Biology subjects

Sileo, L.

Publications and source records attributed to Sileo, L..

2 recordsLinked to original sources

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↗

bioRxiv2016

Dynamically controlled light delivery over large brain volumes through tapered optical fibers

Optogenetics promises spatiotemporal precise control of neural processes using light. However, the spatial extent of illumination within the brain is difficult to control and cannot be adjusted using standard fiber optics. We demonstrate that optical fibers with tapered tips can be used to illuminate either large brain volumes or dynamically selectable subregions. Remotely adjusting the light input angle to the fiber varies the light-emitting portion of the taper over several millimeters without movement of the implant. We use this mode to activate dorsal versus ventral striatum of individual mice and reveal different effects of each manipulation on motor behavior. Conversely injecting light over the full numerical aperture of the fiber results in light emission from the entire taper surface, achieving broader and more efficient optogenetic activation of neurons when compared to the standard flat-faced fiber stimulation. Thus, tapered fibers permit focal or broad illumination that can be precisely and dynamically matched to experimental needs.

neuroscience↗