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Burg bei Magdeburg, Germany

Krautwald K.,Functional Neuroimaging Group | Angenstein F.,Leibniz Institute for Neurobiology Magdeburg | Angenstein F.,Otto Von Guericke University of Magdeburg | Angenstein F.,Center for Behavioural Brain science
Journal of Cerebral Blood Flow and Metabolism | Year: 2012

To study how various anesthetics affect the relationship between stimulus frequency and generated functional magnetic resonance imaging (fMRI) signals in the rat dentate gyrus, the perforant pathway was electrically stimulated with repetitive low frequency (i.e., 0.625, 1.25, 2.5, 5, and 10 Hz) stimulation trains under isoflurane/N 2 O, isoflurane, medetomidine, and α-chloralose. During stimulation, the blood oxygen level-dependent signal intensity (BOLD response) and local field potentials in the dentate gyrus were simultaneously recorded to prove whether the present anesthetic controls the generation of a BOLD response via targeting general hemodynamic parameters, by affecting mechanisms of neurovascular coupling, or by disrupting local signal processing. Using this combined electrophysiological/fMRI approach, we found that the threshold frequency (i.e., the minimal frequency required to trigger significant BOLD responses), the optimal frequency (i.e., the frequency that elicit the strongest BOLD response), and the spatial distribution of generated BOLD responses are specific for each anesthetic used. Concurrent with anesthetic-dependent characteristics of the BOLD response, we found the pattern of stimulus-induced neuronal activity in the dentate gyrus is also specific for each anesthetic. Consequently, the anesthetic-specific influence on local signaling processes is the underlying cause for the observation that an identical stimulus elicits different BOLD responses under various anesthetics. © 2012 ISCBFM All rights reserved. Source

Siegmund J.,Otto Von Guericke University of Magdeburg | Brechmann A.,Leibniz Institute for Neurobiology Magdeburg | Apel S.,University of Passau | Kastner C.,University of Marburg | And 3 more authors.
Proceedings of the ACM SIGSOFT 20th International Symposium on the Foundations of Software Engineering, FSE 2012 | Year: 2012

Program comprehension is an often evaluated, internal cognitive process. In neuroscience, functional magnetic resonance imaging (fMRI) is used to visualize such internal cognitive processes. We propose an experimental design to measure program comprehension based on fMRI. In the long run, we hope to answer questions like What distinguishes good programmers from bad programmers? or What makes a good programmer? © 2012 ACM. Source

Dieterich D.C.,Otto Von Guericke University of Magdeburg | Dieterich D.C.,Leibniz Institute for Neurobiology Magdeburg | Dieterich D.C.,Leibniz Institute for Neurobiology | Kreutz M.R.,Leibniz Institute for Neurobiology | Kreutz M.R.,Center for Behavioral Brain science
Molecular and Cellular Proteomics | Year: 2016

The advances in mass spectrometry based proteomics in the past 15 years have contributed to a deeper appreciation of protein networks and the composition of functional synaptic protein complexes. However, research on protein dynamics underlying core mechanisms of synaptic plasticity in brain lag far behind. In this review, we provide a synopsis on proteomic research addressing various aspects of synaptic function. We discuss the major topics in the study of protein dynamics of the chemical synapse and the limitations of current methodology. We highlight recent developments and the future importance of multidimensional proteomics and metabolic labeling. Finally, emphasis is given on the conceptual framework of modern proteomics and its current shortcomings in the quest to gain a deeper understanding of synaptic plasticity. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc. Source

Kanowski M.,Otto Von Guericke University of Magdeburg | Voges J.,Otto Von Guericke University of Magdeburg | Voges J.,Leibniz Institute for Neurobiology Magdeburg | Buentjen L.,Otto Von Guericke University of Magdeburg | And 5 more authors.
American Journal of Neuroradiology | Year: 2014

BACKGROUND AND PURPOSE: The morphology of the human thalamus shows high interindividual variability. Therefore, direct visualization of landmarks within the thalamus is essential for an improved definition of electrode positions for deep brain stimulation. The aim of this study was to provide anatomic detail in the thalamus by using inversion recovery TSE imaging at 7T. MATERIALS AND METHODS: The MR imaging protocol was optimized on 1 healthy subject to segment thalamic nuclei from one another. Final images, acquired with 0.52-mm2in-plane resolution and 3-mm section thickness, were compared with stereotactic brain atlases to assign visualized details to known anatomy. The robustness of the visualization of thalamic nuclei was assessed with 4 healthy subjects at lower image resolution. RESULTS: Thalamic subfields were successfully delineated in the dorsal aspect of the lateral thalamus. T1-weighting was essential. MR images had an appearance very similar to that of myelin-stained sections seen in brain atlases. Visualized intrathalamic structures were, among others, the lamella medialis, the external medullary lamina, the reticulatum thalami, the nucleus centre médian, the boundary between the nuclei dorso-oralis internus and externus, and the boundary between the nuclei dorso-oralis internus and zentrolateralis intermedius internus. CONCLUSIONS: Inversion recovery-prepared TSE imaging at 7T has a high potential to reveal fine anatomic detail in the thalamus, which may be helpful in enhancing the planning of stereotactic neurosurgery in the future. Source

Gellerich F.N.,Leibniz Institute for Neurobiology Magdeburg | Gellerich F.N.,Otto Von Guericke University of Magdeburg | Gizatullina Z.,Leibniz Institute for Neurobiology Magdeburg | Gainutdinov T.,Academy of Science of the Republic Tatarstan | And 5 more authors.
IUBMB Life | Year: 2013

This review focuses on problems of the intracellular regulation of mitochondrial function in the brain via the (i) supply of mitochondria with ADP by means of ADP shuttles and channels and (ii) the Ca2+ control of mitochondrial substrate supply. The permeability of the mitochondrial outer membrane for adenine nucleotides is low. Therefore rate dependent concentration gradients exist between the mitochondrial intermembrane space and the cytosol. The existence of dynamic ADP gradients is an important precondition for the functioning of ADP shuttles, for example CrP-shuttle. Cr at mM concentrations instead of ADP diffuses from the cytosol through the porin pores into the intermembrane space. The CrP-shuttle isoenzymes work in different directions which requires different metabolite concentrations mainly caused by dynamic ADP compartmentation. The ADP shuttle mechanisms alone cannot explain the load dependent changes in mitochondrial energization, and a complete model of mitochondrial regulation have to account the Ca2+-dependent substrate supply too. According to the old paradigmatic view, Ca2+ cyt taken up by the mitochondrial Ca2+ uniporter activates dehydrogenases within the matrix. However, recently it was found that Ca 2+ cyt at low nM concentrations exclusively activates the state 3 respiration via aralar, the mitochondrial glutamate/aspartate carrier. At higher Ca2+ cyt (> 500 nM), brain mitochondria take up Ca2+ for activation of substrate oxidation rates. Since brain mitochondrial pyruvate oxidation is only slightly influenced by Ca 2+ cyt, it was proposed that the cytosolic formation of pyruvate from its precursors is tightly controlled by the Ca 2+dependent malate/aspartate shuttle. At low (50-100 nM) Ca 2+ cyt the pyruvate formation is suppressed, providing a substrate limitation control in neurons. This so called "gas pedal" mechanism explains why the energy metabolism of neurons in the nucleus suprachiasmaticus could be down-regulated at night but activated at day as a basis for the circadian changes in Ca2+ cyt. It also could explain the energetic disadvantages caused by altered Ca2+ cyt at mitochondrial diseases and neurodegeneration. © 2013 IUBMB Life, 65(3):180-190, 2013 Copyright © 2013 International Union of Biochemistry and Molecular Biology, Inc. Source

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