Biology subjects

Maglie, E.

Publications and source records attributed to Maglie, E..

3 recordsLinked to original sources

bioRxiv2020

Ray tracing models for estimating light collection properties of microstructured tapered optical fibers for optical neural interfaces

Tapered optical fibers (TFs) were recently employed for depth-resolved monitoring of functional fluorescence in sub-cortical brain structures, enabling light collection from groups of a few cells through small optical windows located on the taper edge [1]. Here we present a numerical model to estimate light collection properties of microstructured TFs implanted in scattering brain tissue. Ray tracing coupled with Henyey-Greenstein scattering model enables the estimation of both light collection and fluorescence excitation fields in three dimensions, whose combination is employed to retrieve the volume of tissue probed by the device.

bioengineering↗

bioRxiv2018

Multipoint and large volume fiber photometry with a single tapered optical fiber implant

Techniques to monitor functional fluorescence signal from the brain are increasingly popular in the neuroscience community. However, most implementations are based on flat cleaved optical fibers (FFs) that can only interface with shallow tissue volumes adjacent to the fiber opening. To circumvent this limitation, we exploit modal properties of tapered optical fibers (TFs) to structure light collection over the wide optically active area of the fiber taper, providing an approach to efficiently and selectively collect light from the region(s) of interest. While being less invasive than FFs, TF probes can uniformly collect light over up to 2 mm of tissue and allow for multisite photometry along the taper. Furthermore, by micro-structuring the non-planar surface of the fiber taper, collection volumes from TFs can also be engineered arbitrarily in both shape and size. Owing to the abilities offered by these probes, we envision that TFs can set a novel, powerful paradigm in optically targeting not only the deep brain, but, more in general, any biological system or organ where light collection from the deep tissues is beneficial but challenging because of tissue scattering and absorption.

neuroscience↗

bioRxiv2017

Exploiting modal demultiplexing properties of tapered optical fibers for tailored optogenetic stimulation

Optogenetic control of neural activity in deep brain regions requires precise and flexible light delivery with non-invasive devices. To this end, Tapered Optical Fibers (TFs) represent a minimally-invasive tool that can deliver light over either large brain volumes or spatially confined subregions. This work links the emission properties of TFs with the modal content injected into the fiber, finding that the maximum transversal propagation constant (kt) and the total number of guided modes sustained by the waveguide are key parameters for engineering the mode demultiplexing properties of TFs. Intrinsic features of the optical fiber (numerical aperture and core/cladding diameter) define the optically active segment of the taper (up to [~]3mm), along which a linear relation between the propagating set of kt values and the emission position exists. These site-selective light-delivery properties are preserved at multiple wavelengths, further extending the range of applications expected for tapered fibers for optical control of neural activity.

neuroscience↗