Objective. We propose a closed-loop transcranial ultrasound stimulation (TUS) with a fuzzy controller to realize real-time and precise control of the motor response and neural activity of mice. Approach. The mean absolute value (MAV) of the electromyogram (EMG) and peak value (PV) of the local field potential (LFP) were measured under different ultrasound intensities. A model comprising the characteristics of the MAV of the EMG, PV of the LFP, and ultrasound intensity was built using a neural network, and a fuzzy controller, PID controller, and immune feedback controller were proposed to adjust the ultrasound intensity using the feedback of the EMG MAV and the LFP PV. Main results. In simulation, the quantitative calculation indicated that the maximum relative errors between the simulated EMG MAV and the expected values were 17%(fuzzy controller), 110% (PID control), 66% (immune feedback control); furthermore, the corresponding values of the LFP PV were 12%(fuzzy controller), 53% (PID control), 55% (immune feedback control). The average relative errors of fuzzy controller, PID control, immune feedback control were 4.97%, 13.15%, 11.52 %, in the EMG closed-loop experiment and 7.76%, 11.84 %, 13.56%, in the LFP closed-loop experiment. Significance. The simulation and experimental results demonstrate that the closed-loop TUS with a fuzzy controller can realize the tracking control of the motor response and neural activity of mice.

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In this paper, we proposed a chemical-gas fiber sensor based on the poly-aniline film coated on the surface of an etched fiber grating and experimentally demonstrated for detecting ammonia gas. This sensing mechanism is based on the testing gas to interact with the poly-aniline coating film on the surface of the fiber grating to cause the thin-film index change and then to create the Bragg wavelength shift or grating reflectivity variation. The sensitivity and response time of this sensor for measuring ammonia gas are around 0.73 nm per percent concentration and tens of mini-seconds respectively, which depend on the optical characteristics of fiber grating, the diameter of fiber cladding, and the constituents of chemical sensing film. This sensor may provide a simple, reliable, repeatable and non-destructive fiber sensing technique.