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Photo-activation of excitable cells has proved to be a powerful tool to study connectivity patterns in neuronal slice tissue. In a conventional mapping experiment an intracellular recording from a single cell in the slice is established. The light beam is consecutively focused onto different locations within the surrounding tissue, eliciting spikes in the local cells. These spikes can be detected as postsynaptic events in the intracellular recording if a functional connection is present within the tissue. A connectivity map can be generated from the location of light irradiation and the postsynaptic response measurement. The SLP 40 has an extraordinarily wide projection range of 3.6 by 5.2 mm and allows for an extremely flexible choice of stimulation parameters for each presynaptic location. In addition, the SLP 40 can be used in dynamic stimulation paradigms and, optionally, upgraded for parallel stimulation of multiple sites.
The SLP 40 is used to project a spatial light pattern into the measurement chamber, employing an ordinary arc lamp as the light source. Our device can operate independently from the microscope optics. The SLP 40 is moved into the transmission light path of a fixed stage microscope right beneath the recording chamber. The spatial-temporal light pattern is generated using a DMD (digital mirror device).
Complete Software Control
The SLP 40 software in its basic version is optimized for generation of neuronal connectivity maps.
The software integrates the control of various camera systems, the DMD board, the light source, the SLP translation system, and communicates with the PATCHMASTER software for electrophysiological recordings.
The user can first acquire an image of the brain slice. In an interactive way, the stimulation parameters can be adjusted. A region for map generation can be easily defined by a few mouse clicks. Before experiment execution, the software generates a series of light stimulations optimized for a minimum of spatio-temporal interference.
During stimulation, electrophysiological data are continuously read from the PATCHMASTER software and overlayed on the image of the neuronal slice. In addition, one parameter analyzed from the data can be visualized using pseudo colors.
Offline import of electrophysiology data from other systems is possible via a XML-interface.
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Main Features:
- independent of microscope optics
- compatible with upright microscopes from Zeiss, Olympus, Nikon and Leica
- stimulation area not limited to field of view of the objective
- sequential and simultaneous (optional) stimulation
- SLP 40 positioning and calibration tools
- overlay of video image, electrophysiological recordings and pseudo-color map
- on-line analysis and display of the maps
- integration with HEKA EPC 10 patch clamp system
Applications:
- connectivity studies in acute slices of neuronal tissue
- studies of dynamic signal integration in single cells
- targeted release of caged compounds
- photo-bleaching
System Components:
- 200W mercury-xenon light source
- SLP 40 positioning system (one axis motorized)
- DMD optics and control electronics
- SLP 40 software
Options and Accessories:
- video imaging system
- upright fixed stage microscope
- fixed stage with slice chamber
- microscope translation system
- micromanipulator system
- patch clamp amplifier system
Technical Specifications:
- area of illumination: 3.6 by 5.2 mm (XGA resolution, 1024 x 768 pixel)
- pixel size in focus plane: 4 x 4 µm
- exposure times: > 6 ms per frame
- typical wavelength range: 280nm to 400nm
Partners:
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