Event archive

Room: Charlotte Buehler Room (C402) Location: MPI for Human Cognitive and Brain Sciences

Justin Haldar | Constrained Magnetic Resonance Imaging and the Blessings of Dimensionality

Guest Lecture
Magnetic resonance (MR) imaging technologies provide unique capabilities to probe the mysteries of biological systems, and have enabled novel insights into anatomy, metabolism, and physiology in both health and disease. However, while MRI is decades old, is associated with multiple Nobel prizes (in physics, chemistry, and medicine), and has already revolutionized fields like medicine and neuroscience, current MRI methods are still very far from achieving the full potential of the MRI signal. In particular, traditional methods are based on classical sampling theory, and suffer from fundamental trade-offs between signal-to-noise ratio, spatial resolution, and data acquisition speed. These issues are exacerbated in high-dimensional applications, due to the curse of dimensionality. Our work addresses the limitations of traditional MR imaging using signal processing approaches that are enabled by modern computational capabilities. These approaches are possible because of certain "blessings of dimensionality," e.g., that high-dimensional data often possess unexpectedly simple structure that can be exploited to alleviate classical barriers to fast high-resolution imaging. This seminar will describe approaches we have developed that use novel constrained imaging models to guide the design of new MR data acquisition and image reconstruction methods, and enable substantial acceleration of both low-dimensional and high-dimensional MR imaging experiments. [more]

Prof. Christian Langkammer | Post-mortem MRI for the validation of quantitative MRI parameters

Guest Lecture
MRI signal generation is substantially influenced by factors such as water content, iron, myelin, and several other contributors. Iron levels can be directly assessed using mass spectrometry, while the quantitative impacts of myelin's structure and composition remain unknown to a certain extent and are often inferred from theoretical simulations. Additionally, MRI relaxation rates and susceptibility are sensitive to these tissue constituents, but their specificity is limited. In this context, post-mortem investigations utilizing complementary methods such as TEM, LA-ICP-MS, MALDI-MSI, CARS, and SAXS-TT provide unique insights for the validation and understanding of quantitative MRI parameters. However, in-situ post-mortem MRI has to accommodate for factors like variable temperature, deoxygenated blood, and perfusion. Furthermore, the process of formalin fixation introduces a significant confounder, often obstructing direct conclusions. In this presentation, I aim to summarize our work on translating post-mortem MRI findings to in-vivo conditions, outline the analytical methods used to assess brain tissue structure and composition, and discuss potential collaborations with the MPI CBS. [more]

PhD Robert Barry | Realizing sub-second and sub-millimeter spinal cord fMRI at 7 Tesla

Guest Lecture
Magnetic resonance imaging of the human spinal cord at 7 Tesla offers new opportunities to visualize structures with high spatial resolution and enhanced conspicuity, and to detect functional networks with greater sensitivity. Sub-millimeter in-plane fMRI acquisitions are desirable and achievable, but published studies have had modest temporal resolution (>2 sec). Using a custom-built 7T pTx spine coil, we demonstrate sub-second and sub-millimeter cervical cord fMRI for the first time. Employing a 3D multi-shot sequence with appropriate phase corrections and NORDIC denoising, our data demonstrate temporal signal-to-noise ratios comparable to those of supra-second protocols, and we replicate bilateral functional connectivity patterns previously published in the cord. Realizing sub-second and sub-millimeter spinal cord fMRI opens new avenues of discovery that echo what has been reported through high spatiotemporal resolution brain fMRI. [more]

PhD Daniel Papp | B1+ shimming for the cervical spinal cord at 7T (and B0 shimming at 3T)

Guest Lecture
Several Parallel Transmit (pTX), capable coils have become available at 7T in the last few years. With pTx comes the ability to shape the excitation field to our needs. However, while pTx applications have seen great uptake in brain and body imaging, their use for the spinal cord has been limited so far. In this talk, we will demonstrate the feasibility of designing and deploying Universal Pulses for the cervical spinal cord at 7T. We will also show the first results in subject-specific B1+ shimming for the c-spine, using a dedicated Shimming Toolbox developed in our lab. Both approaches allow us to improve the signal homogeneity and thus deliver better image contrast for high-field spinal cord imaging. Finally, we will demonstrate the utility of the Shimming Toolbox for dynamic B0 field corrections in the cervical spine at clinical field strengths. [more]

| Software Solutions for Modeling and Analyzing Brain Dynamics at Different Scales

Workshop

Prof. Alison R. Preston | Hippocampal-prefrontal hierarchical representations of experience guide generalization and inference

Mind Meeting
Talk will be postponed [more]

Professor Dr Bradley C. Love | A common mechanism for spatial and concept learning

Mind Meeting

Dr Monika Schönauer | Imaging memory consolidation in wakefulness and sleep

Mind Meeting

Dr Patricia Lockwood | Neurocomputational basis of social learning and decision-making

Guest Lecture

Prof. Nicholas Turk-Browne | Rethinking memory systems for statistical learning

Mind Meeting
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