Closed-loop recruitment of striatal parvalbumin interneurons prevents the onset of compulsive behaviors

A prominent electrophysiological feature of compulsive behaviours is striatal hyperactivity; but its underlying dysfunctional cellular mechanisms still need to be characterized. Within the striatum, parvalbumin-positive interneurons (PVI) exert a powerful feedforward inhibition essential for the regulation of striatal activity. To investigate the potential implication of striatal PVI in aberrant repetitive behaviors, we used the Sapap3 mutant mice which exhibit compulsive-like behaviours characterized by excessive self-grooming. When striatal PVI in the centromedial striatum of Sapap3 mice were we optogenetically activated, we first showed that the number of compulsive-like events were greatly reduced. To investigate further the critical time-window when striatal PVI needed to be recruited for the behavioural regulation of compulsive-like grooming, we then designed a novel closed-loop stimulation pipeline. We identified a transient 1-4 Hz oscillations in the orbitofrontal cortex that temporally predicted grooming onsets. Exploiting this delta band signal as a biomarker, we were able to provide on-demand stimulation of striatal PVI shortly before predicted grooming events. This targeted closed-loop optogenetics approach greatly reduced grooming events and demonstrated that the recruitment of striatal PVI regulated the initiations of compulsive-like behaviours.

Dual-Band, Dual-Output Power Amplifier Using Simplified Three-Port, Frequency-Dividing Matching Network

This study presents a dual-band power amplifier (PA) with two output ports using a simplified three-port, frequency-dividing matching network. The dual-band, dual-output PA could amplify a dual-band signal with one transistor, and the diplexer-like output matching network (OMN) divided the two bands into different output ports. A structure consisting of a λ/4 open stub and a λ/4 transmission line was applied to restrain undesired signals, which made each branch equivalent to an open circuit at another frequency. A three-stub design reduced the complexity of the OMN. Second-order harmonic impedances were tuned for better efficiency. The PA was designed with a 10-W gallium nitride high electron mobility transistor (GaN HEMT). It achieved a drain efficiency (DE) of 55.84% and 53.77%, with the corresponding output power of 40.22 and 40.77 dBm at 3.5 and 5.0 GHz, respectively. The 40%-DE bandwidths were over 200 MHz in the two bands.

Frequency domain of weakly translation invariant frame MRAs

Frequency domain of bandlimited frame multiresolution analyses (MRAs) plays a key role when derived framelets are applied into narrow-band signal processing and data analysis. In this study, we give a characterization of frequency domain of weakly translation invariant frame scaling functions [Formula: see text] with frequency domain [Formula: see text]. Based on it, we further study convex and ball-shaped frequency domains. If frequency domain of bandlimited frame scaling function [Formula: see text] is convex and completely symmetric about the origin, then it must be weakly invariant and [Formula: see text]. If [Formula: see text] has a ball-shaped frequency domain, the ball radius must be bounded by [Formula: see text]. These frequency domain characters are owned uniquely by frame scaling functions and not by orthogonal scaling functions.

Neurodevelopmental Preparedness for Language in the Neonatal Brain

Neonates show broad-based, universal speech perception abilities, allowing them to acquire any language. Moreover, an increasing body of research shows that prenatal experience with speech, which is a low-pass signal mainly preserving prosody, already shapes those abilities. In this review, we first provide a summary of the empirical evidence available today on newborns’ universal and experience-modulated speech perception abilities. We then interpret these findings in a new framework, focusing on the role of the prenatal prosodic experience in speech perception development. We argue that the chronological sequence of infants’ experience with speech, starting before birth with a low-pass filtered signal and continuing with the full-band signal after birth, sets up the prosodic hierarchy and a cascade of embedded neural oscillations as its brain correlate, laying the foundations for language acquisition. Prosody, constituting infants’ very first experience with language, may thus play a fundamental role in speech perception and language development.

Compact, Reflectionless Band-Pass Filter: Based on GaAs IPD Process for Highly Reliable Communication

For highly reliable and compact communication of front-end modules, a miniaturized reflectionless band-pass filter, based on the GaAs integrated passive device (IPD) process, is proposed in this work. The stop-band signal absorption rate of the filter can reach more than 90% and greatly reduce the influence of electromagnetic interference for sensitive devices. First, a circuit topology of reflectionless filter is proposed. Then, the miniaturized reflectionless band-pass filter is designed and fabricated based on GaAs IPD process with a compact size of only 0.85 mm × 1.33 mm × 0.09 mm (0.011λ × 0.018λ × 0.001λ). The filter operates at frequency ranging from 3.3 GHz to 4.5 GHz for 5G communication, the insertion loss (S21) is less than 3 dB, the return loss in the passband (S11) is over 15 dB, the stopband return loss (S11) is over 10 dB, and the out-of-band suppression (S21) reached 19 dB. All the measured results are in good agreement with the simulated results. It shows great potential in the process of designing highly reliable and compact monolithic integrated wireless modules and wearable electronics.

Sub-band detection of small-sized objects during airspace sensing with ultra-short radio pulses

The possibility of ensuring the safety of flights of aircraft, such as helicopters, at low altitudes, where there is a high probability of unauthorized appearance of small-sized objects such as unmanned aerial vehicles, is being considered. The possibility of solving the problem of detecting such objects on the basis of radar soundings in the resonant frequency range of the UHF radio wave range is considered. Sub-band processing of the received signals is proposed, based on the division of the spectral definition area into sub-bands, for adaptation to the frequency response band and noise filtering. The mathematical apparatus of sub-band signal analysis using sub-band matrices has been developed. An optimal solution to the problem of filtering responses in given sub-bands is obtained. A procedure for processing the received signals is given when making decisions about the presence of a response in a given sub-band. Estimates of the probabilities of erroneous decisions are given for a given probability of errors of the first kind.

A Low Complexity Non-Distortion Clipping Technique PAPR Reduction of MIMO-OFDM Systems

Amplitude clipping is one of the techniques used to reduce PAPR. This technique does not demand side information; therefore, there is no reduction in the system's data throughput. However, it leads to additional distortion (in-band signal distortion and out-of-band radiation). To overcome this problem, low complexity non-distortion clipping technique is proposed for MIMO-OFDM system. The main concept of this proposed method is how to convert the generated distortion (in-band and out-of-band signals distortion) when using clipping at transmitter to impulse noise (error), which is possible by using a simple coding technique to cover error at the receiver. The proposed method does not clip the signal in time domain. The clipping use for discrete samples directly after IFFT. Simulation outcome detects that the proposed non-distortion clipping technique provides an efficient reduction in PAPR, best performance compared with conventional clipping technique, and less cost and complexity.