Publications

Empirical Inference Poster Koopman Spectral Analysis Uncovers the Temporal Structure of Spontaneous Neural Events Shao, K., Xu, Y., Logothetis, N., Shen, Z., Besserve, M. Computational and Systems Neuroscience Meeting (COSYNE), March 2024 (Published) URL BibTeX

Empirical Inference Poster LFP transient events in macaque subcortical areas reveal network coordination across scales and structures: a simultaneous fMRI-electrophysiology study Besserve, M., Safavi, S., Schölkopf, B., Logothetis, N. Computational and Systems Neuroscience Meeting (COSYNE), March 2024 (Published) URL BibTeX

Empirical Inference Poster Perception of temporal dependencies in autoregressive motion Meding, K., Schölkopf, B., Wichmann, F. A. Perception, 48(2-suppl):141, 42nd European Conference on Visual Perception (ECVP), August 2019 (Published) URL BibTeX

Empirical Inference Poster Phenomenal Causality and Sensory Realism Bruijns, S. A., Meding, K., Schölkopf, B., Wichmann, F. A. Perception, 48(2-suppl):141, 42nd European Conference on Visual Perception (ECVP), August 2019 (Published) URL BibTeX

Empirical Inference Poster Neural mass modeling of the Ponto-Geniculo-Occipital wave and its neuromodulation Shao, K., Logothetis, N., Besserve, M. 28th Annual Computational Neuroscience Meeting (CNS*2019), July 2019 (Published) DOI BibTeX

Empirical Inference Poster Representation of sensory uncertainty in macaque visual cortex Goris, R., Henaff, O., Meding, K. Computational and Systems Neuroscience (COSYNE), March 2018 (Published) BibTeX

Empirical Inference Poster Generalized phase locking analysis of electrophysiology data Safavi, S., Panagiotaropoulos, T., Kapoor, V., Logothetis, N. K., Besserve, M. 7th AREADNE Conference on Research in Encoding and Decoding of Neural Ensembles, 2018 (Published) URL BibTeX

Empirical Inference Poster Photorealistic Video Super Resolution Pérez-Pellitero, E., Sajjadi, M. S. M., Hirsch, M., Schölkopf, B. Workshop and Challenge on Perceptual Image Restoration and Manipulation (PIRM) at the 15th European Conference on Computer Vision (ECCV), 2018 (Published) BibTeX

Empirical Inference Poster Retinal image quality of the human eye across the visual field Meding, K., Hirsch, M., Wichmann, F. A. 14th Biannual Conference of the German Society for Cognitive Science (KOGWIS 2018), 2018 (Published) BibTeX

Empirical Inference Poster Improving performance of linear field generation with multi-coil setup by optimizing coils position Aghaeifar, A., Loktyushin, A., Eschelbach, M., Scheffler, K. Magnetic Resonance Materials in Physics, Biology and Medicine, 30(Supplement 1):S259, 34th Annual Scientific Meeting of the European Society for Magnetic Resonance in Medicine and Biology (ESMRMB 2017), October 2017 (Published) DOI URL BibTeX

Empirical Inference Poster Estimating B0 inhomogeneities with projection FID navigator readouts Loktyushin, A., Ehses, P., Schölkopf, B., Scheffler, K. 25th Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2017), April 2017 (Published) URL BibTeX

Empirical Inference Poster Image Quality Improvement by Applying Retrospective Motion Correction on Quantitative Susceptibility Mapping and R2* Feng, X., Loktyushin, A., Deistung, A., Reichenbach, J. 25th Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2017), April 2017 (Published) URL BibTeX

Empirical Inference Poster Generalized phase locking analysis of electrophysiology data Safavi, S., Panagiotaropoulos, T., Kapoor, V., Logothetis, N. K., Besserve, M. ESI Systems Neuroscience Conference (ESI-SyNC 2017): Principles of Structural and Functional Connectivity, 2017 (Published) BibTeX

Empirical Inference Poster Autofocusing-based correction of B0 fluctuation-induced ghosting Loktyushin, A., Ehses, P., Schölkopf, B., Scheffler, K. 24th Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2016), May 2016 (Published) URL BibTeX

Empirical Inference Poster PGO wave-triggered functional MRI: mapping the networks underlying synaptic consolidation Logothetis, N. K., Murayama, Y., Ramirez-Villegas, J. F., Besserve, M., Evrard, H. 47th Annual Meeting of the Society for Neuroscience (Neuroscience 2016), 2016 BibTeX

Empirical Inference Poster Hippocampal neural events predict ongoing brain-wide BOLD activity Besserve, M., Logothetis, N. K. 47th Annual Meeting of the Society for Neuroscience (Neuroscience 2016), 2016 BibTeX

Empirical Inference Poster Statistical source separation of rhythmic LFP patterns during sharp wave ripples in the macaque hippocampus Ramirez-Villegas, J. F., Logothetis, N. K., Besserve, M. 47th Annual Meeting of the Society for Neuroscience (Neuroscience 2016), 2016 BibTeX

Empirical Inference Poster Diversity of sharp wave-ripples in the CA1 of the macaque hippocampus and their brain wide signatures Ramirez-Villegas, J. F., Logothetis, N. K., Besserve, M. 45th Annual Meeting of the Society for Neuroscience (Neuroscience 2015), October 2015 (Published) URL BibTeX

Empirical Inference Poster Improving Quantitative Susceptibility and R2* Mapping by Applying Retrospective Motion Correction Feng, X., Loktyushin, A., Deistung, A., Reichenbach, J. R. 23rd Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine, ISMRM, June 2015 (Published) BibTeX

Empirical Inference Poster Retrospective rigid motion correction of undersampled MRI data Loktyushin, A., Babayeva, M., Gallichan, D., Krueger, G., Scheffler, K., Kober, T. 23rd Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine, ISMRM, June 2015 (Published) BibTeX

Empirical Inference Poster Calibrating the pixel-level Kepler imaging data with a causal data-driven model Wang, D., Foreman-Mackey, D., Hogg, D., Schölkopf, B. Workshop: 225th American Astronomical Society Meeting 2015 , 258.08, 2015 (Published) Web URL BibTeX

Empirical Inference Poster Disparity estimation from a generative light field model Köhler, R., Schölkopf, B., Hirsch, M. IEEE International Conference on Computer Vision (ICCV 2015), Workshop on Inverse Rendering, 2015, Note: This work has been presented as a poster and is not included in the workshop proceedings. BibTeX

Empirical Inference Poster Increasing the sensitivity of Kepler to Earth-like exoplanets Foreman-Mackey, D., Hogg, D., Schölkopf, B., Wang, D. Workshop: 225th American Astronomical Society Meeting 2015 , 105.01D, 2015 (Published) Web URL BibTeX

Empirical Inference Poster Cluster analysis of sharp-wave ripple field potential signatures in the macaque hippocampus Ramirez-Villegas, J. F., Logothetis, N. K., Besserve, M. Computational and Systems Neuroscience Meeting (COSYNE 2014), 2014 (Published) BibTeX

Empirical Inference Poster Dynamical source analysis of hippocampal sharp-wave ripple episodes Ramirez-Villegas, J. F., Logothetis, N. K., Besserve, M. Bernstein Conference, 2014 (Published) DOI BibTeX

Empirical Inference Poster FID-guided retrospective motion correction based on autofocusing Babayeva, M., Loktyushin, A., Kober, T., Granziera, C., Nickisch, H., Gruetter, R., Krueger, G. Joint Annual Meeting ISMRM-ESMRMB 2014, Milano, Italy, 2014 BibTeX

Empirical Inference Poster Analyzing locking of spikes to spatio-temporal patterns in the macaque prefrontal cortex Safavi, S., Panagiotaropoulos, T., Kapoor, V., Logothetis, N., Besserve, M. Bernstein Conference, 2013 DOI BibTeX

Empirical Inference Poster Characterization of different types of sharp-wave ripple signatures in the CA1 of the macaque hippocampus Ramirez-Villegas, J., Logothetis, N., Besserve, M. 4th German Neurophysiology PhD Meeting Networks, 2013 Web BibTeX

Empirical Inference Poster Coupling between spiking activity and beta band spatio-temporal patterns in the macaque PFC Safavi, S., Panagiotaropoulos, T., Kapoor, V., Logothetis, N., Besserve, M. 43rd Annual Meeting of the Society for Neuroscience (Neuroscience 2013), 2013 BibTeX

Empirical Inference Poster Domain Generalization via Invariant Feature Representation Muandet, K., Balduzzi, D., Schölkopf, B. 30th International Conference on Machine Learning (ICML2013), 2013 PDF BibTeX

Empirical Inference Poster Gaussian Process Vine Copulas for Multivariate Dependence Lopez-Paz, D., Hernandez-Lobato, J., Ghahramani, Z. International Conference on Machine Learning (ICML 2013), 2013 (Published) PDF BibTeX

Empirical Inference Poster One-class Support Measure Machines for Group Anomaly Detection Muandet, K., Schölkopf, B. 29th Conference on Uncertainty in Artificial Intelligence (UAI 2013), 2013 PDF BibTeX

Empirical Inference Probabilistic Numerics Poster The Randomized Dependence Coefficient Lopez-Paz, D., Hennig, P., Schölkopf, B. Neural Information Processing Systems (NIPS 2013), 2013 PDF BibTeX

Empirical Inference Poster Blind Retrospective Motion Correction of MR Images Loktyushin, A., Nickisch, H., Pohmann, R., Schölkopf, B. 20th Annual Scientific Meeting ISMRM, May 2012

Abstract ›

Patient motion in the scanner is one of the most challenging problems in MRI. We propose a new retrospective motion correction method for which no tracking devices or specialized sequences are required. We seek the motion parameters such that the image gradients in the spatial domain become sparse. We then use these parameters to invert the motion and recover the sharp image. In our experiments we acquired 2D TSE images and 3D FLASH/MPRAGE volumes of the human head. Major quality improvements are possible in the 2D case and substantial improvements in the 3D case.

Web BibTeX

Empirical Inference Poster Centrality of the Mammalian Functional Brain Network Besserve, M., Bartels, A., Murayama, Y., Logothetis, N. 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012), 2012 BibTeX

Empirical Inference Poster Evaluation of Whole-Body MR-Based Attenuation Correction in Bone and Soft Tissue Lesions Bezrukov, I., Mantlik, F., Schmidt, H., Schwenzer, N., Brendle, C., Schölkopf, B., Pichler, B. Nuclear Science Symposium and Medical Imaging Conference (NSS-MIC 2012), 2012 (Published) BibTeX

Empirical Inference Poster Identifying endogenous rhythmic spatio-temporal patterns in micro-electrode array recordings Besserve, M., Panagiotaropoulos, T., Crocker, B., Kapoor, V., Tolias, A., Panzeri, S., Logothetis, N. 9th annual Computational and Systems Neuroscience meeting (Cosyne 2012), 2012 BibTeX

Empirical Inference Poster Juggling Increases Interhemispheric Brain Connectivity: A Visual and Quantitative dMRI Study. Schultz, T., Gerber, P., Schmidt-Wilcke, T. Vision, Modeling and Visualization (VMV 2012), 2012 BibTeX

Empirical Inference Poster Kernel Mean Embeddings of POMDPs Nishiyama, Y., Boularias, A., Gretton, A., Fukumizu, K. 21st Machine Learning Summer School , 2012 BibTeX

Empirical Inference Poster Learning from Distributions via Support Measure Machines Muandet, K., Fukumizu, K., Dinuzzo, F., Schölkopf, B. 26th Annual Conference on Neural Information Processing Systems (NIPS 2012), 2012 PDF BibTeX

Empirical Inference Poster Multi-modal Learning for Dynamic Tactile Sensing. (IROS 2012 Workshop on Advances in tactile sensing and touch-based human-robot interaction) Kroemer, O., Lampert, C., Peters, J. 2012 BibTeX

Empirical Inference Poster Reconstruction using Gaussian mixture models Joubert, P., Habeck, M. 2012 Gordon Research Conference on Three-Dimensional Electron Microscopy (3DEM), 2012 Web BibTeX

Empirical Inference Poster Semi-Supervised Domain Adaptation with Copulas Lopez-Paz, D., Hernandez-Lobato, J., Schölkopf, B. Neural Information Processing Systems (NIPS 2012), 2012 PDF BibTeX

Empirical Inference Poster The PET Performance Measurements of A Next Generation Dedicated Small Animal PET/MR Scanner Liu, C., Hossain, M., Bezrukov, I., Wehrl, H., Kolb, A., Judenhofer, M., Pichler, B. World Molecular Imaging Congress (WMIC 2012), 2012 BibTeX

Empirical Inference Poster The geometry and statistics of geometric trees Feragen, A., Lo, P., de Bruijne, M., Nielsen, M., Lauze, F. T{\"u}bIt day of bioinformatics, June, 2012 BibTeX

Empirical Inference Poster Therapy monitoring of patients with chronic sclerodermic graft-versus-host-disease using PET/MRI Sauter, A., Schmidt, H., Mantlik, F., Kolb, A., Federmann, B., Bethge, W., Reimold, M., Pfannenberg, C., Pichler, B., Horger, M. 2012 SNM Annual Meeting, 2012 Web BibTeX

Empirical Inference Poster Spatiotemporal mapping of rhythmic activity in the inferior convexity of the macaque prefrontal cortex Panagiotaropoulos, T., Besserve, M., Crocker, B., Kapoor, V., Tolias, A., Panzeri, S., Logothetis, N. 41(239.15), 41st Annual Meeting of the Society for Neuroscience (Neuroscience 2011), November 2011

Abstract ›

The inferior convexity of the macaque prefrontal cortex (icPFC) is known to be involved in higher order processing of sensory information mediating stimulus selection, attention and working memory. Until now, the vast majority of electrophysiological investigations of the icPFC employed single electrode recordings. As a result, relatively little is known about the spatiotemporal structure of neuronal activity in this cortical area. Here we study in detail the spatiotemporal properties of local field potentials (LFP's) in the icPFC using multi electrode recordings during anesthesia. We computed the LFP-LFP coherence as a function of frequency for thousands of pairs of simultaneously recorded sites anterior to the arcuate and inferior to the principal sulcus. We observed two distinct peaks of coherent oscillatory activity between approximately 4-10 and 15-25 Hz. We then quantified the instantaneous phase of these frequency bands using the Hilbert transform and found robust phase gradients across recording sites. The dependency of the phase on the spatial location reflects the existence of traveling waves of electrical activity in the icPFC. The dominant axis of these traveling waves roughly followed the ventral-dorsal plane. Preliminary results show that repeated visual stimulation with a 10s movie had no dramatic effect on the spatial structure of the traveling waves. Traveling waves of electrical activity in the icPFC could reflect highly organized cortical processing in this area of prefrontal cortex.

Web BibTeX

Empirical Inference Poster Atlas- and Pattern Recognition Based Attenuation Correction on Simultaneous Whole-Body PET/MR Bezrukov, I., Schmidt, H., Mantlik, F., Schwenzer, N., Hofmann, M., Schölkopf, B., Pichler, B. 2011(MIC18.M-116), 2011 IEEE Nuclear Science Symposium, Medical Imaging Conference (NSS-MIC 2011), October 2011

Abstract ›

With the recent availability of clinical whole-body PET/MRI it is possible to evaluate and further develop MR-based attenuation correction methods using simultaneously acquired PET/MR data. We present first results for MRAC on patient data acquired on a fully integrated whole-body PET/MRI (Biograph mMR, Siemens) using our method that applies atlas registration and pattern recognition (ATPR) and compare them to the segmentation-based (SEG) method provided by the manufacturer. The ATPR method makes use of a database of previously aligned pairs of MR-CT volumes to predict attenuation values on a continuous scale. The robustness of the method in presence of MR artifacts was improved by location and size based detection. Lesion to liver and lesion to blood ratios (LLR and LBR) were compared for both methods on 29 iso-contour ROIs in 4 patients. ATPR showed >20% higher LBR and LLR for ROIs in and >7% near osseous tissue. For ROIs in soft tissue, both methods yielded similar ratios with max. differences <6% . For ROIs located within metal artifacts in the MR image, ATPR showed >190% higher LLR and LBR than SEG, where ratios <0.1 occured. For lesions in the neighborhood of artifacts, both ratios were >15% higher for ATPR. If artifacts in MR volumes caused by metal implants are not accounted for in the computation of attenuation maps, they can lead to a strong decrease of lesion to background ratios, even to disappearance of hot spots. Metal implants are likely to occur in the patient collective receiving combined PET/MR scans, of our first 10 patients, 3 had metal implants. Our method is currently able to account for artifacts in the pelvis caused by prostheses. The ability of the ATPR method to account for bone leads to a significant increase of LLR and LBR in osseous tissue, which supports our previous evaluations with combined PET/CT and PET/MR data. For lesions within soft tissue, lesion to background ratios of ATPR and SEG were comparable.

Web BibTeX

Empirical Inference Poster Evaluation and Optimization of MR-Based Attenuation Correction Methods in Combined Brain PET/MR Mantlik, F., Hofmann, M., Bezrukov, I., Schmidt, H., Kolb, A., Beyer, T., Reimold, M., Schölkopf, B., Pichler, B. 2011(MIC18.M-96), 2011 IEEE Nuclear Science Symposium, Medical Imaging Conference (NSS-MIC 2011), October 2011

Abstract ›

Combined PET/MR provides simultaneous molecular and functional information in an anatomical context with unique soft tissue contrast. However, PET/MR does not support direct derivation of attenuation maps of objects and tissues within the measured PET field-of-view. Valid attenuation maps are required for quantitative PET imaging, specifically for scientific brain studies. Therefore, several methods have been proposed for MR-based attenuation correction (MR-AC). Last year, we performed an evaluation of different MR-AC methods, including simple MR thresholding, atlas- and machine learning-based MR-AC. CT-based AC served as gold standard reference. RoIs from 2 anatomic brain atlases with different levels of detail were used for evaluation of correction accuracy. We now extend our evaluation of different MR-AC methods by using an enlarged dataset of 23 patients from the integrated BrainPET/MR (Siemens Healthcare). Further, we analyze options for improving the MR-AC performance in terms of speed and accuracy. Finally, we assess the impact of ignoring BrainPET positioning aids during the course of MR-AC. This extended study confirms the overall prediction accuracy evaluation results of the first evaluation in a larger patient population. Removing datasets affected by metal artifacts from the Atlas-Patch database helped to improve prediction accuracy, although the size of the database was reduced by one half. Significant improvement in prediction speed can be gained at a cost of only slightly reduced accuracy, while further optimizations are still possible.

Web BibTeX

Empirical Inference Poster Model based reconstruction for GRE EPI Blecher, W., Pohmann, R., Schölkopf, B., Seeger, M. Magnetic Resonance Materials in Physics, Biology and Medicine, 24(Supplement 1):493-494, 28th Annual Scientific Meeting ESMRMB, October 2011

Abstract ›

Model based nonlinear image reconstruction methods for MRI [3] are at the heart of modern reconstruction techniques (e.g.compressed sensing [6]). In general, models are expressed as a matrix equation where y and u are column vectors of k-space and image data, X model matrix and e independent noise. However, solving the corresponding linear system is not tractable. Therefore fast nonlinear algorithms that minimize a function wrt.the unknown image are the method of choice: In this work a model for gradient echo EPI, is proposed that incorporates N/2 Ghost correction and correction for field inhomogeneities. In addition to reconstruction from full data, the model allows for sparse reconstruction, joint estimation of image, field-, and relaxation-map (like [5,8] for spiral imaging), and improved N/2 ghost correction.

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