Prof. Dr. Fritjof Helmchen

 

Main Goals, Keywords

Principles of single-cell and neural network computation in the mammalian neocortex. In vivo analysis of spontaneous, sensory-evoked, and behavior-related neural activity. Neuron-glia relationships. (Synaptic integration, dendrites, excitability, synaptic plasticity, action potentials, population activity, cortical column, microcircuits)

Group Members

1 professor, 1 scientific coordinator, 9 postdocs, 9 PhD students, 2 technicians

Previous and Current Research

The outside-world is represented in the brain by the concerted activity of neuronal ensembles. We are interested how information is encoded and processed in neuronal assemblies within the local microcircuits of the intact neocortex. We are characterizing the properties of individual neurons in vivo and investigate how synaptic inputs are integrated in their dendrites to eventually cause action potentials that are transmitted to target neurons. Using in vivo electrophysiology and 2-photon imaging we perform both intracellular recordings from individual neurons as well as optical measurements of population activity. Development of 2-photon microscopy techniques for high-resolution imaging in living and behaving rodents.

Future Projects

Characterization of single-cell and network activity patterns in rat neocortex upon sensory stimulation (tactile, visual, or auditory) and during motor behaviour. Studies of the functional role of different classes of inhibitory interneurons. Development of tools for analyzing neuronal population dynamics. In vivo studies of dendritic integration in neocortical pyramidal neurons

Techniques and Equipment

2-photon laser-scanning microscopy, electrophysiology, in vivo patch-clamp recordings, in vivo long-term imaging, fiber-optic miniaturized microscopy, histological neuron reconstruction, single-cell and network simulations.

Selected Publications

• Grewe, B.F., Langer, D., Kasper, H., Kampa, B.M., Helmchen, F. High-speed in vivo calcium imaging reveals neuronal network activity with near-millisecond precision. Nat Methods. May; 7(5): 399-405 (2010). Epub 2010 Apr 18.
• Engelbrecht, C.E., Voigt, F., Helmchen, F. Miniaturized selective plane illumination microscopy (miniSPIM) for high-contrast in vivo fluorescence imaging. Optics Letters 35(9): 1413-1415 (2010).
• Engelbrecht, C.J., Voigt, F., Helmchen, F. Miniaturized selective plane illumination microscopy for high-contrast in vivo fluorescence imaging. Opt Lett. May 1; 35(9): 1413-5 (2010).
  

Funding

Swiss National Science Foundation, SystemsX.ch, EU-FP7 projects “Brain-i-Nets”, “PLASTICISE”, “Spacebrain”, “BrainScaleS”; German-Swiss Research Group "BaCoFun"

URL

www.hifo.uzh.ch/research/neurophysiology.html