Research Topics
| Fritjof HelmchenSummaryAffiliation: University of Zurich Country: Switzerland Publications
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Detail Information
Publications
Little strokes fill big oaks: a simple in vivo stain of brain cellsFritjof Helmchen
Department of Neurophysiology, Brain Research Institute, University of Zurich, CH 8057 Zurich, Switzerland
Neuron 53:771-3. 2007..Neuronal populations are sparsely labeled, preserving the ability to resolve calcium signals in dendrites and synaptic structures...- Deep tissue two-photon microscopyFritjof Helmchen
Department of Neurophysiology, Brain Research Institute, University of Zurich, CH 8057 Zurich, Switzerland
Nat Methods 2:932-40. 2005..Here we review fundamental concepts of nonlinear microscopy and discuss conditions relevant for achieving large imaging depths in intact tissue... 
High-speed in vivo calcium imaging reveals neuronal network activity with near-millisecond precisionBenjamin F Grewe
Department of Neurophysiology, Brain Research Institute, University of Zurich, Switzerland
Nat Methods 7:399-405. 2010..By revealing spike sequences in neuronal populations on a fast time scale, high-speed calcium imaging will facilitate optical studies of information processing in brain microcircuits...- Distinct functional properties of primary and posteromedial visual area of mouse neocortexMorgane M Roth
Department of Neurophysiology, Brain Research Institute, University of Zurich, CH 8057 Zurich, Switzerland
J Neurosci 32:9716-26. 2012..Together, PM is tuned for cardinal orientations, high SFs, and low speed and is further located between V1 and the retrosplenial cortex consistent with a role in processing natural scenes during spatial navigation... - Simultaneous BOLD fMRI and fiber-optic calcium recording in rat neocortexKristina Schulz
Department of Neurophysiology, Brain Research Institute, University of Zurich, Switzerland
Nat Methods 9:597-602. 2012..Our findings highlight the complexity of fMRI BOLD signals, involving both neuronal and glial activity. Combined fMRI and fiber-optic recordings should help to clarify cellular mechanisms underlying BOLD signals... - In vivo calcium imaging of neural network functionWerner Göbel
Department of Neurophysiology, Brain Research Institute, University of Zurich, Zurich, Switzerland
Physiology (Bethesda) 22:358-65. 2007..In this review, we discuss basic aspects of in vivo calcium imaging and highlight recent developments that will help to uncover operating principles of neural circuits... 
Neuron to astrocyte communication via cannabinoid receptors is necessary for sustained epileptiform activity in rat hippocampusGuyllaume Coiret
Brain Research Institute, University of Zurich, Zurich, Switzerland
PLoS ONE 7:e37320. 2012..Thus, endocannabinoid signaling from neurons to astrocytes represents an additional significant factor in the maintenance of epileptiform activity in the hippocampus...- New angles on neuronal dendrites in vivoWerner Göbel
Department of Neurophysiology, Brain Research Institute, Winterthurerstr 190, CH 8057, Zurich, Switzerland
J Neurophysiol 98:3770-9. 2007..These novel scanning modes will facilitate optical probing of dendritic function in vivo... - Post hoc immunostaining of GABAergic neuronal subtypes following in vivo two-photon calcium imaging in mouse neocortexDominik Langer
Department of Neurophysiology, Brain Research Institute, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
Pflugers Arch 463:339-54. 2012..Our approach is a general and flexible method to distinguish GABAergic subtypes in cell populations previously imaged in the living animal. It should thus facilitate dissecting the functional roles of these subtypes in neural circuitry... - Enhanced fluorescence signal in nonlinear microscopy through supplementary fiber-optic light collectionChristoph J Engelbrecht
Department of Neurophysiology, Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
Opt Express 17:6421-35. 2009..Moreover, SUFICS reduced noise levels in calcium imaging experiments by about 23%. We recommend SUFICS as a generally applicable, effective add-on to nonlinear microscopes for enhancing fluorescence signals... - Miniaturized selective plane illumination microscopy for high-contrast in vivo fluorescence imagingChristoph J Engelbrecht
Department of Neurophysiology, Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
Opt Lett 35:1413-5. 2010..The miniSPIM may thus enable novel in vivo imaging approaches... - In vivo Ca2+ imaging of dorsal horn neuronal populations in mouse spinal cordHelge C Johannssen
Department of Neurophysiology, Brain Research Institute, University of Zurich, Zurich, Switzerland
J Physiol 588:3397-402. 2010..Notably, in a subset of cells we resolved Ca(2+) transients evoked by mechanical stimulation of the paw. These advances open new opportunities to study both physiology and pathology of spinal cord neural circuits in vivo... - Chronic imaging of cortical sensory map dynamics using a genetically encoded calcium indicatorMatthias Minderer
Brain Research Institute, Department of Neurophysiology, University of Zurich, Switzerland
J Physiol 590:99-107. 2012..This method opens new possibilities for the longitudinal study of stability and plasticity of cortical sensory representations... - Optical probing of neuronal ensemble activityBenjamin F Grewe
Department of Neurophysiology, Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
Curr Opin Neurobiol 19:520-9. 2009..Optical probing of neuronal ensemble dynamics in vivo thus promises to reveal fundamental principles of neural circuit function and dysfunction... - Enhancement of CA3 hippocampal network activity by activation of group II metabotropic glutamate receptorsJeanne Ster
Brain Research Institute, University of Zurich, CH 8057 Zurich, Switzerland
Proc Natl Acad Sci U S A 108:9993-7. 2011..Thus, our data indicate that hippocampal responses are modulated not only by presynaptic mGluRIIs that reduce glutamate release but also by postsynaptic mGluRIIs that depolarize neurons and enhance CA3 network activity... - Selective regulation of NR2B by protein phosphatase-1 for the control of the NMDA receptor in neuroprotectionMélissa Farinelli
Brain Research Institute, University of Zurich, Zurich, Switzerland
PLoS ONE 7:e34047. 2012..They provide a new target for the development of potential therapeutic treatment of neurodegeneration... - Ultra-compact fiber-optic two-photon microscope for functional fluorescence imaging in vivoChristoph J Engelbrecht
Dept of Neurophysiology, Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
Opt Express 16:5556-64. 2008..The microscope will be easily portable by a rat or mouse and thus should enable functional imaging in freely behaving animals... - Representation of visual scenes by local neuronal populations in layer 2/3 of mouse visual cortexBjörn M Kampa
Brain Research Institute, Department of Neurophysiology, University of Zurich Zurich, Switzerland
Front Neural Circuits 5:18. 2011..Our results suggest a population code in layer 2/3 of visual cortex, where the visual environment is dynamically represented in the activation of distinct functional sub-networks... - Chapter 10. In vivo measurements of blood flow and glial cell function with two-photon laser-scanning microscopyFritjof Helmchen
Department of Neurophysiology, Brain Research Institute, University of Zurich, Zurich, Switzerland
Methods Enzymol 444:231-54. 2008..Further, we show how extensions of ultra-fast laser techniques lead to new models of stroke, where individual vessels may be targeted for occlusion with micrometer precision... - Imaging cellular network dynamics in three dimensions using fast 3D laser scanningWerner Göbel
Department of Neurophysiology, Brain Research Institute, University of Zurich, Winterthurerstr 190, CH 8057 Zurich, Switzerland
Nat Methods 4:73-9. 2007..Two-photon population imaging using 3D scanning opens the field for comprehensive studies of local network dynamics in intact tissue... - Calcium indicator loading of neurons using single-cell electroporationThomas Nevian
Abteilung Zellphysiologie, Max Planck Institut fur medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany
Pflugers Arch 454:675-88. 2007.... - In vivo calcium imaging of circuit activity in cerebellar cortexMegan R Sullivan
Department of Molecular Biology, Princeton University, Princeton, New Jersey, Princeton, NJ 08544, USA
J Neurophysiol 94:1636-44. 2005..Two-photon calcium imaging of bulk-loaded cerebellar cortex is thus well suited to optically monitor synaptic processing in the intact cerebellum... - Sulforhodamine 101 as a specific marker of astroglia in the neocortex in vivoAxel Nimmerjahn
Abteilung Zellphysiologie, , Jahnstr. 29, 69120 Heidelberg, Germany
Nat Methods 1:31-7. 2004..We expect SR101 staining to become a principal tool for investigating astroglia in vivo... - Supralinear Ca2+ influx into dendritic tufts of layer 2/3 neocortical pyramidal neurons in vitro and in vivoJack Waters
Abteilung Zellphysiologie, Max Planck Institut fur medizinische Forschung, 69120 Heidelberg, Germany
J Neurosci 23:8558-67. 2003..This dendritic supralinearity enables layer 2/3 neurons to integrate ascending sensory input from layer 4 and associative input to layer 1... - Raising the speed limit--fast Ca(2+) handling in dendritic spinesFritjof Helmchen
Abteilung Zellphysiologie, Max Planck Institute für medizinische Forschung, Jahnstr 29, 69120 Heidelberg, Germany
Trends Neurosci 25:438-41; discussion 441. 2002..In addition structural factors, such as shape and dendritic location, could contribute to fine-tuning of spine Ca2+ handling and synaptic modification... - Sindbis vector SINrep(nsP2S726): a tool for rapid heterologous expression with attenuated cytotoxicity in neuronsJinhyun Kim
Max-Planck Institute for Medical Research, Department of Molecular Neurobiology, Jahnstrasse 29, 69120 Heidelberg, Germany
J Neurosci Methods 133:81-90. 2004..As an experimental example, we demonstrate the applicability of this system for high-resolution two-photon imaging of dendritic spines in vivo... - Lentivirus-based genetic manipulations of cortical neurons and their optical and electrophysiological monitoring in vivoTanjew Dittgen
Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
Proc Natl Acad Sci U S A 101:18206-11. 2004..This approach is ideally suited for analysis of gene functions in individual neurons in the intact brain... - Imaging input and output of neocortical networks in vivoJason N D Kerr
Department of Cell Physiology, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
Proc Natl Acad Sci U S A 102:14063-8. 2005..The dissection of the various signal components in bulk-loaded tissue as demonstrated here will enable further studies of signal flow through cortical networks... - Boosting of action potential backpropagation by neocortical network activity in vivoJack Waters
Abteilung Zellphysiologie, Max Planck Institut fur medizinische Forschung, 69120 Heidelberg, Germany
J Neurosci 24:11127-36. 2004..Hence, somatic feedback to the dendrites becomes stronger with increasing network activity... - Background synaptic activity is sparse in neocortexJack Waters
Abteilung Zellphysiologie, Max Planck Institut fur medizinische Forschung, 69120 Heidelberg, Germany
J Neurosci 26:8267-77. 2006..These conditions enhance the effectiveness of each synapse at depolarized potentials. Hence, neocortical networks are relatively quiet at rest, and the effect of synaptic background is weaker than previously thought... - Miniaturized two-photon microscope based on a flexible coherent fiber bundle and a gradient-index lens objectiveWerner Göbel
Max Planck Institut fur medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany
Opt Lett 29:2521-3. 2004..Micrometer-sized fluorescent beads and pollen grains were readily resolved. In addition, fluorescently labeled blood vessels were imaged through the fiber bundle in rat brain in vivo... - Dendritic spikes in apical dendrites of neocortical layer 2/3 pyramidal neuronsMatthew Evan Larkum
Abteilung Zellphysiologie, Max Planck Institut fur medizinische Forschung, D 69120 Heidelberg, Germany
J Neurosci 27:8999-9008. 2007..We conclude that L2/3 pyramidal neurons can generate dendritic spikes, sharing with L5 pyramidal neurons fundamental properties of dendritic excitability and control by inhibition... - Nonlinear anisotropic diffusion filtering of three-dimensional image data from two-photon microscopyPhilip J Broser
Max Planck Institut fur medizinische Forschung, Abteilung Zellphysiologie, Jahnstr 29, D 69120, Heidelberg, Germany
J Biomed Opt 9:1253-64. 2004..The filter is a valuable general tool for smoothing cellular processes and is well suited for preparing data for subsequent image segmentation and neuron reconstruction... - Spatial organization of neuronal population responses in layer 2/3 of rat barrel cortexJason N D Kerr
Department of Cell Physiology, Max Planck Institute for Medical Research, D 69120 Heidelberg, Germany
J Neurosci 27:13316-28. 2007..We conclude that, despite their sparseness and variability, L2/3 population responses show a clear spatial organization on the columnar scale... - Novel approaches to monitor and manipulate single neurons in vivoMichael Brecht
Department of Neuroscience, Erasmus Medical Center, University Medical Center Rotterdam, 3015 DR Rotterdam, The Netherlands
J Neurosci 24:9223-7. 2004 - Ca2+ imaging in the mammalian brain in vivoFritjof Helmchen
Abteilung Zellphysiologie, Max Planck Insitut für medizinische Forschung, Jahnstr 29, 69120 Heidelberg, Germany
Eur J Pharmacol 447:119-29. 2002....