Deep-Tissue Optical Activation, Stimulation & Imaging System
The OASIS Implant, developed and produced by Mightex Systems, couples with a small implantable lens to enable the user to do imaging and patterned optical stimulation at any depth in brain tissue of behaving or anaesthetized animals.
How it works – GRIN lens implant and fiber coupling
This is achieved by coupling one end of a fiber bundle, containing an array of thousands of micro fibers, with an implanted GRIN lens. The other end of the fiber array bundle is coupled into the OASIS Implant platform, which accommodates the illumination and detection devices, as well as the filters and mirrors for directing outgoing and incoming light (see diagram below).
The GRIN lens supplied with the system is 500μm in diameter and 7mm in length (alternative dimensions available). Variations in depth of the implant enables you to address different structures and layers in the brain.
A fiber mount is fixed to the skull, just above the GRIN lens. This mount provides a stable structural interface between the fiber bundle and the GRIN lens. The fiber connection can be disengaged after each experiment, allowing for downtime between experiments and for experimenting on other animals using the same OASIS system.
The OASIS Platform, into which the other end of the fiber bundle couples, has two illumination ports, one or both of which can be connected to a Polygon400 spatial illuminator.
Spatial/Patterned illumination in vivo
The Polygon400 is a DMD-based patterned illuminator, which means it can project light down each fiber individually, allowing for complex spatial and temporal light patterns to be projected down the fiber tract.
The second port on the OASIS Implant Platform can be left empty, or it can be dedicated to a second Polygon400 or an LED Lightsource, allowing for great flexibility on the illumination end.
The detection side of the Implant Platform is equally flexible, since any c-mount CCD or sCMOS camera can be used for detection.
User-exchangeable filters and mirrors are also fitted in the Platform, and the lightpath can be adjusted mid-experiment using the three integrated filter sliders.
Types of Experiments
GCaMP6 imaging in the Striatum using the OASIS Implant with a 300um imaging fiber.
The light headmount required to use the OASIS implant enables a rodent to be freely-moving.
The OASIS Implant coupling to the GRIN lens is light-weight and robust enough to allow for recordings in freely behaving mouse, and it’s been proven to be the ideal tool for recording calcium signals in deep-tissue, using GCaMP6, for example.
The system is also ideal for photoactivation or photoinhibition of neurons in the space near the lens’ focal plane – this can be done in a targeted way by only illuminating certain subsections of the field of view.
Because you have complete freedom with the illumination wavelength combination, and the additional benefit of using the patterned illumination, the system offers plenty of scope for other experiments, especially with the fast pace of development in the range and efficiency of opsins, fluorescent reporters and dyes.
This versatility is increased by the fact that you can use any camera for detecting the emitted light. This means that fast signals or low intensity signals are measurable, and you can use your preferred imaging software or the Mightex PolyScan software for acquisition and online analysis.
Benefits of the OASIS implantable fiber system:
Please visit the Mightex Systems website to find more information about the OASIS Implantable Fiber System.