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Développement d'un microscope à grande profondeur de champ pour l'imagerie fonctionnelle de neurones dans des échantillons épais
| Content Provider | Semantic Scholar |
|---|---|
| Author | Thériault, Gabrielle |
| Copyright Year | 2015 |
| Abstract | One of the greatest challenges of modern neuroscience that will lead to a better understanding and earlier diagnostics of brain sickness is to decipher the details of neuronal interactions in the living brain. To achieve this goal, we must be capable of observing populations of living cells in their original matrix with a good resolution, both spatial and temporal. Two-photon microscopy offers the right tools for this since it presents with a spatial resolution in the order of the micron. Unfortunately, this very good three-dimensional resolution lowers the temporal resolution because the optical sectioning caused by the microscope’s small depth of field forces us to scan thick samples repeatedly when acquiring data from a large volume. In this doctoral project, we have designed, built and characterized a two-photon microscope with an extended depth of field with the goal of simplifying the functional imaging of neurons in thick samples. To increase the laser scanning microscope’s depth of field, we shaped the laser beam entering the optical system in such a way that a needle of light is generated inside the sample instead of a spot. We modify the laser beam with an axicon, a cone-shaped lens that transforms a gaussian beam into a quasi non-diffractive beam called Bessel-Gauss beam. The excitation beam therefore maintains the same transverse resolution at different depths inside the sample, eliminating the need for many scans in order to probe the entire volume of interest. In this thesis, we demonstrate that the extended depth of field microscope effectively works as we designed it, and we use it to image calcium dynamics in a three-dimensional network of live neurons. We also present the different advantages of our system in comparison with standard two-photon microscopy. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://corpus.ulaval.ca/jspui/bitstream/20.500.11794/25740/1/31323.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
