Differential Input Research Articles

Morphological characterization of cholinergic partition cells: A transmitter-specific tracing study by Cre/lox-dependent viral gene expression

BackgroundPartition cells are cholinergic interneurons located in lamina VII of the spinal cord. Some partition cells are the source of the cholinergic boutons, known as C-terminals or C-boutons, that modulate the activity of spinal motor neurons. Therefore, partition cells might play an important role in motor control. Previous studies categorized partition cells into three groups (medial, intermediate, and lateral partition cells) according to their distance from the central canal. However, the morphological characteristics of the three groups remain obscure. MethodsTo analyze the morphology of partition cells, we developed an efficient technique for visualization of specific neurons at single-cell level in particular positions using adenovirus vectors and Cre/lox mediated recombination. Cre/lox conditional vectors were injected into the spinal cord of choline acetyltransferase-Cre transgenic mice, and partition cells labeled by green fluorescent protein were reconstructed from histological serial sections at the single-cell level. ResultsThis technique allowed for the visualization of partition cells at high resolution and revealed that partition cells had various patterns of dendrite orientations and fields. Most of the visualized partition cells had more than 60% of their dendrites located in lamina VII of the spinal cord. Partition cells had dendrites extending into various Rexed’s laminae (V, VI, VII, VIII, IX, and X), but none of the cells had dendrites extending dorsal to lamina IV. The dendrites of partition cells terminated both ipsilaterally and bilaterally. We also found that C-terminals on motor neurons may be derived from the middle/outer group of partition cells. ConclusionsOur results indicated that partition cells have various morphological features of the dendritic pattern and may receive differential inputs. Our results suggested that C-terminals originate not only from medial but also from intermediate/lateral cholinergic partition cells. The present study suggests that intermediate/lateral partition cells modulate activities of motor neurons through C-terminal synapses.

A Low Power SAR ADC with Digital Error Correction Technique for Wearable and Implantable ECG Devices

Aims: This study aims to propose an 8-bit differential input low-power Successi,e Approximation Register (SAR) ADC with digital error correction technique for sensing bio-potential signals in wearable and implantable devices. Background: As dynamic comparators have the advantages of full swing output, low power consumption, high speed, and high impedance at the input, they are preferably used in energy-efficient SAR ADC’s. However, since the dynamic comparator is the most frequently used block in SAR ADC, research is ongoing to reduce its μW power further. Also, as the offset voltage of the comparator affects the linearity of ADC, it must be minimized. Linearity can further be improved by calibrating the output of ADC, and extensive surveys on the calibration methods prove that the addition- only digital error correction method is efficient in terms of power. Objective: The objective of this study is to design a low-power and low-offset dynamic comparator intended for SAR ADC to achieve highly linear digital output. In addition to this, the objective is to implement a power-efficient digital error correction technique for the output of SAR ADC to overcome the non-idealities due to process variations. Method: As power consumption is proportional to the number of transistors, the proposed comparator is a design obtaining the same output as the existing dynamic comparators with reduced transistor count. The proposed comparator, along with low power full swing three-input XOR logic gate, is implemented in SAR ADC with digital error correction technique in cadence 45 nm technology files, and its performance parameters are simulated. Results: The layout of the proposed dynamic comparator occupies an area of 3 μm2. The simulation results of this comparator with a load of 1 pF show that it has a total offset of 11.2 mV, a delay of 0.9 ns, and power consumption of 24 nW. It also achieves a gain of 49.5, i.e., 33.86 dB. The 8-bit ADC, along with the digital error correction technique operating at 143-kS/s and under 0.6 V supply voltage simulated in 45nm technology, consumes only 0.12 μW of power. The DNL and INL errors obtained are +0.22/-0.2 LSB and -0.28 LSB, respectively. SNR limited by noise is 48.25 dB, SFDR is 48.64 dB, and ENOB achieved is 7.72. Conclusion: To satisfy the requirement of the wearable and implantable devices, a low-power SAR ADC with good linearity is designed using a low-power and low-offset dynamic comparator. A digital error correction technique using a low-power XOR logic gate is implemented at the SAR ADC output to minimize the non-idealities due to the process variations.

Electronically and Orthogonally Tunable SITO Voltage-Mode Multifunction Biquad Filter Using LT1228s

The commercially available IC LT1228 is an interesting active device due to its advantage features, such as a fast transconductance amplifier, a wide bandwidth over a wide range of voltage gain, low total harmonic distortion (THD), high impedance differential input, etc. The single-input triple-output (SITO) voltage-mode (VM) multifunction biquadratic filters using ICs, LT1228s are introduced in this research. This circuit design provides the three-filtering functions, low-pass (LP), high-pass (HP), and band-pass (BP), without changing the circuit architecture. It comprises three LT1228s, four resistors, and two capacitors connected to the ground. The low impedance voltage output nodes are HP and BP responses. The quality factor (Q) and the pole frequency (ω0) can be electronically and orthogonally tuned by altering the third LT1228’s bias current (IB). The PSPICE simulation and the experiment are verified to describe the circuit operation.

A 12.1bit-ENOB noise shaping SAR ADC for biosensor applications

This paper proposes a low power fully-passive noise shaping successive approximation register analog-to-digital converter (SAR ADC) for biosensor applications. The proposed ADC includes a second-order fully-passive integrator achieves a second-order noise transfer function. With an independent residue voltage generator to adjust common voltage between the main and residue path, the power efficiency of three differential inputs comparator is improved. The 0.18μm CMOS prototype chip occupies a total area of 1.37 mm2 with a core area of 0.58 mm2 and consumes 131 μW from a 1.3 V supply. The proposed SAR ADC achieves a peak signal-to-noise-and-distortion ratio (SNDR) of 74.8 dB and a peak spurious-free dynamic range (SFDR) of 89.7 dB at a sampling rate of 8 MSPS and oversampling rate of 16, leading to the Schreier figure of merit (FoMs) of the proposed ADC of 167.4 dB.

Comparative Analysis of CNTFET Models through the Design of a Differential Amplifier

In this paper we compare simulation results on a differential pair circuit using a CNTFET model, already proposed by us, with the result obtained using Stanford model. We study the case of differential pair with differential input and single ended output as core of a 50 GHz amplifier for mm waves band. We consider the case of a CNTFET having a single CNT tube with indices (19,0) and 25 nm long. For this circuit we present result for its main parameters: gain, input impedance, output impedance, noise and distortion. Since the Stanford model includes fixed capacitance, for comparison we applied the same capacitance on our model. Since this capacitances dominate the high frequency cut, results are not much different, except for the lack of noise modelling in the Stanford model.

Organochlorine pesticides and chlorpyrifos in the sea anemone Bunodosoma zamponii (Actiniaria: Actiniidae) from Argentina's southeastern coast

Temporal and spatial distribution of organochlorine pesticides (OCPs) and the organophosphate pesticide chlorpyrifos, one of the main insecticides used in Argentina, was evaluated in two populations of the sea anemone Bunodosoma zamponii living under different anthropological stressors: Las Delicias (LD) adjacent to a wastewater plant, and Punta Cantera (PC) a reference site. Pesticides were analyzed throughout the year in water, sediments and whole organisms. Chlorpyrifos represented 50% of the total pesticide found in water samples during winter. HCHs and drins were predominant in sediment samples, mainly in LD. Total pesticide concentration in anemones from LD was higher than those from PC during winter (mainly associated with HCHs, endosulfans, DDTs and chlorpyrifos levels), coincident with the main period of effluent discharge to the coast after pesticide applications and also the rainiest season. Dissimilarities among anemones populations could stem from a differential input of pesticides in each site and/or a contrasting physiological status of the populations.

75–86-GHz Signal Generation Using a Phase-Controlled Quadrature-Push Quadrupler Driven by a QVCO or a Tunable Polyphase Filter

This article demonstrates a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$W$ </tex-math></inline-formula> -band local-oscillator generation technique in 120-nm SiGe BiCMOS technology with high output power and high efficiency. The circuit employs a frequency quadrupler that is driven with differential quadrature inputs that are provided by either a quadrature voltage-controlled oscillator (QVCO) or a tunable active polyphase filter (PPF) circuit. The quadrupler employs a phase-controlled quadrature-push (PCQP) topology using stacked devices with a lower class-C common-emitter (CE) amplifier generating a current that is then modulated by an upper common-base (CB) amplifier driven out-of-phase with the lower devices. Such a structure generates a strong fourth-order harmonic. Four such stacks driven at their input using accurate differential quadrature signals increase the fourth-harmonic output power while suppressing other harmonics. The differential quadrature signals for the quadrupler are provided using either a PPF circuit or a capacitive injection-locking QVCO, which achieves wide tuning range and low phase noise. Both approaches are evaluated through the measurement of separate test circuits. The LO circuit using the QVCO provides 8–11.5-dBm output power over 75.2–83 GHz, power efficiency of 2.2–4.1%, including QVCO and buffer power, >20-dB harmonic rejection in the lower frequency range, and >14.4-dB harmonic rejection in the upper frequency range. The LO circuit using the active PPF provides 8.4–11.2-dBm output power over 75.6–82.8 GHz, power efficiency of 2.4–4.8%, including PPF and buffer power, and >23-dB harmonic rejection.

A low-cost digital delay line for bat biosonar research

Bat biosonar research and bat neuroscience as a whole relies heavily on experiments to determine bat responses to various stimuli. Typically, these are presented to the bat using real world targets such prey insects, but also via artificial stimuli using an ultrasonic loudspeaker. One key component of artificial target creation is the use of delay lines. Analog delay lines have been used for decades to generate artificial targets at programmable ranges. More recently, digital delay lines have become the norm. This talk will present the details of the development of a very low-cost digital delay line that can produce bat echoes with up to three glints. The main delay between the bat and the target as well as the inter-glint spacing are programmable with delays as small as 5 μ s possible. The platform used is a commonly available SAMD51 microcontroller with a total system cost under $50. The talk will present experimental results, code development using commonly available programming tools, and schematics for an add-on board that uses microphone or general differential inputs. Finally, the talk will introduce an approach implement wideband Doppler shift (time-scaling) of digitally delayed echoes using direct memory access tools native to the SAMD51 microcontroller.

Evidence for two distinct thalamocortical circuits in retrosplenial cortex

Retrosplenial cortex (RSC) lies at the interface between sensory and cognitive networks in the brain and mediates between these, although it is not yet known how. It has two distinct subregions, granular (gRSC) and dysgranular (dRSC). The present study investigated how these subregions differ with respect to their electrophysiology and thalamic connectivity, as a step towards understanding their functions. The gRSC is more closely connected to the hippocampal formation, in which theta-band local field potential oscillations are prominent. We, therefore, compared theta-rhythmic single-unit activity between the two RSC subregions and found, mostly in gRSC, a subpopulation of non-directional cells with spiking activity strongly entrained by theta oscillations, suggesting a stronger coupling of gRSC to the hippocampal system. We then used retrograde tracers to test for differential inputs to RSC from the anteroventral thalamus (AV). We found that gRSC and dRSC differ in their afferents from two AV subfields: dorsomedial (AVDM) and ventrolateral (AVVL). Specifically: (1) as a whole AV projects more strongly to gRSC; (2) AVVL targets both gRSC and dRSC, while AVDM provides a selective projection to gRSC, (3) the gRSC projection is layer-specific: AVDM targets specifically gRSC superficial layers. These same AV projections are topographically organized with ventral AV neurons innervating rostral RSC and dorsal AV neurons innervating caudal RSC. These combined results suggest the existence of two distinct but interacting RSC subcircuits: one connecting AVDM to gRSC that may comprise part of the cognitive hippocampal system, and the other connecting AVVL to both RSC regions that may link hippocampal and perceptual regions. We suggest that these subcircuits are distinct to allow for differential weighting during integration of converging sensory and cognitive computations: an integration that may take place in thalamus, RSC, or both.

Differential-to-differential and single-ended-to-differential bandpass filters for 5G applications

This paper presents the design and implementation of bandpass filters for millimeter-wave (mm-Wave) applications. The filter structures are based on transmission line hybrid T-resonators and consist of differential input, differential output (DIDO) and differential/single-ended input, single-ended/differential output (DISO/SIDO) configurations. A prototype from each configuration is designed and fabricated using a microstrip substrate. In addition to good agreement with the simulation results, the measurement results of the fabricated prototypes exhibit higher selectivity, common-mode (CM) suppression and upper stopband attenuation compared to the state-of-the-art balanced filters, rendering the proposed concept suitable for the fifth generation (5G) telecommunication applications. Besides, this work presents the first reported balanced microstrip bandpass filter based on printed circuit board (PCB) at mm-Wave frequencies.

Mixed-mode Method Used for Pt100 Static Transfer Function Linearization

Abstract Pt100 is a resistance temperature detector characterized by a relatively linear resistance/temperature relationship in a narrow temperature range. However, the Pt100 sensor shows a certain degree of static transfer function nonlinearity of 4.42 % in the range between −200 °C and 850 °C, which is unacceptable for some applications. As a solution to this problem, a mixed-mode linearization method based on a special dual-stage piecewise linear ADC design is proposed in this paper. The first stage of the proposed dual-stage piecewise linear ADC is performed with a low-complex and low-power flash ADC of a novel sequential design. The novelty of the proposed sequential design is reflected in the fact that the number of employed comparators is equal to the flash ADC resolution. The second stage is performed with a delta-sigma ADC with a differential input and differential reference. Using the 6-bit flash ADC of novel design and the 24-bit delta-sigma ADC, the nonlinearity error is reduced to 2.6·10−3 %, in the range between −200 °C and 850 °C. Two more ranges are examined, and the following results are obtained: in the range between 0 °C and 500 °C, the nonlinearity error is reduced from 1.99 % to 5·10−4 %, while in the range between −50 °C and 150 °C, the nonlinearity error is reduced from 0.755 % to 2.15·10−4 %.

L-Lactate: Food for Thoughts, Memory and Behavior

More and more evidence shows how brain energy metabolism is the linkage between physiological and morphological synaptic plasticity and memory consolidation. Different types of memory are associated with differential inputs, each with specific inputs that are upstream diverse molecular cascades depending on the receptor activity. No matter how heterogeneous the response is, energy availability represents the lowest common denominator since all these mechanisms are energy consuming and the brain networks adapt their performance accordingly. Astrocytes exert a primary role in this sense by acting as an energy buffer; glycogen granules, a mechanism to store glucose, are redistributed at glance and conveyed to neurons via the Astrocyte–Neuron Lactate Shuttle (ANLS). Here, we review how different types of memory relate to the mechanisms of energy delivery in the brain.

Body Biased Sense Amplifier With Auto-Offset Mitigation for Low-Voltage SRAMs

This paper proposes a Differential-Input Body Bias Sense Amplifier (DIBBSA) with an auto-offset mitigation feature suitable for low-voltage SRAMs where the differential bitline signals are applied to the sources as well as to the body of the critical sensing transistors. We simulated and fabricated the proposed DIBBSA architecture with various operational modes in 65-nm CMOS technology to analyze body biasing's effectiveness in mitigating the offset. The standard deviation of offset ( σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OS</sub> ) was measured over 5120 SAs in 10 ICs. The iso-gate area reduction in σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OS</sub> for the proposed DIBBSA-FL and DIBBSA-PD modes resulted in 68.1% and 61.9% compared to conventional Current Latch SA (CLSA) and 24.1% and 18.1% compared to Voltage Latch SA (VLSA) at 0.4 V supply and 25 °C, respectively. Carried out measurements on 512 SAs in an IC show the minimum required differential input voltage across the temperature range of 0 °C to 75 °C at 0.4 V is achieved to be 48% lower compared to CLSA and 28% lower compared to VLSA by both the DIBBSA-FL and DIBBSA-PD modes.

A Novel Architecture for 10-bit 40MSPS Low Power Pipelined ADC Using a Simultaneous Capacitor and Op-amp Sharing Technique

This work presents a low-power 10-bit 40 MSPS Pipelined ADC with 1.8V supply voltage in a 180nm silicon-based CMOS process. Simultaneous capacitor sharing and op-amp sharing technique is used between two successive stages of a Sample-and-Hold Amplifier (SHA) to reduce the power consumption. The memory effect in the proposed ADC is eliminated by a low input capacitance variable gm op-amp. The differential and integral nonlinearity of the converter is within LSB. Simulation results show that the required Signal-Furious-Dynamic range (SFDR) of 70dB, Signal-to -Noise-plus Distortion Ratio (SNDR) of 56.1dB and 9.02 Effective Number of Bits ( ENOB ) has been achieved with a 2 MHz, 1-Vp−p, diff input signal while consuming only 7.3mW power from 1.8V supply.

Transient Subplate Sublayer Forms Unique Corridor for Differential Ingrowth of Associative Pulvinar and Primary Visual Projection in the Prospective Visual Cortical Areas of the Human Fetal Occipital Lobe.

Cytoarchitectonical parcellation of the visual cortex into the striate and extrastriate cortex requires complex histogenetic events within a precise spatio-temporal frame to attain the specification of areal domains and associated thalamocortical connections during the fetal brain development. We analyzed a deep subplate cellular monolayer (subplate "corridor" cells) present during a restricted period of 13-15 postconceptional weeks, showing the 3D caudo-ventro-medial position in the human fetal occipital lobe, corresponding to the segregation point of pulvinocortical and geniculocortical fibers at the prospective area 17/18 border. Immunofluorescence stainings revealed subplate "corridor" cells as the specific class of the deepest subplate neurons (NeuN+, Tbr1+, Cplx3+) expressing axon guidance molecules (Sema-3A+, EphA6+), presumably for the attraction of pulvinocortical axons and the repulsion of geniculocortical axons growing at that time (SNAP25+, Syn+, FN+). Furthermore, quantitative analysis of the subplate "corridor" region of interest, considering cell number, immunofluorescence signal intensity per cell and per region, revealed significant differences to other regions across the tangential circumference of the developing cerebral wall. Thus, our study sheds new light on the deepest subplate sublayer, strategically aligned along the growing axon systems in the prospective visual system, suggesting the establishment of the area 17/18 border by differential thalamocortical input during the fetal brain development.

Analysis and Design of a Microphone Preamplifier for Mobile Applications

A design of an on-chip ac-coupling preamplifier for mobile applications is presented. A microphone preamplifier should have a large input impedance to mitigate the effective-gain reduction caused by the microphone’s non-zero output impedance. From a review of previously reported microphone preamplifier structures in terms of input impedance, feasibility of on-chip ac-coupling, and noise performance, we chose an inverting amplifier structure with capacitive feedback. In addition, to provide dc bias path, we used off-state MOSFET switches as pseudo-resistors of very large resistance in the giga-ohm range. The large resistance enables on-chip ac-coupling with sufficient noise performance. A fast start-up is achieved by turning-on the switch for a short period during the preamplifier start-up. The gain of the preamplifier can be programmed from 0 dB to 21 dB with 3 dB steps. A 2-stage pseudo-class-AB amplifier was adopted to reduce power consumption. The proposed preamplifier was implemented using a 28 nm CMOS process and achieves 107 dB dynamic range in a 20 kHz bandwidth under 0 dB gain setting and balanced differential input signal. The preamplifier dissipates a power of 270 μW with a 1.8 V supply.

Sympathetic innervation of the mouse kidney and liver arising from prevertebral ganglia.

The sympathetic nervous system (SNS) plays a crucial role in the regulation of renal and hepatic functions. Although sympathetic nerves to the kidney and liver have been identified in many species, specific details are lacking in the mouse. In the absence of detailed information of sympathetic prevertebral innervation of specific organs, selective manipulation of a specific function will remain challenging. Despite providing major postganglionic inputs to abdominal organs, limited data are available about the mouse celiac-superior mesenteric complex. We used tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DbH) reporter mice to visualize abdominal prevertebral ganglia. We found that both the TH and DbH reporter mice are useful models for identification of ganglia and nerve bundles. We further tested if the celiac-superior mesenteric complex provides differential inputs to the mouse kidney and liver. The retrograde viral tracer, pseudorabies virus (PRV)-152 was injected into the cortex of the left kidney or the main lobe of the liver to identify kidney-projecting and liver-projecting neurons in the celiac-superior mesenteric complex. iDISCO immunostaining and tissue clearing were used to visualize unprecedented anatomical detail of kidney-related and liver-related postganglionic neurons in the celiac-superior mesenteric complex and aorticorenal and suprarenal ganglia compared with TH-positive neurons. Kidney-projecting neurons were restricted to the suprarenal and aorticorenal ganglia, whereas only sparse labeling was observed in the celiac-superior mesenteric complex. In contrast, liver-projecting postganglionic neurons were observed in the celiac-superior mesenteric complex and aorticorenal and suprarenal ganglia, suggesting spatial separation between the sympathetic innervation of the mouse kidney and liver.

Organization of the inputs and outputs of the mouse superior colliculus

The superior colliculus (SC) receives diverse and robust cortical inputs to drive a range of cognitive and sensorimotor behaviors. However, it remains unclear how descending cortical input arising from higher-order associative areas coordinate with SC sensorimotor networks to influence its outputs. Here, we construct a comprehensive map of all cortico-tectal projections and identify four collicular zones with differential cortical inputs: medial (SC.m), centromedial (SC.cm), centrolateral (SC.cl) and lateral (SC.l). Further, we delineate the distinctive brain-wide input/output organization of each collicular zone, assemble multiple parallel cortico-tecto-thalamic subnetworks, and identify the somatotopic map in the SC that displays distinguishable spatial properties from the somatotopic maps in the neocortex and basal ganglia. Finally, we characterize interactions between those cortico-tecto-thalamic and cortico-basal ganglia-thalamic subnetworks. This study provides a structural basis for understanding how SC is involved in integrating different sensory modalities, translating sensory information to motor command, and coordinating different actions in goal-directed behaviors.

Ring-Oscillator with Multiple Transconductors for Linear Analog-to-Digital Conversion

This paper proposes a new circuit-based approach to mitigate nonlinearity in open-loop ring-oscillator-based analog-to-digital converters (ADCs). The approach consists of driving a current-controlled oscillator (CCO) with several transconductors connected in parallel with different bias conditions. The current injected into the oscillator can then be properly sized to linearize the oscillator, performing the inverse current-to-frequency function. To evaluate the approach, a circuit example has been designed in a 65-nm CMOS process, leading to a more than 3-ENOB enhancement in simulation for a high-swing differential input voltage signal of 800-mVpp, with considerable less complex design and lower power and expected area in comparison to state-of-the-art circuit based solutions. The architecture has also been checked against PVT and mismatch variations, proving to be highly robust, requiring only very simple calibration techniques. The solution is especially suitable for high-bandwidth (tens of MHz) medium-resolution applications (10–12 ENOBs), such as 5G or Internet-of-Things (IoT) devices.

Analysis of Limits of CNTFET Devices through the Design of a Differential Amplifier

In this paper, in order to analyze the limits of CNTFET devices, we study the behavior of a differential amplifier based on CNTFET for application between 50 GHz and 500 GHz, determining the highest gain achievable with low noise level. In particular the examined circuit presents a differential input and single ended output, in which each CNTFET is composed by a single CNT, having the same diameter. The analysis is done without considering embedding parasitic effects since our aim is to study the intrinsic limits of CNTFET. We find a solution that is near optimum for gain and noise. In particular we obtain that, using CNTFETs whose channel length is 25 nm, it is possible to reach 27.0 dB gain at 50 GHz and 19.7 dB gain at 500 GHz with a noise spectral power density noise 95 nV/Hz1/2 and 85 nV/Hz1/2 respectively.