. The presented haptic interface is the first one with these capabilities and is designed as a universal tool for human motor control studies involving fMRI. It allows for the switching of the paradigm to reprogramming rather than redesigning when moving on to a new research question. We introduce its kinematics and control, along with results of MR compatibility tests and a preliminary fMRI study, showing the applicability of the device.}

{Recent work indicates that the central nervous system assesses the causality of visual and inertial information in the estimation of qualitative characteristics of self-motion and spatial orientation, and forms multisensory perceptions in accordance with the outcome of these assessments. Here, we extend the assessment of this Causal Inference (CI) strategy to the quantitative domain of traveled distance. We present a formal model of how stimuli result in sensory estimates, how percepts are constructed from sensory estimates, and how responses result from percepts. Starting with this formalization, we derived probabilistic formulations of CI and competing models for perception of traveled distance. In an experiment, participants (n\textequals9) were seated in the Max Planck Cablerobot Simulator, and shown a photo-realistic virtual rendering of the simulator hall via a Head-Mounted Display. Using this setup, the participants were presented with various unisensory and (incongruent) multisensory visual-inertial horizontal linear surge motions, differing only in amplitude (i.e., traveled distance). Participants performed both a Magnitude Estimation and a Two-Interval Forced Choice task. Overall, model comparisons favor the CI model, but individual analysis shows a Cue Capture strategy is preferred in most individual cases. Parameter estimates indicate that visual and inertial sensory estimates follow a Stevens\textquoteright power law with positive exponent, and that noise increases with physical distance in accordance with a Weber\textquoterights law. Responses were found to be biased towards the mean stimulus distance, consistent with an interaction between percepts and prior knowledge in the formulation of responses. Magnitude estimate data further showed a regression to the mean effect. The experimental data did not provide unambiguous support for the CI model. However, model derivations and fit results demonstrate it can reproduce empirical findings, arguing in favor of the CI model. Moreover, the methods outlined in the present study demonstrate how different sources of distortion in responses may be disentangled by combining psychophysical tasks.}

{Functional MRI (fMRI) benefits from both increased sensitivity and specificity with increasing magnetic field strength, making it a key application for Ultra-High Field (UHF) MRI scanners. Most UHF-fMRI studies utilize the dramatic increases in sensitivity and specificity to acquire high-resolution data reaching sub-millimeter scales, which enable new classes of experiments to probe the functional organization of the human brain. This review article surveys advanced data analysis strategies developed for high-resolution fMRI at UHF. These include strategies designed to mitigate distortion and artifacts associated with higher fields in ways that attempt to preserve spatial resolution of the fMRI data, as well as recently introduced analysis techniques that are enabled by these extremely high-resolution data. Particular focus is placed on anatomically-informed analyses, including cortical surface-based analysis, which are powerful techniques that can guide each step of the analysis from preprocessing to statistical analysis to interpretation and visualization. New intracortical analysis techniques for laminar and columnar fMRI are also reviewed and discussed. Prospects for single-subject individualized analyses are also presented and discussed. Altogether, there are both specific challenges and opportunities presented by UHF-fMRI, and the use of proper analysis strategies can help these valuable data reach their full potential.}

{Dynamic CEST studies such as dynamic glucose enhanced imaging, have gained a lot of attention recently, as it monitors the uptake and wash-out of glucose shown in tumor models in animals (1,2) and patients with glioblastoma (3,4). The expected CEST effects after injection are rather small in tissue especially at clinical field strengths (1-2 \textpercent). Small movements during the dynamic CEST measurement together with a subtraction-based evaluation can lead to pseudo CEST effects of the same order of magnitude. These artifacts are studied herein.}

{Body image disturbance (BID) is a core symptom of anorexia nervosa (AN), but as yet distinctive features of BID are unknown. The present study aimed at disentangling perceptual and attitudinal components of BID in AN. We investigated n \textequals 24 women with AN and n \textequals 24 controls. Based on a three-dimensional (3D) body scan, we created realistic virtual 3D bodies (avatars) for each participant that were varied through a range of $\pm$20 of the participants\textquoteright weights. Avatars were presented in a virtual reality mirror scenario. Using different psychophysical tasks, participants identified and adjusted their actual and their desired body weight. To test for general perceptual biases in estimating body weight, a second experiment investigated perception of weight and shape matched avatars with another identity. Women with AN and controls underestimated their weight, with a trend that women with AN underestimated more. The average desired body of controls had normal weight while the average desired weight of women with AN corresponded to extreme AN (DSM-5). Correlation analyses revealed that desired body weight, but not accuracy of weight estimation, was associated with eating disorder symptoms. In the second experiment, both groups estimated accurately while the most attractive body was similar to Experiment 1. Our results contradict the widespread assumption that patients with AN overestimate their body weight due to visual distortions. Rather, they illustrate that BID might be driven by distorted attitudes with regard to the desired body. Clinical interventions should aim at helping patients with AN to change their desired weight.}

{Background Early identification of prognostic superior characteristics in glioma patients such as Isocitrate dehydrogenase(IDH)-mutation and O6-methylguanine-DNA-methyltransferase (MGMT) promotor methylation status is of great clinical importance. The study purpose was to investigate the non-invasive predictability of IDH-mutation status, MGMT promotor methylation, and differentiation of lower versus higher grade glioma (LGG vs. HGG) in newly-diagnosed patients employing relaxation-compensated multi-pool Chemical Exchange Saturation Transfer (CEST) magnetic resonance imaging (MRI) at 7.0 Tesla (7T). Methods Thirty-one newly-diagnosed glioma patients were included in this prospective study. CEST MRI was performed at a 7T whole-body scanner. Nuclear Overhauser Effect (NOE) and isolated amide proton transfer (APT, downfield NOE-suppressed APT\textequalsdns-APT) CEST signals (mean value and 90th signal percentile) were quantitatively investigated in the whole tumor area with regard to predictability of IDH-mutation, MGMT promotor methylation status, and differentiation of LGG vs. HGG. Statistics were performed using receiver operating characteristic (ROC) and area under the curve (AUC) analysis. Results were compared to advanced MRI methods (apparent diffusion coefficient (ADC) and relative cerebral blood volume (rCBV) ROC/AUC analysis) obtained at 3T. Results dns-APT CEST contrasts yielded highest AUCs in IDH-mutation status prediction (dns-APTmean\textequals91.84, p\textless0.01; dns-APT90\textequals97.96, p\textless0.001). Furthermore, dns-APT metrics enabled significant differentiation of LGG vs. HGG (AUC: dns-APTmean\textequals0.78, p\textless0.05; dns-APT90\textequals0.83, p\textless0.05). There was no significant difference regarding MGMT promotor methylation status at any contrast (p\textgreater0.05). Conclusions Relaxation-compensated multi-pool CEST MRI, particularly dns-APT imaging, enabled prediction of IDH-mutation status and differentiation of LGG vs. HGG and should therefore be considered as non-invasive MR biomarker in the diagnostic workup.}

{A Bayesian fitting algorithm was combined with analytical approximations of the Bloch-McConnell (BM) equations with the aim to considerably reduce processing time. The accuracy of the algorithm was assessed with simulated data and data from phantom experiments and compared to fit results obtained with the numerical solution of the BM equations. Continuous-wave and pulsed saturation was considered. The results showed agreement between estimates and ground truth as well as between the approximate analytical and numerical model implementations of the Bayesian algorithm. A considerable reduction of processing time was achieved.}

{Objective This study investigates the neural basis of inattentional deafness, which could result from task irrelevance in the auditory modality. Background Humans can fail to respond to auditory alarms under high workload situations. This failure, termed inattentional deafness, is often attributed to high workload in the visual modality, which reduces one\textquoterights capacity for information processing. Besides this, our capacity for processing auditory information could also be selectively diminished if there is no obvious task relevance in the auditory channel. This could be another contributing factor given the rarity of auditory warnings. Method Forty-eight participants performed a visuomotor tracking task while auditory stimuli were presented: a frequent pure tone, an infrequent pure tone, and infrequent environmental sounds. Participants were required either to respond to the presentation of the infrequent pure tone (auditory task-relevant) or not (auditory task-irrelevant). We recorded and compared the event-related potentials (ERPs) that were generated by environmental sounds, which were always task-irrelevant for both groups. These ERPs served as an index for our participants\textquoteright awareness of the task-irrelevant auditory scene. Results Manipulation of auditory task relevance influenced the brain\textquoterights response to task-irrelevant environmental sounds. Specifically, the late novelty-P3 to irrelevant environmental sounds, which underlies working memory updating, was found to be selectively enhanced by auditory task relevance independent of visuomotor workload. Conclusion Task irrelevance in the auditory modality selectively reduces our brain\textquoterights responses to unexpected and irrelevant sounds regardless of visuomotor workload.}

{An exhaustible supply of mental resources necessitate that we are selective for what we attend to. Attention prioritizes what ought to be processed and what ignored, allocating valuable resources to selected information at the cost of unattended information elsewhere. For this purpose it is necessary to know the conditions that help the brain decide when attention should be paid, where to and to what information. This dissertation shows how auditory cues can support the management of limited attentional resources based on auditory characteristics. Auditory cues can increase the overall alertness, orient attention to unattended information, or manage attentional resources by informing of an upcoming task-switch and, therefore, indicate when to pay attention to which task.}

{Purpose Phase artifacts due to B0 inhomogeneity can severely degrade the quality of MR images. The artifacts are particularly prominent in long-TE scans and usually appear as ghosting and blur. We propose a retrospective phase correction method based on autofocusing. The proposed method uses raw data acquired with standard imaging sequences, and does not rely on navigators or external measures of field inhomogeneity. Methods We formulate and solve the optimization problem, where we seek the latent phase offsets that are associated with an optimal value of the image quality measure that is evaluated in the spatial domain. As a quality measure we use entropy computed on spatial image gradients. We propose two types of objective function, both compatible with parallel imaging and accelerated image acquisition. Results We evaluate the method on both synthetic and real data. In real data case we evaluate the performance on a range of sequences and images acquired with different acceleration factors. The experimental results demonstrate that our method is capable of minimizing ghosting artifacts and that the quality of the output images is similar to navigator-based reconstructions. Conclusion The presented technique can be alternative to or complement navigator-based methods, and is able to improve images with severe phase artifacts from all standard imaging sequences.}

{Many psychological experiments require human participants for which researchers often need to share the same equipment (computers, fMRI scanners, etc.). As a result recruitment of participants is a time consuming task that requires coordination between researchers. Here we present a new free online tool for participant recruitment called Banto that manages participant recruitment and equipment booking. Banto was partially developed with the help of the Department of Perception, Cognition and Action at the Max Planck Institute of Biological Cybernetics, T\"ubingen, Germany. Banto works like an online posting board: experimenters post their experiments and participants sign up for them. Once a participant signs up for an experiment appointment, all equipment that experimenters specified as necessary for the experiment (e.g. computers, rooms) is automatically booked along. While Banto is free to use we ask users to support the project by claiming some overhead costs for participant recruitment in future grant applications.}

{Attention deficit and hyperactivity disorder (ADHD) is a prevalent childhood disorder that is often maintained throughout the development and persists into adulthood. Established etiology models suggest that deficient inhibition underlies the core ADHD symptoms. While experimental evidence for impaired motor inhibition is overwhelming, little is known about the sensory inhibition processes, their changes throughout the development, and the relationship to ADHD symptoms. Here, we used the well-established binocular rivalry (BR) paradigm to investigate for the very first time the inhibitory processes related to visual perception in adults with ADHD. In BR, perception alternates between two dichoptically presented images throughout the viewing period, with shorter dominant percept durations and longer transition periods indicating poorer suppression/inhibition. Healthy controls (N \textequals 28) and patients with ADHD (N \textequals 32) were presented with two dissimilar images (orthogonal gratings) separately to each eye through a mirror stereoscope and asked to report their perceptual experiences. There were no differences between groups in any of the BR markers. However, an association between transition durations and symptom severity emerged in the ADHD group. Importantly, an exploratory multiple regression analysis revealed that inattention symptoms were the sole predictor for the duration of transition periods. The lack of impairments to sensory inhibition in adult, but not pediatric ADHD may reflect compensatory changes associated with development, while a correlation between inhibition and inattention symptoms may reveal an invariant core of the disorder.}

{Singh proposes a cultural evolutionary theory of shamanic practices, including trance. We argue that cultural factors are deeply intertwined with biological aspects in shaping shamanic practices, and the underlying biology is critical. We discuss the neural underpinnings of rhythm-induced trance, how they can facilitate insight, and how altered states can promote healing.}

{Previous literature suggests that a disturbed ability to accurately identify own body size may contribute to overweight. Here, we investigated the influence of personal body size, indexed by body mass index (BMI), on body size estimation in a non-clinical population of females varying in BMI. We attempted to disentangle general biases in body size estimates and attitudinal influences by manipulating whether participants believed the body stimuli (personalized avatars with realistic weight variations) represented their own body or that of another person. Our results show that the accuracy of own body size estimation is predicted by personal BMI, such that participants with lower BMI underestimated their body size and participants with higher BMI overestimated their body size. Further, participants with higher BMI were less likely to notice the same percentage of weight gain than participants with lower BMI. Importantly, these results were only apparent when participants were judging a virtual body that was their own identity (Experiment 1), but not when they estimated the size of a body with another identity and the same underlying body shape (Experiment 2a). The different influences of BMI on accuracy of body size estimation and sensitivity to weight change for self and other identity suggests that effects of BMI on visual body size estimation are self-specific and not generalizable to other bodies.}

{A growing number of studies investigated anisotropies in representations of horizontal and vertical spaces. In humans, compelling evidence for such anisotropies exists for representations of multi-floor buildings. In contrast, evidence regarding open spaces is indecisive. Our study aimed at further enhancing the understanding of horizontal and vertical spatial representations in open spaces utilizing a simple traveled distance estimation paradigm. Blindfolded participants were moved along various directions in the sagittal plane. Subsequently, participants passively reproduced the traveled distance from memory. Participants performed this task in an upright and in a 30\mbox{$^\circ$} backward-pitch orientation. The accuracy of distance estimates in the upright orientation showed a horizontal\textendashvertical anisotropy, with higher accuracy along the horizontal axis compared with the vertical axis. The backward-pitch orientation enabled us to investigate whether this anisotropy was body or earth-centered. The accuracy patterns of the upright condition were positively correlated with the body-relative (not the earth-relative) coordinate mapping of the backward-pitch condition, suggesting a body-centered anisotropy. Overall, this is consistent with findings on motion perception. It suggests that the distance estimation sub-process of path integration is subject to horizontal\textendashvertical anisotropy. Based on the previous studies that showed isotropy in open spaces, we speculate that real physical self-movements or categorical versus isometric encoding are crucial factors for (an)isotropies in spatial representations.}

{Alzheimer\textquotesingles disease (AD) is the most common cause for cognitive dysfunction at high age. In AD, pathological hallmarks such as beta-amyloid (A\ss) aggregation and also neurometabolic change, as indicated by altered myo-inositol (mI) and N-acetylaspartate (NAA) levels, typically precede manifestation of cognitive dysfunction by years. While cerebrovascular disease occurs at earliest stages of AD pathogenesis, the interplay between vascular and neurometabolic brain change is largely unknown. Thirty cognitively normal elderly persons (age\textequals70$\pm$5.6 years, MMSE\textequals29.2$\pm$1) received 11-C-Pittsburgh Compound B PET for estimating A\ss-plaque density, 7 Tesla (7T) fluid-attenuated inversion recovery MRI for quantifying white matter hyperintensity volume, and high-resolution FIDLOVS-based magnetic resonance spectroscopic imaging (MRSI) at 7T to investigate tissue-specific neurometabolism in the posterior cingulate and precuneus (PCP). Beta-amyloid (\ss\textequals0.45, p\textequals0.018) and white matter hyperintensities (\ss\textequals0.40, p\textequals0.046) were independently and interactively (\ss\textequals -0.49, p\textequals0.026) associated with a higher ratio of mI over NAA (mI/NAA) in PCP gray matter but not in white matter. Our data suggest that cerebrovascular disease and A\ss burden are synergistically related to AD-related gray matter neurometabolism at high age.}

{Network bursting is the most common type of spontaneous activity of dissociated neuronal cultures [1,2]. The frequency, length, amplitude, and shape of bursts vary substantially depending on the culture preparation, age, environment, and cellular composition [3]. Most of the models proposed to explain network bursting explicitly included components that drive bursting behavior, such as feedback, adaptation, or synaptic fatigue [4,5,6,7]. However, it is not clear whether such specific components are a necessary prerequisite of bursting activity. In the current study, we show that bursting occurs as one of the spontaneous dynamical states of a sparse random network of excitatory and inhibitory leaky Integrate-and-fire neurons with delta synapses. This type of network models is one of the most simple candidates to study the behavior of dissociated neuronal cultures. Yet, previously described synchronous states of such network models are not reconcilable with experimental observations [8]. These states have a relatively high frequency of global oscillations or show only a small amount of network synchrony. We investigated the behavior of the model outside of the typically studied parameter-intervals and found that population bursting appears in networks with strong synapses and very slow external Poisson input. In this specific region of the parameters space, the system shows slow bistable dynamics. The network spontaneously fluctuates between almost quiescent asynchronous state and fast synchronous firing. This transition closely resembles the network bursting in neuronal cultures. Our model displays a variety of burst\textquoterights shapes, amplitudes, and frequencies, some of which exhibit a clear parameter dependence. For instance, we demonstrate that the frequency of bursts depends on the coupling strength and relative strength of inhibitory synapses. Finally, we show that this type of dynamics is preserved in networks of different sizes when the synaptic strength is scaled proportionally 1K$\surd$. Overall, our model suggests that the sparse random network of excitatory and inhibitory neurons can exhibit various types of network bursting activity on the mesoscopic level. This concept can further extend mechanistic understanding of the variability of bursting dynamics in living neuronal cultures.}

{The perceptual upright is thought to be constructed by the central nervous system (CNS) as a vector sum; by combining estimates on the upright provided by the visual system and the body\textquoterights inertial sensors with prior knowledge that upright is usually above the head. Recent findings furthermore show that the weighting of the respective sensory signals is proportional to their reliability, consistent with a Bayesian interpretation of a vector sum (Forced Fusion, FF). However, violations of FF have also been reported, suggesting that the CNS may rely on a single sensory system (Cue Capture, CC), or choose to process sensory signals based on inferred signal causality (Causal Inference, CI). We developed a novel alternative-reality system to manipulate visual and physical tilt independently. We tasked participants (n \textequals 36) to indicate the perceived upright for various (in-)congruent combinations of visual-inertial stimuli, and compared models based on their agreement with the data. The results favor the CI model over FF, although this effect became unambiguous only for large discrepancies ($\pm$60\mbox{$^\circ$}). We conclude that the notion of a vector sum does not provide a comprehensive explanation of the perception of the upright, and that CI offers a better alternative.}

{In order to determine the T1 relaxation times of the metabolites in human brain including the ones that have either shorter T2 relaxation times or represent J-coupled spin systems, shorter TE times have to be chosen where there is a significant macromolecular contribution. Therefore, the behaviour of macromolecules (MMs) and their relaxation have to be understood clearly. In [1] the T1 relaxation time of the macromolecular baseline has been determined as a whole using single inversion recovery but values have not been provided for individual MMs, in [2] it has been estimated for the MM peak at 0.93 ppm. Here we attempt to understand the T1 relaxation pattern for the individual macromolecules at 9.4T in the human brain with a double inversion recovery (DIR) technique in order to measure the relaxation of individual MM components which relax at different rates and uniquely impact the overlying metabolite spectrum in traditional excitation approaches.}

{Pavlovian influences are important in guiding decision-making across health and psychopathology. There is an increasing interest in using concise computational tasks to parametrise such influences in large populations, and especially to track their evolution during development and changes in mental health. However, the developmental course of Pavlovian influences is uncertain, a problem compounded by the unclear psychometric properties of the relevant measurements. We assessed Pavlovian influences in a longitudinal sample using a well characterised and widely used Go-NoGo task. We hypothesized that the strength of Pavlovian influences and other \textquoteleftpsychomarkers\textquoteright guiding decision-making would behave like traits. As reliance on Pavlovian influence is not as profitable as precise instrumental decision-making in this Go-NoGo task, we expected this influence to decrease with higher IQ and age. Additionally, we hypothesized it would correlate with expressions of psychopathology. We found that Pavlovian effects had weak temporal stability, while model-fit was more stable. In terms of external validity, Pavlovian effects decreased with increasing IQ and experience within the task, in line with normative expectations. However, Pavlovian effects were poorly correlated with age or psychopathology. Thus, although this computational construct did correlate with important aspects of development, it does not meet conventional requirements for tracking individual development. We suggest measures that might improve psychometric properties of task-derived Pavlovian measures for future studies.}

{Studies of anatomical and functional connectivity lay down a basis for our understanding of the brain networks [1]. On a macroscale the measures are based on the coarse observations that allow capturing major connection tracts in the brain. However, on mesoscale and microscale, derivation of the networks\textquoteright connectivity have to rely on observation form a tiny fraction of the system. The inference of the whole network properties thus has to be done by extrapolation from the observed set to an unobserved one [2]. Our primary goal here is to understand how to make this inference rigorously. Network science\textquoteright tools describe relevant network properties, but so far it is not known how the subsampling alters them. One of centrally used observables to characterize brain network is a small-worldness index: an average clustering coefficient divided by a diameter of the network. In a set of different network classes (random, small-word, scale-free) we demonstrate analytically and numerically that the average local clustering coefficient is preserved by subsampling (Figure A). Therefore changes in the small-worldness under subsampling is driven by changes in the inferred diameter. We observe that the diameter is strongly influenced by the subsampling thus our inference of small-worldness without correction for the sample size is biased. As next step, we are aiming at finding regularities in diameter changes under subsampling. The brain networks have a highly complex structure, that is not captured by the simple random networks we consider in theoretical studies. To account for it, we investigate functional networks extracted from the developed cultures using High-Density Multi-Electrode Array (HD-MEA). We pre-process the recordings using SpiCoDyn package [3] and employ transfer entropy (TE) as a measure capturing information flow [4]. We define functional connectivity by conventional thresholding the TE matrix at the level of one standard deviation above the mean. We consider different window-subsampling of the full HD-MEA (Figure B). The threshold for significant functional connections depends on the sampled set (Figure C). Thus the network inferred from the subsampling of the whole system differs from the subnetwork with the same nodes inferred from the complete recordings. Next, we are going to study how the difference in thresholding alters our inference of the underlying network properties and how we can define a more sampling-independent thresholding strategy.}

{Purpose Macromolecular resonances (MM) arise mainly from cytosolic proteins and overlap with metabolites, influencing metabolite quantification. Macromolecules can serve as valuable biomarkers for diseases and pathologies. The objectives of this study were to characterize MM at 9.4T in the human brain (occipital and left parietal lobe) and to describe the RF coil setup used for MM acquisition in the two regions. Methods An adiabatic inversion pulse was optimised for metabolite nulling at 9.4T using double inversion recovery and was combined for the first time with metabolite cycled (MC) semi-LASER and appropriate coil configuration. MM spectra (seven volunteers) from two brain locations were averaged and smoothed creating MM templates, which were then parametrized using simulated Voigt-shaped lines within LCModel. Quantification was performed on individual data sets, including corrections for different tissue composition and the T1 and T2 relaxation of water. Results Our coil configuration method resulted in efficient math formula (\textgreater30 T/$\surd$kW) for both brain regions. The 15 MM components were detected and quantified in MM baselines of the two brain areas. No significant differences in concentration levels of MM between different regions were found. Two new MM peaks were reported (M7 M8). Conclusion Double inversion, which was combined with MC semi-LASER, enabled the acquisition of high spectral resolution MM spectra for both brain regions at 9.4T. The 15 MM components were detected and quantified. Two new MM peaks were reported for the first time (M7 M8) and preliminarily assigned to $\beta$-methylene protons of aspartyl-groups.}

{PURPOSE: The high chemical shift separation at 9.4 T allows for selective saturation of proton pools in exchange with water protons. For the first time, highly selective and comprehensive chemical exchange saturation transfer (CEST) experiments were performed in the human brain at 9.4 T. This work provides insight into CEST signals in the human brain in comparison with existing animal studies, as well as with CEST effects in vivo at lower field strengths. METHODS: A novel snapshot-CEST method for human brain scans at 9.4 T was optimized and employed for highly-spectrally-resolved (95 offsets) CEST measurements in healthy subjects and one brain tumor patient. Reproducibility and stability between scans was verified in grey and white matter after B0, B1, and motion correction of the acquired 3D CEST volumes. Two-step Lorentzian fitting was used to further improve separation of spectrally discernible signals to create known and novel CEST contrast maps at 9.4 T. RESULTS: At a saturation power of B1 \textequals 0.5 $\mu$T most selective CEST effects could be obtained in the human brain with high inter-scan reproducibility. While contrast behavior of previously measured signals at lower field, namely amide-, guanidyl- and NOE-CEST effects, could be reproduced, novel signals at 2.7 ppm, and -1.6 ppm could be verified in healthy subjects and in a brain tumor patient for the first time. CONCLUSION: High spectral resolution chemical exchange saturation transfer at 9.4 T allows deeper insights into the Z-spectrum structure of the human brain, and provides many different contrasts showing different correlations in healthy tissue and in tumor-affected areas of the brain, generating hypotheses for future investigations of in-vivo-CEST at UHF.}

{CEST benefits of ultra-high fields due to the better frequency separation(1,2). However, is this just a benefit for the interested MR scientist or is this also of use to address clinical questions? This can only be answered if CEST measurements of humans are performed at 7T or even 9.4T both available for human scans. While judgment about clinical benefits require larger studies, CEST in humans at UHF brings interesting preliminary insights and strong hypothesis generation.}

{Collaborative spatial search is an important task, for example, when firefighters or rescue teams search for victims within a building. In two experiments we examined the distinction between individual and collaborative search and the influence of common reference information on these two types of search. In Experiment 1, individuals and dyads were asked to walk through and fully cover virtual city environments of varied complexity displayed on head mounted displays. We recorded search time and missed locations. With increasing environmental size and resultant increasing memory load participants missed more target locations. Dyads showed longer added trajectories than individuals, but less self-overlap with their own trajectory (i.e., walking the same section multiple times). This suggests that the between-trajectories-overlap between searchers was responsible for the inefficient trajectories in collaborative search. In Experiment 2, we provided participants with a compass to facilitate organization of their searches. However, results were similar to those of Experiment 1. Mere orientation cues without a-priori environmental information seem insufficient to divide the search task and improve search performance.}

{In everyday life we come across numerous problem solving situations that we either resolve alone or in collaboration with another person. The aim of the present study was to examine the underlying cognitive mechanisms that are involved in collaborative problem solving using virtual reality technology. Participants worked either individually or in pairs (collaborative condition) to solve a virtual rubik\textquoterights cube type puzzle task. The puzzle-task included 9 cubes with different colours on different sides and a solution space with 4 empty cube positions. Participants were instructed to choose the correct cubes among the distractor ones and arrange them within the solution space such that each side of the solution space displayed a single color. In the collaborative condition participants stood opposite to each other, allowing for communication, and each person was represented within the virtual world by a virtual head and a virtual controller. Results showed that participants were faster in solving the task when they were working in pairs compared to individually. Moreover, they employed a strategy of dividing the cube space according to their physical position in space. Our conjecture is that pairs, given their location in space, had access to all relevant information of the problem at a single point in time, compared to individuals. That is, together they could view all sides and all colors of the solution space, whereas individuals had to remember the color of cubes that were not visible from their perspective (i.e. the back side of the solution space). In this interpretation access from multiple perspectives at once, as in the collaborative condition allows for better problem solving. In a follow up experiment, we are currently testing whether collaborative problem solving from adjacent problem solvers is similar to individual performance.}

{Ultra-high-field (UHF, $\geq$7 T) human magnetic resonance imaging (MRI) provides undisputed advantages over low-field MRI ($\leq$3 T), but its development remains challenging because of numerous technical issues, including the low efficiency of transmit (Tx) radiofrequency (RF) coils caused by the increase in tissue power deposition with frequency. Tight-fit human head transceiver (TxRx) arrays improve Tx efficiency in comparison with Tx-only arrays, which are larger in order to fit multi-channel receive (Rx)-only arrays inside. A drawback of the TxRx design is that the number of elements in an array is limited by the number of available high-power RF Tx channels (commonly 8 or 16), which is not sufficient for optimal Rx performance. In this work, as a proof of concept, we developed a method for increasing the number of Rx elements in a human head TxRx surface loop array without the need to move the loops away from a sample, which compromises the array Tx performance. We designed and constructed a prototype 16-channel tight-fit array, which consists of eight TxRx surface loops placed on a cylindrical holder circumscribing a head, and eight Rx-only vertical loops positioned along the central axis (parallel to the magnetic field B0) of each TxRx loop, perpendicular to its surface. We demonstrated both experimentally and numerically that the addition of the vertical loops has no measurable effect on the Tx efficiency of the array. An increase in the maximum local specific absorption rate (SAR), evaluated using two human head voxel models (Duke and Ella), measured 3.4 or less. At the same time, the 16-element array provided 30 improvement of central signal-to-noise ratio (SNR) in vivo relative to a surface loop eight-element array. The novel array design also demonstrated an improvement in the parallel Rx performance in the transversal plane. Thus, using this method, both the Rx and Tx performance of the human head array can be optimized simultaneously.}