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Main address: www.au.dk

Femtosecond Tunable Laser

Describe briefly the project. There is little dispute that synaptic plasticity is the foundation for learning and memory. For this reason, there has been an intense interest in understanding the signaling pathways underlying plasticity. However, until now, these studies have been mostly performed in brain slice preparations. As valuable as this approach is many stages in the life of a memory, such as its recall and loss must be monitored in behaving animals. To achieve this, we need a system with high spatial resolution down to the synaptic scale, where memories are formed and stored. The most promising approach is two-photon laser microscope (2PLSM) imaging in live animals, which allows monitoring the morphological changes that occur in synapses during various stages of memory formation and consolidation.

We will use 2PLSM imaging to monitor synaptic plasticity during memory formation and consolidation. Specifically, we will ask whether formation of an associative memory results.

Femtosecond tunable lasers have made imaging from deep regions of a brain tissue possible. In multiphoton microscopy, these lasers allow to image a broad range of fluorescent proteins from regions as deep as 600-700 micrometers. Despite their power, the ultrafast lasers come with limitations that reduce their effectiveness. For instance, in multiphoton microscopy, which a fluorophore is excited through simultaneous absorption of two photons, caused by high-pick intensity of ultrafast pulses, the efficiency of the process is rarely optimised. The physic behind this phenomenon, known as group-velocity dispersion (GVD) is that the ultrafast pulses pass through optical elements of the microscope, they become broadened. As such, this reduces the desired imaging depth.

InSight X3, a newly developed ultrafast laser by Spectra-Physics, has the property to avoid the problem of GVD. The technique, which is known as dispersion pre-compensation, achieves this by generates negative GVD by delaying long wavelengths compared to shorter ones. We looked at other suppliers of ultrafast lasers, but we did not find a vendor other than Spectra-Physics that provides this ability.

Femtosecond tunable lasers have made imaging from deep regions of a brain tissue possible. In multiphoton microscopy, these lasers allow to image a broad range of fluorescent proteins from regions as deep as 600-700 micrometers. Despite their power, the ultrafast lasers come with limitations that reduce their effectiveness. For instance, in multiphoton microscopy, which a fluorophore is excited through simultaneous absorption of two photons, caused by high-pick intensity of ultrafast pulses, the efficiency of the process is rarely optimised. The physic behind this phenomenon, known as group-velocity dispersion (GVD) is that the ultrafast pulses pass through optical elements of the microscope, they become broadened. As such, this reduces the desired imaging depth.

InSight X3, a newly developed ultrafast laser by Spectra-Physics, has the property to avoid the problem of GVD. The technique, which is known as dispersion pre-compensation, achieves this by generates negative GVD by delaying long wavelengths compared to shorter ones. We looked at other suppliers of ultrafast lasers, but we did not find a vendor other than Spectra-Physics that provides this ability.

Internet address:https://erhvervsstyrelsen.dk/klagenaevnet-for-udbud