Significant Stimuli Research Articles

Decoding dynamic faces and scenes without awareness under dis-continuous flash suppression

In the perceptual sciences, there is an ongoing debate about the depth of unconscious processing. Here, we address this issue by implementing three improvements with regards to paradigm, stimuli and analyses to explore the neural correlates of unconscious face processing. Our results demonstrated that conscious faces elicited broader univariate activations than conscious scenes. Such results were absent when faces/scenes were suppressed and invisible (n = 43). However, further whole-brain multivariate classification revealed that both static and dynamic invisible faces could be distinguished from scenes in the occipital-temporal region. ROI analysis showed that bilateral FFA and OFA could differentiate dynamic invisible faces from dynamic invisible scenes. These findings suggest that interocularly suppressed faces are still processed in-depth in the ventral visual stream. Therefore, our study highlights the importance of optimizing stimulus signal, experimental paradigm, and analysis to extract unconscious signals in the brain.

An electronic tongue system with automatic sample mixing function for long-term in-situ monitoring of chemical reactions

As technology advanced, the demand for automation and in-situ monitoring of chemical reactions soared. This article introduced a novel in-situ monitoring device that utilized an electronic tongue system. Comprising a centrifuge, experimental unit, microfluidic chip, and electronic tongue plug (or stopper), the device facilitated simultaneous sample mixing, stimulus signaling, and response signal collection. The chip, serving as the carrier for the samples, provided a stable and sealed environment, which was crucial for electronic tongue monitoring. Acting as the plug for the chip, the electronic tongue enabled in-situ monitoring of liquids. Proven effective in studying nucleotide selection and amino acid regulation during peptide formation, this device broadened the possibilities of automated monitoring designs and was deployed in the Wentian module of Tiangong space station, advancing the application prospects of the electronic tongue system in space chemistry.

Male rats choose higher doses of nicotine in anticipation of a future non-drug period.

Humans and animals use information about future access to rewards to influence their behaviour in the present, however the evidence for this is largely anecdotal. Here we use the nicotine intravenous self-administration paradigm to ask whether rats can use an auditory stimulus signalling a long (450s) signalled time-out on the next trial to influence their nicotine intake in the present. Rats were trained to choose between low (15µg/kg/infusion), medium (30µg/kg/infusion) or high (60µg/kg/infusion) doses of nicotine on any given trial. Trials either had a 'light' trial with no tone and a standard 20s post-infusion time-out, a 'short-tone' trial where a tone was presented but the time-out remained at 20s, or a 'long-tone' trial where a second tone played and was accompanied by a long 450s time-out period. During training rats clearly showed that dose selection was based on both the dose on the previous trial and the latency between infusions. When tones were presented, rats shifted their preference from the low dose to the high dose when the long-delay tone was presented, and this choice was particularly pronounced when the rat had previously selected a low dose. Together these findings are the first evidence that rats can regulate their nicotine intake in the present in anticipation of a future non-drug period. This result is discussed with respect to theories of negative reinforcement.

Sucrose synthase gene family in common bean during pod filling subjected to moisture restriction.

In common bean (Phaseolus vulgaris L.), leaf photosynthesis is significantly reduced under drought conditions. Previous studies have shown that some drought-tolerant cultivars use the pod walls to compensate the decreased photosynthesis rate in leaves by acting as temporary reservoirs of carbohydrates to support seed filling. Here, we describe a comprehensive molecular characterization of sucrose synthase (SUS, EC 2.4.1.13) gene family through a genome-wide analysis and evaluated the effects of terminal drought on reproductive structures, specifically the pod walls. Seven PvSUS genes were located on six different chromosomes and had 8-16 intron-exon structures (8-16 exons). The PvSUS protein sequences revealed conserved catalytic domains, with molecular weights ranging from 90.5 kDa to 105.1 kDa and lengths from 799 to 929 amino acids. Phylogenetic analysis grouped these sequences into three main clusters with seven subgroups, indicating divergence from SUS sequences in other plant species. Using a docking sequence, we predicted three-dimensional (3-D) structures and evaluated the active sites. Bioinformatics analysis of promoter regions suggested that PvSUS genes may respond to light, hormone signaling, and stress stimuli. Greenhouse experiments were conducted using the cv. OTI, identified as having intermediate drought tolerance. Plants at the R8 growth stage were maintained with regular irrigation at 100% field capacity (FC) or with water restriction to maintain 50% of field capacity. Pods were harvested 5 days, 10 days, 15 days, and 20 days after anthesis. An increase in PvSUS activity under water restriction was associated with higher levels of fructose, while sucrose concentration also increased. qRT-PCR analysis revealed that PvSUS1, PvSUS3, and PvSUS4 were strongly expressed during seed development under water restriction. The fluorescent sucrose analog esculin indicated that transport across the plasma membrane might contribute to the increase in the pith cell diameter of pedicels. The results provide a systematic overview of the PvSUS gene family in P. vulgaris, offering a framework for further research and the potential functional application of PvSUS genes.

Gun Position Servo System Auto Tuning Control Based on Correlation Identification Method

Abstract Position servo systems are used in kinds of gun weapons widely. It plays an important role for aiming to ground target or tracking to moving target. In this paper, a gun position servo system auto tuning control based on correlation identification method is presented. The M-sequence generator is constructed which is as a stimulus signal of the plant. Through signals acquisition of input and output of the plant speed loop, the cross-correlation function of the speed loop input and output can be calculated. Then the impulse response function of the position servo system plant speed loop can be identified. According to the identification results, position controller parameters are tuned based on the given width mid-frequency interval of the open loop position servo system. Last, simulations are carried out to a gun position servo system. The simulation results show that the identified impulse response function has high accuracy. Through the parameters tuning, the stable margin can be maintained which is determined by the width of mid-frequency interval for different speed loop time constant.

Multiscale interstitial fluid computation modeling of cortical bone to characterize the hydromechanical stimulation of lacunar-canalicular network.

Bone tissue is a biological composite material with a complex hierarchical structure that could continuously adjust its internal structure to adapt to the alterations in the external load environment. The fluid flow within bone is the main route of osteocyte metabolism, and the pore pressure as well as the fluid shear stress generated by it are important mechanical stimuli perceived by osteocytes. Owing to the irregular multiscale structure of bone tissue, the fluid stimulation that lacunar-canalicular network (LCN) in different regions of the tissue underwent remained unclear. In this study, we constructed a multiscale conduction model of fluid flow stimulus signals in bone tissue based on the poroelasticity theory. We analyzed the fluid flow behaviors at the macro-scale (whole bone tissue), macro-meso scale (periosteum, interstitial bone, osteon and endosteum), and micro-scale (lacunar-osteocyte-canalicular) levels. We explored how fluid stimulation at the tissue level correlated with that at the cellular level in cortical bone and characterized the distributions of the pore pressure, fluid velocity and fluid shear stress that the osteocytes experienced across the entire tissue structure. The results showed that the initial conditions of intramedullary pressure had a significant impact on the pore pressure of Haversian systems, but had a relatively small influence on the fluid velocity. The osteocyte which were located at different positions in the bone tissue received very distinct fluid stimuli. Osteocytes in the vicinity of the Haversian Canals experienced higher fluid shear stress stimulation. When the permeability of the LCN was within the range from 10-21m2 to 10-18m2, the distribution of pressure, fluid velocity and fluid shear stress within the osteon near the periosteum and endosteum was significantly different from that in other parts of the bone. However, when the permeability was less than 10-22m2, such a difference did not exist. Particularly, the flow velocity at the lacunae was markedly higher than that in the canaliculi. Meanwhile, the pore pressure and fluid shear stress were conspicuously lower than those in the canaliculi. In this study, we considered the interconnections of different biofunctional units at different scales of bone tissue, construct a more complete multiscale model of bone tissue, and propose that osteocytes at different locations receive different fluid stimuli, which provides a reference for a deeper understanding of bone mechanotransduction.

The structural logic of dynamic signaling in the Escherichia coli serine chemoreceptor.

The experimental challenges posed by integral membrane proteins hinder molecular understanding of transmembrane signaling mechanisms. Here, we exploited protein crosslinking assays in living cells to follow conformational and dynamic stimulus signals in Tsr, the Escherichia coli serine chemoreceptor. Tsr mediates serine chemotaxis by integrating transmembrane serine-binding inputs with adaptational modifications of a methylation helix bundle to regulate a signaling kinase at the cytoplasmic tip of the receptor molecule. We created cysteine replacements at Tsr residues adjacent to hydrophobic packing faces of the bundle helices and crosslinked them with a cell-permeable, bifunctional thiol-reagent. We identified an extensively crosslinked dynamic junction midway through the methylation helix bundle that seemed uniquely poised to respond to serine signals. We explored its role in mediating signaling shifts between different packing arrangements of the bundle helices by measuring crosslinking in receptor molecules with apposed pairs of cysteine reporters in each subunit and assessing their signaling behaviors with an in vivo kinase assay. In the absence of serine, the bundle helices evinced compact kinase-ON packing arrangements; in the presence of serine, the dynamic junction destabilized adjacent bundle segments and shifted the bundle to an expanded, less stable kinase-OFF helix-packing arrangement. AlphaFold models of kinase-active Tsr showed a prominent bulge and kink at the dynamic junction that might antagonize stable structure at the receptor tip. Serine stimuli might inhibit kinase activity by shifting the bundle to a less stably-packed conformation that relaxes structural strain at the receptor tip, thereby allowing it to stabilize and freeze kinase activity.

Measuring Microplastic Concentrations in Water by Electrical Impedance Spectroscopy

Plastics are vital for society, but their usage has grown exponentially and contributes to the growth of pollution worldwide. The World Health Organization, WHO, already reported that microplastics (MPs) are found everywhere, in waste and fresh water, and in the air and soil. Regarding water effluents, waste-water treatment plants only minimize the problem, trapping only larger size particles. In contrast, smaller ones remain in oxidation ponds or sewage sludges, or are even released to aquifers environment. Classic procedures for MPs detection are still quite laborious, and are usually conducted off-line, involving several steps and expensive equipment. Electrical Impedance Spectroscopy, EIS, is a technique that allows the analysis of a system’s electrical response, yielding helpful information about its domain-dependent on physical-chemical properties. Due to the superficial electronegativity of MPs’ particles, EIS may allow to attain the purpose of the present work: to provide a fast and reliable method to detect/estimate MPs’ concentration in water effluents. Among the most common microplastics are Polyethylene, PE, and Polyvinyl Chloride, PVC. Using the developed setup and experimental data collection methodology, the authors could differentiate between MPs’ suspensions containing the same concentration of the different evaluated MPs, PVC and PE, and assess PVC concentration variation, in the interval between 0.03 to 0.5 g (w/w), with an error, estimated based on the obtained impedance modulus, around or below 3% for the entire stimulus signal frequency range (from 100 Hz to 40 MHz) for the PVC particles.

Mechanisms and treatment of atherosclerosis: focus on macrophages.

Macrophages are the basic mediators and coordinators of various types of chronic inflammation and play a crucial role in the formation and development of atherosclerosis (AS). In the complex microenvironment of atherosclerotic plaques, macrophages of different sources are exposed to different signal stimuli and thus polarized into various subpopulations. Various types of macrophages with predominantly M1 and M2 phenotypes also play different regulatory roles in the initiation and progression of AS. Lipid-lowering drugs, mainly statins, are widely used in clinical practice, but the adverse reactions are obvious and there is a lack of personalized treatment. Emerging targeted macrophage and Traditional Chinese medicine (TCM)-related therapies can regulate the cellular microenvironment, inhibit the polarization of M1 macrophages, and promote the activation of M2 macrophages, providing new ideas for the prevention and treatment of AS.

Gelatin-Modified Bioactive Glass for Treatment of Dentin Hypersensitivity.

When dentin is directly exposed to the oral cavity for various reasons, such as a lack of enamel on the tooth surface, external stimuli to the dentin often cause transient discomfort known as dentin hypersensitivity. In order to block the incoming stimulus signal, an ideal treatment is to induce the production of minerals to block the dentinal tubules. In this work, a dentin-desensitizing plugging material was prepared by modifying mesoporous bioactive glass with gelatin, the mineralization and desensitization effects of which were compared with Gluma in in vitro experiments. These experiments confirmed that gelatin-modified bioactive glass (MBG@PDA@Gel) is more effective than traditional desensitizing agents at blocking dentin tubules. Following the successful synthesis of MBG@PDA@Gel, as confirmed by scanning electron microscopy, transmission electron microscopy, and other tests, the treatment of demineralized dentin with MBG@PDA@Gel demonstrated that the dentinal tubules were tightly blocked under scanning electron microscopy. MBG@PDA@Gel induces minerals in deeper layers of dentinal tubules, promoting remineralization and forming a unified structure with the tubule blockage. Animal studies showed that MBG@PDA@Gel can remineralize demineralized dentin, and it is stable in the oral cavity and does not fall out. MBG@PDA@Gel not only enhances the biocompatibility of the nanoparticle but also results in an overall uniform and rapid remineralization of the demineralized dentin.

Design of Optogenetic Microimplants for the Treatment of Neurodegenerative Disease

In the context of global aging, neurodegenerative diseases such as Alzheimer’s disease have become important issues in global public health and scientific research. This is due to their soaring incidence, serious impact on patients’ quality of life, and the huge burden they place on families and social economies. However, current treatments, such as drug therapy and deep brain stimulation, have obvious shortcomings. Moreover, there is a lack of precise neuromodulation tools to study the pathogenesis of these diseases In order to solve these problems, optogenetics has attracted attention in recent years, which uses light as a stimulus signal carrier and can realize the detection and control of neurodegenerative diseases at the level of neurons and neural circuits by implanting micro-implants such as μ leds. This review summarize the recent advances in microimplant technology in the fields of optogenetics and neuroscience, and summarize the development and application of optogenetic microimplants for the treatment of neurodegenerative diseases in detail.

How the Structure of Signaling Regulation Evolves: Insights from an Evolutionary Model.

To remain responsive to environmental changes, signaling pathways attenuate their activity with negative feedback loops (NFLs), where proteins produced upon stimulation downregulate the response. NFLs function both upstream of signaling to reduce input and downstream to reduce output. Unlike upstream NFLs, downstream NFLs directly regulate gene expression without the involvement of intermediate proteins. Thus, we hypothesized that downstream NFLs evolve under more stringent selection than upstream NFLs. Indeed, genes encoding downstream NFLs exhibit a slower evolutionary rate than upstream genes. Such differences in selective pressures could result in the robust evolution of downstream NFLs while making the evolution of upstream NFLs more sensitive to changes in signaling proteins and stimuli. Here, we test these assumptions within the context of immune signaling. Our minimal model of immune signaling predicts robust evolution of downstream NFLs to changes in model parameters. This is consistent with their critical role in regulating signaling and the conservative rate of evolution. Furthermore, we show that the number of signaling steps needed to activate a downstream NFL is influenced by the cost of signaling. Our model predicts that upstream NFLs are more likely to evolve under a shorter half-life of signaling proteins, absence of host-pathogen co-evolution, and a high infection rate. Although it has been proposed that NFLs evolve to reduce the cost of signaling, we show that a high cost does not necessarily predict the evolution of upstream NFLs. The insights from our model have broad implications for understanding the evolution of regulatory mechanisms across signaling pathways.

Suppression of Visceral Nociception by Selective C-Fiber Transmission Block Using Temporal Interference Sinusoidal Stimulation.

Chronic visceral pain management remains challenging due to limitations in selective targeting of C-fiber nociceptors. This study investigates temporal interference stimulation (TIS) on dorsal root ganglia (DRG) as a novel approach for selective C-fiber transmission block. We employed (1) GCaMP6 recordings in mouse whole DRG using a flexible, transparent microelectrode array for visualizing L6 DRG neuron activation, (2) ex vivo single-fiber recordings to assess sinusoidal stimulation effects on peripheral nerve axons, (3) in vivo behavioral assessment measuring visceromotor responses (VMR) to colorectal distension in mice, including a TNBS-induced visceral hypersensitivity model, and (4) immunohistological analysis to evaluate immediate immune responses in DRG following TIS. We demonstrated that TIS (2000 Hz and 2020 Hz carrier frequencies) enabled tunable activation of L6 DRG neurons, with the focal region adjustable by altering stimulation amplitude ratios. Low-frequency (20-50 Hz) sinusoidal stimulation effectively blocked C-fiber and Aδ-fiber transmission while sparing fast-conducting A-fibers, with 20 Hz showing highest efficacy. TIS of L6 DRG reversibly suppressed VMR to colorectal distension in both control and TNBS-induced visceral hypersensitive mice. The blocking effect was fine-tunable by adjusting interfering stimulus signal amplitude ratios. No apparent immediate immune responses were observed in DRG following hours-long TIS. In conclusion, TIS on lumbosacral DRG demonstrates promise as a selective, tunable approach for managing chronic visceral pain by effectively blocking C-fiber transmission. This technique addresses limitations of current neuromodulation methods and offers potential for more targeted relief in chronic visceral pain conditions.

Evoked Component Analysis (ECA): Decomposing the Functional Ultrasound Signal With GLM-Regularization.

Analysis of functional neuroimaging data aims to unveil spatial and temporal patterns of interest. Existing analysis methods fall into two categories: fully data-driven approaches and those reliant on prior information, e.g. the stimulus time course. While using the stimulus signal directly can help identify the activated brain areas, it is known that the relationship between stimuli and the brain's response exhibits nonlinear and time-varying characteristics. As such, relying completely on the stimulus signal to describe the brain's temporal response leads to a restricted interpretation of the brain function. In this paper, we present a new technique called Evoked Component Analysis (ECA), which leverages prior information up to a defined extent. This is achieved by including the general linear model (GLM) design matrix as a regulatory term and estimating the factor matrices in both space and time through an alternating minimization approach. We apply ECA to 2D and swept-3D functional ultrasound (fUS) experiments conducted with mice. When decomposing 2D fUS data, we employ GLM regularization at various intensities to emphasize the role of prior information. Furthermore, we show that incorporating multiple hemodynamic response functions within the design matrix can provide valuable insights into region-specific characteristics of evoked activity. Finally, we use ECA to analyze swept-3D fUS data recorded from five mice engaged in two distinct visual tasks. Swept-3D fUS images the 3D brain sequentially using a moving probe, resulting in different slice acquisition time instants. We show that ECA can estimate factor matrices with a fine resolution at each slice acquisition time instant and yield higher t-statistics compared to GLM and correlation analysis for all subjects.

Neuromodulation effect of temporal interference stimulation based on network computational model.

Deep brain stimulation (DBS) has long been the conventional method for targeting deep brain structures, but noninvasive alternatives like transcranial Temporal Interference Stimulation (tTIS) are gaining traction. Research has shown that alternating current influences brain oscillations through neural modulation. Understanding how neurons respond to the stimulus envelope, particularly considering tTIS's high-frequency carrier, is vital for elucidating its mechanism of neuronal engagement. This study aims to explore the focal effects of tTIS across varying amplitudes and modulation depths in different brain regions. An excitatory-inhibitory network using the Izhikevich neuron model was employed to investigate responses to tTIS and compare them with transcranial Alternating Current Stimulation (tACS). We utilized a multi-scale model that integrates brain tissue modeling and network computational modeling to gain insights into the neuromodulatory effects of tTIS on the human brain. By analyzing the parametric space, we delved into phase, amplitude, and frequency entrainment to elucidate how tTIS modulates endogenous alpha oscillations. Our findings highlight a significant difference in current intensity requirements between tTIS and tACS, with tTIS requiring notably higher intensity. We observed distinct network entrainment patterns, primarily due to tTIS's high-frequency component, whereas tACS exhibited harmonic entrainment that tTIS lacked. Spatial resolution analysis of tTIS, conducted via computational modeling and brain field distribution at a 13 Hz stimulation frequency, revealed modulation in deep brain areas, with minimal effects on the surface. Notably, we observed increased power within intrinsic and stimulation bands beneath the electrodes, attributed to the high stimulus signal amplitude. Additionally, Phase Locking Value (PLV) showed slight increments in non-deep areas. Our analysis indicates focal stimulation using tTIS, prompting further investigation into the necessity of high amplitudes to significantly affect deep brain regions, which warrants validation through clinical experiments.

High Stability Hydrogel Magnetic Relaxation Switch Sensor Driven by pH for the Sensitive Detection of Cd2.

The traditional magnetic relaxation switching (MRS) sensors have excellent sensitivity, but their stability is poor because the magnetic relaxation signal is easily affected by the external magnetic field or environmental oxidation. In this study, a highly stable hydrogel bead-based MRS (Gel-MRS) sensor was established for the accurate and sensitive detection of Cd2+ in rice. A pH-responsive hydrogel bead was applied as a core element for the target stimulus and transverse relaxation signal transduction. The stability experiments showed that the transverse relaxation time (T2) change of the Gel-MRS sensor was one-seventh that of traditional magnetic nanoparticles under an external magnetic field and less than a fifth that of Fe2+/Fe3+ conversion in air. The excellent stability was due to the fact that T2 of the Gel-MRS sensor came from the swelling system mediated by pH rather than the traditional aggregation/dispersion or Fe2+/Fe3+ conversion of magnetic nanoparticles. In addition, the target Cd2+ could exclusively trigger a pH response of the hydrogel beads, altering the T2, thus resulting in excellent relaxation properties (R2 = 56.89) and pH responsiveness of the Gel-MRS sensor. The swelling process of the hydrogel beads followed quasi-second-order dynamics. The Gel-MRS sensor demonstrated a remarkable limit of detection as low as 0.009 ng/mL for Cd2+, with a linear range of 0.01-5 ng/mL. The excellent stability and sensitivity made the Gel-MRS sensor have great application potential in food and environmental detection.

Characterizing third-order intermodulation distortion of photodetectors based on de-coupling and de-embedding modulation distortion of modulators

A novel, to the best of our knowledge, electro-optical modulation method is proposed for measuring third-order intermodulation distortion of photodetectors (PDs) based on de-coupling and de-embedding modulation distortion of modulators. The method utilizes dual parallel intensity modulation to generate electro-optical stimulus signals with fast and fine sweeping capability, and it eliminates the nonlinear impact of modulators by using low-frequency bias swing, allowing a direct extraction of the third-order output intercept point (OIP3) of PD from the combined nonlinear response contributed by both the modulators and the PD. The OIP3 of PD is frequency-swept measured with our method and compared to those with the conventional method to check for consistency. The proposed method enables a modulator-distortion-free, fast, and fine sweeping measurement of PDs using a simple system.

Pigeons' (Columba livia) intertemporal choice in binary-choice and patch-leaving contexts.

Typical approaches to study self-control present subjects with a simultaneous choice between a larger-later (LL) reinforcer and a smaller-sooner (SS) reinforcer. In contrast, in patch-leaving tasks, subjects choose between staying at a patch for an SS (or LL) reinforcer and leaving for an LL (or SS) reinforcer. Previous studies show that blue jays, monkeys, humans, and rats prefer the SS reinforcer in binary-choice tasks, whereas the same subjects prefer the LL reinforcer in equivalent patch-leaving tasks. The current study systematically replicated this research using pigeons. Six pigeons responded in a binary-choice task and in two patch-leaving tasks in which staying led to an LL (Patch-L) or SS (Patch-S) reinforcer. Across conditions, the SS reinforcer delay varied from 5 to 55 s; the LL reinforcer delay was always 60 s. In binary-choice conditions, subjects preferred the SS reinforcer. In Patch-L and Patch-S conditions, subjects preferred the LL and SS reinforcer, respectively, reflecting a bias to stay at the patch. This bias persisted when the stay response was more effortful and when the delays to both reinforcers were equal. This may reflect a species-specific win-stay bias and the differential consequences of staying (which led to a stimulus signaling food) versus leaving (which led to a stimulus never associated with food). Thus, we propose a conditioned-reinforcement account of intertemporal choice in patch-leaving contexts. We suggest several avenues for further investigations of the mechanisms underlying intertemporal choice in different contexts and question the economic equivalence of the operant and patch-leaving procedures. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Performance During a Task That Simulates Passive Sonar Operator Duties Under Conditions of Varying Workloads.

It is critical to develop and implement lab-based computer experiments that simulate real-world tasks in order to characterize operational requirements and challenges or identify potential solutions. Achieving a high degree of laboratory control, operational generalizability, and ease-of-use for a task is challenging, often leading to the development of tasks that can satisfy some facets but not all. This can result in insufficient solutions that leave real-world stakeholders with unsolved problems. This issue is addressed using a customized passive sonar simulator application that provides extensive researcher control over the design and manipulation of a sonar task; a visual appearance and cognitive demand similar to a true submarine-based sonar task; and a convenient and short training routine for sonar novices. The task requires participants to watch for multiple signal sources of varying appearance and salience and subsequently classify these signals into their respective categories. The current study investigated the effects of stimulus signal strength and signal density on sonar task performance-including metrics of classification accuracy, classification confidence, and response times-finding an interaction between signal density and signal strength that resulted in greater performance errors with high signal density at the weakest signal strength. The lab-based sonar application provides new possibilities for research, not limited to signal intensity and signal density but also through the manipulation of parameters such as the number of unique targets, target appearance, and task duration. This application may illuminate the operational demands that each of these factors may have on operator behavior within the dynamic tasks.

Feasibility exploration of cortical auditory evoked potentials evoked by spectro-temporal modulation signals

Background An objective measurement of speech perception would be valuable in hearing-impaired patients who are unable to perform auditory tasks reliably. Objectives To investigate the feasibility of cortical auditory evoked potentials (CAEPs) evoked by different spectro-temporal modulation (STM) signals and provide reference for the further exploration of acoustic change complex (ACC) in hearing-impaired patients. Method 29 normal hearing (NH) adults were recruited and stimulated randomly by STM signals at 6 spectral modulation rates: 0, 1, 2, 4, 8, 16 cycles/octave, at each of 4 temporal modulation rates: 0, 2, 4, 8 Hz, to elicit ACC response. Results The change of spectral modulation rates ≤ 16 cycles/octave at 0 Hz temporal modulation rate had different impacts on latency. 0, 1 cycles/octave, and 4, 8 Hz made a difference to the P2-N1 amplitude easily. 8, 16 cycles/octave were more unstable in rejection rate. No significant difference existed in waveform repetition rate among different STM rates. No significant interaction effect existed in spectral and temporal modulation. Conclusions STM as a stimulus signal to induce ACC response had its feasibility. 2 cycles/octave at spectral modulation rate and 2 Hz at temporal modulation rate had better stability and waveform repeatability in NH adults.