Multiphoton imaging system

Description du marché

The research group of Stefanos Stagkourakis will carry out a project focused on all-optical investigations that provide the capability of imaging and manipulating neuronal activity at the same time. Specifically, multiphoton imaging of Ca2+ and voltage indicators will be used to study neuron activity on large neuron populations in vivo and in vitro. Successful pursuit of this work requires simultaneous recording of activity and manipulation through multiphoton photostimulation of pre-selected neuron ensembles to study a causal role of specific neuron subpopulations in behavior. A key component of the project is complementing the head-fixed in vivo neural activity and ensemble manipulation recordings with neuron activity imaging in freely moving animals through the Inscopix miniscope technology. In order to be able to carry out the research, KI needs to purchase an Multiphoton imaging system that meets the following requirements: a. The system must have a volumetric imaging solution which is decoupled from the photostimulation pathway while still offering a travel range that will allow imaging between planes of interest that are spatially separated by at least 390um in Z. This is needed to allow imaging and interrogation of the areas of interest across layers. Without that level of travel, simultaneous imaging and stimulation at multiple planes of interest would not possible where they are needed. Decoupling the photostimulation and imaging beams is necessary otherwise biological temporal resolution will not be observed due to the delay between stimulating, refocusing and imaging. b. The system must have a Spatial Light Modulator (SLM) to produce an axial resolution no larger than 10um. This is necessary to ensure that only the cells of interest are stimulated. Stimulation of multiple cells throughout a 3D volume is a key part of the project. If the axial resolution is larger than 10um, there is a risk that multiple cell layers can be stimulated instead of it being limited to the areas of interest c. It’s important that the objective of the system can be rotated, without sacrificing the SLM resolution, excitation, or collection efficiency. This is necessary when undertaking behavioral experiments as tilting the animal can cause it to behave unnaturally, a variable which is difficult to account for and one which can compromise the scientific integrity of the experiment itself. Maintaining this integrity should not come at the expense of signal otherwise power would need to be increased, causing unnecessary distress to the animal and a further experimental variable. d. The system must have detectors that are physically protected from any transmitted lightused for the imaging of brain slices. There must be a protection circuit in place that willnot allow any multiphoton detection to occur while the transmitted light source isactive. e. The research involves correlative studies between head-fixed and freely moving mouse models. Having access to a cloud-based software platform that can incorporate both data types is necessary as it enables faster, more efficient batch processing of computationally intense features. f. The system must be able to image and stimulate independently throughout the whole volume of a brain slice (up to 300µm depth) with a switching speed between planes of around 15ms. This speed and depth combination is especially valuable for capturing dynamic processes in 3D and for stimulating specific preselected brain populations with temporal precision. To KI’s knowledge there is no other supplier that offers a setup with proven equivalent functions. KI will sign a contract with Bruker after a standstill period of 10 days after publishing this Voluntary ex ante transparency notice.

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