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 spatially restricted or large brain volumes. 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.

A variety of voltammetric methods have been carried out for determination of brexpiprazole (BRX) using cyclic voltammetry (CV) and two different type anodic stripping methods; differential pulse (AS-DP) and square wave (AS-SWV) at modified carbon paste electrode with gold nanoparticles (AuNPs-CPEs). Additionally, electrochemical impedance spectroscopy (EIS) technique has been utilized for characterization of the different electrodes. Electrochemical oxidation behavior of BRX shows an irreversible anodic peak at 0.88 V versus Ag/AgCl, in Britton-Robinson buffer (BR) at pH 4.0, 50s preconcentration time and −0.5 deposition potential. Rectilinear relationship between the peak current versus concentration was obtained over the ranges of 1.32 × 10 −6 -6.45 × 10 −6 and 1.32 × 10 −7 -6.45 × 10 −7 mol L −1 for AS-DP and AS-SWV respectively. The lowest concentration that can be detected for both for AS-DP and AS-SWV was 3.99 × 10 −7 and 3.32 × 10 −8 mol L −1 respectively; the utilized methods have been devoted adequately for the estimation of BRX in its pure and dosage form.

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Optogenetics sets new experimental paradigms that can reveal cell type-specific contributions on the neural basis of behavior. Since most of the available systems for this purpose are based on approaches that tether animals to a set of cables, recent research activities have been focused on minimizing external factors that can alter animal movements. Current wireless optogenetic systems are based on waveguide-coupled LED and implanted LEDs. However, each configuration separately suffers from significant limitations, such as low coupling efficiency, penetration depth and invasiveness of waveguide-coupled LED, and local heat generated by implanted LEDs. This work presents a novel wireless head-mountable stimulating system for a widevolume light delivery. The device couples the output of a semiconductor laser diode (LD) to a tapered optical fiber (TF) on a wireless platform. The LD-TF coupling was engineered by setting up far-field analysis, which allows a full exploitation of mode division demultiplexing properties of TFs. The output delivered light along the tapered segment is capable of stimulating structures of depths up to ~2mm. TFs are tapered to a gradual taper angle (Ψ~2° to Ψ~10°) that ends with a sharp tip (~500 nm) for smooth insertion and less invasiveness. Thus, the proposed system extends the capabilities of wireless optogenetic by offering a novel solution for wide volume light delivery in deep brain regions.