0000000000223248
AUTHOR
Francesco Vanzi
showing 11 related works from this author
Direct activation of zebrafish neurons by ultrasonic stimulation revealed by whole CNS calcium imaging
2020
Abstract Objective. Ultrasounds (US) use in neural engineering is so far mainly limited to ablation through high intensity focused ultrasound, but interesting preliminary results show that low intensity low frequency ultrasound could be used instead to modulate neural activity. However, the extent of this modulatory ability of US is still unclear, as in in vivo studies it is hard to disentangle the contribution to neural responses of direct activation of the neuron by US stimulation and indirect activation due either to sensory response to mechanical stimulation associated to US, or to propagation of activity from neighboring areas. Here, we aim to show how to separate the three effects and…
Power-effective scanning with AODs for 3D optogenic applications
2022
Two-photon (2P) excitation is a cornerstone approach widely employed in neuroscience microscopy for deep optical access and sub-micrometric-resolution light targeting into the brain. However, besides structural and functional imaging, 2P optogenetic stimulations are less routinary, especially in 3D. This is because of the adopted scanning systems, often feebly effective, slow and mechanically constricted. Faster illumination can be achieved through acousto-optic deflectors (AODs) although their applicability to large volumes excitation has been limited by large efficiency drop along the optical axis. Here, we present a new AOD-based scheme for 2P 3D scanning that improves the power delivery…
Two-photon light-sheet microscopy for high-speed whole-brain functional imaging of zebrafish neuronal physiology and pathology
2020
We present the development of a custom-made two-photon light-sheet microscope optimized for high-speed (5 Hz) volumetric imaging of zebrafish larval brain for the analysis of neuronal physiological and pathological activity. High-speed volumetric two-photon light-sheet microscopy is challenging to achieve, due to constrains on the signal-to-noise ratio. To maximize this parameter, we optimized our setup for high peak power of excitation light, while finely controlling its polarization, and we implemented remote scanning of the focal plane to record without disturbing the sample. Two-photon illumination is advantageous for zebrafish larva studies since infra-red excitation does not induce a …
Fast whole-brain imaging of seizures in zebrafish larvae by two-photon light-sheet microscopy
2022
Light-sheet fluorescence microscopy (LSFM) enables real-time whole-brain functional imaging in zebrafish larvae. Conventional one photon LSFM can however induce undesirable visual stimulation due to the use of visible excitation light. The use of two-photon (2P) excitation, employing near-infrared invisible light, provides unbiased investigation of neuronal circuit dynamics. However, due to the low efficiency of the 2P absorption process, the imaging speed of this technique is typically limited by the signal-to-noise-ratio. Here, we describe a 2P LSFM setup designed for non-invasive imaging that enables quintuplicating state-of-the-art volumetric acquisition rate of the larval zebrafish bra…
Dual-beam confocal light-sheet microscopy via flexible acousto-optic deflector
2019
Confocal detection in digital scanned laser light-sheet fluorescence microscopy (DSLM) has been established as a gold standard method to improve image quality. The selective line detection of a complementary metal-oxide-semiconductor camera (CMOS) working in rolling shutter mode allows the rejection of out-of-focus and scattered light, thus reducing background signal during image formation. Most modern CMOS have two rolling shutters, but usually only a single illuminating beam is used, halving the maximum obtainable frame rate. We report on the capability to recover the full image acquisition rate via dual confocal DSLM by using an acoustooptic deflector. Such a simple solution enables us t…
Two-photon high-speed light-sheet volumetric imaging of brain activity during sleep in zebrafish larvae
2020
Although it is well known that zebrafish display the behavioural signature of sleep, the neuronal correlates of this state are not yet completely understood, due to the complexity of the measurements required. For example, when performed with visible excitation light, functional imaging can disrupt the day/night cycle due to the induced visual stimulation. To address this issue, we developed a custom-made two-photon light-sheet microscope optimized for high-speed volumetric imaging. By employing infra-red light (not visible to the larva) for excitation, we are able to record wholebrain neuronal activity with high temporal- and spatial-resolution without affecting the sleep state. In two-pho…
Flexible multi-beam light-sheet fluorescence microscope for live imaging without striping artifacts
2018
The development of light-sheet fluorescence microscopy (LSFM) has greatly expanded the experimental capabilities in many biological and biomedical research fields, enabling for example live studies of murine and zebrafish neural activity or of cell growth and division. The key feature of the method is the selective illumination of a sample single plane, providing an intrinsic optical sectioning and allowing direct 2D image recording. On the other hand, this excitation scheme is more affected by absorption or scattering artifacts in comparison to point scanning methods, leading to un-even illumination. We present here an easily implementable method, based on acousto-optical deflectors (AOD),…
Visualization_1
2022
Volumetric recording of a single CRIW event shown as a selected subset of coronal sections. To produce the time lapse, original 16-bit depth images were converted into 8-bit and JPEG compressed. Scale bar: 100 ��m.
Visualization_2
2022
3D rendering of the lag map shown in Fig. 4a. The lag value is color-coded as specified by the color bar. Scale bar: 100 ��m.
Visualization_1
2022
Volumetric recording of a single CRIW event shown as a selected subset of coronal sections. To produce the time lapse, original 16-bit depth images were converted into 8-bit and JPEG compressed. Scale bar: 100 ��m.
Visualization_2
2022
3D rendering of the lag map shown in Fig. 4a. The lag value is color-coded as specified by the color bar. Scale bar: 100 ��m.