Standard Deviation Of Latency Research Articles

Web Application Development Skin Lesion Classification Using Transfer Learning InceptionResNet-v2

The development of machine learning continues from various domains where automation systems are needed. Advanced learning models, such as Convolutional Neural Networks (CNNs) in deep learning, can classify and identify objects even beyond human capabilities. One application is the classification of medical images skin cancer. Automatic diagnosis of skin cancer images is still challenging for CNNs. The use of transfer learning on classification has been leveraged for mobile, accurate, and fast automatic diagnosis. However, such models are imperfect in the categorization of skin lesions. Therefore, this study developed a web application for multiclass classification of 7 classes of disease through Streamlit and HuggingFace, with datasets from HAM10000 using TF Lite-conversion InceptionResNetV2. TF Lite-converted and the model’s classification reports were analyzed. The results on EarlyStopping overall accuracy were 87.56%, top-2 95.05%, and top-3 97.46%. Moreover, latency and classification duration were measured on Streamlit Share and HuggingFace Spaces. The findings are Streamlit has a faster average latency (1.17 ms) than HuggingFace (1.49 ms). The latency standard deviation on HuggingFace less consitent (0.49 ms) than Streamlit (0.10 ms). The HuggingFace classification average duration and standard deviation is 116 ms and 5 ms, while Streamlit is better at 97 ms and 2 ms respectively.

Evaluation of Filtering Techniques applied to simulated Electroencephalogram signals for Visual Evoked Potential Detection

Introduction: In this paper, it is presented an assessment of different windowing techniques and denoising methods applied to detect the Visual Evoked Potential (VEP) contained into the electroencephalographic (EEG) signals. The objective is to analyze advantages and disadvantages of each technique performance to identify correctly the VEP waveform and to quantify the latency which is a parameter commonly used as an indicator of ocular diseases. Method: Assessment of techniques was performed considering rigorous controlled conditions on the signal set, to assure that obtained results were linked just to the technique performances and avoid any undesirable effect due to the natural interference of acquisition of signals. For this reason, a simulated signals set was created based on a typical VEP waveform commonly registered around 100ms after an external stimulus was applied in the routine clinical study. Additionally, two evaluation stages were considered: fixed latency parameters stage and random latency parameters stage.Results: The best results without filter was with rectangular window and the use of elliptic filter can help to extract the VEP with a rectangular window too. For wavelet denoising the best result is Biorthogonal 2.6 wavelet with a Hamming window. Discussion or Conclusion: Five parameters were proposed to assessment the VEP extraction performed: signal noise ratio (SNR) mean square error (MSE), average latency (AL), latency standard deviation (LSD) and latency correlation variance (LCV) as representative factors to be considered on evaluations of VEP extraction methods. SNR and MSE were focused to assess the level of noise that remain in signal after windowing & denoising method was applied. In the other hand AL, LSD and LCV were oriented to evaluate the impact of the method on the VEP latency estimation.

Cognitive Effects of Repeated Acute Exposure to Very High Altitude Among Altitude-Experienced Workers at 5050 m.

Background: We investigated altitude effects on different cognitive domains among perennial shift-workers at the Atacama Large Millimeter/submillimeter Array Observatory (5050 m), Chile. Materials and Methods: Twenty healthy male workers were recruited and assigned to either a moderate-altitude first (MAF group, Test 1: 2900 m and Test 2: 5050 m) or to a high-altitude first (HAF group, Test 1: 5050 m and Test 2: 2900 m). Test 1 was conducted at the beginning and Test 2 at the end of the shift-work week. Processing speed (RTI, reaction time), attention (AST, attention-switching task, and RVP, rapid visual processing), and executive function (OTS, One Touch Stockings of Cambridge) were assessed. Results: Of the three cognitive domains assessed, only processing speed showed altitude-at-test group interaction (RTI median five choice reaction time: F1, 17 = 6.980, [Formula: see text] = 0.291, p = 0.017). With acclimatization, there was a decrease in AST reaction latency mean (t17 = -2.155, dz = 1.086, p = 0.046), an increase in RVP accuracy (t17 = 2.733, dz = 1.398, p = 0.014), and a decrease in OTS mean latency first choice (t17 = -2.375, dz = 1.211, p = 0.03). Decreased variability in cognitive function was observed in AST reaction latency standard deviation (t17 = -2.524, dz = 1.282, p = 0.022) and in RVP response latency standard deviation (t17 = -2.35, dz = 1.177, p = 0.03) with acclimatization. At 5050 m of elevation, SpO2 was positively correlated with executive function in the MAF group (OTS problems solved on first choice: r(5) = 0.839, p = 0.018) and negatively correlated with executive function latency standard deviations in the HAF group (OTS latency to first choice standard deviation: r(10) = -0.618, p = 0.032). Conclusions: Our findings highlight the importance of acclimatization and improvement of blood oxygen level, even among high altitude-experienced workers, to optimize performance of cognitively demanding work and reduce high altitude-associated health risks.

Allopregnanolone Effects on Transmission in the Brain Stem Solitary Tract Nucleus (NTS)

During pregnancy, the progesterone metabolite, allopregnanolone (ALLO), becomes elevated and has been associated with altered levels within the CNS and resulting changes in GABAA receptor function. Pregnant animals poorly compensate reflexes for a decrease in blood pressure during hemorrhage. Previous works suggested that ALLO decreases baroreflex responses by central actions, however, the underlying mechanisms are poorly understood. In this study, we tested ALLO actions on visceral afferent synaptic transmission at second-order neurons within medial portions of the nucleus tractus solitarius (NTS) using hindbrain slices from non-pregnant female rats. Solitary tract (ST) stimulation-evoked excitatory postsynaptic currents (ST-eEPSCs) in NTS neurons directly connected to vagal afferents within the ST. ST-eEPSCs were functionally identified as monosynaptic by the latency characteristics (low jitter = standard deviation of latency, ≤200 μs) to ST stimulation. Such second-order neurons all displayed spontaneous inhibitory postsynaptic currents (sIPSCs), and low micromolar concentrations of ALLO increased frequency and decay time. At submicromolar concentrations, ALLO induced a tonic, GABAergic inhibitory current and suppressed ST-eEPSCs’ amplitude. While GABAA receptor antagonist, bicuculline, blocked all ALLO effects, gabazine only blocked sIPSC actions. In current-clamp mode, ALLO perfusion increased failure of ST stimulation to trigger action potentials in most neurons. Thus, our results indicate that ALLO acts to suppress visceral afferent ST synaptic transmission at first synapses by activating pharmacologically distinct GABAA subtypes at different concentration ranges. This ALLO-mediated attenuated visceral afferent signal integration in NTS may underlie reflex changes in blood pressure during gestation.

ERP variation may be negatively correlated with P300 speller performance

ERP variation may be negatively correlated with P300 speller performance

Analysis of a purely conductance-based stochastic nerve fibre model as applied to compound models of populations of human auditory nerve fibres used in cochlear implant simulations.

The study presents the application of a purely conductance-based stochastic nerve fibre model to human auditory nerve fibres within finite element volume conduction models of a semi-generic head and user-specific cochleae. The stochastic, threshold and temporal characteristics of the human model are compared and successfully validated against physiological feline results with the application of a mono-polar, bi-phasic, cathodic first stimulus. Stochastic characteristics validated include: (i) the log(Relative Spread) versus log(fibre diameter) distribution for the discharge probability versus stimulus intensity plots and (ii) the required exponential membrane noise versus transmembrane voltage distribution. Intra-user, and to a lesser degree inter-user, comparisons are made with respect to threshold and dynamic range at short and long pulse widths for full versus degenerate single fibres as well as for populations of degenerate fibres of a single user having distributed and aligned somas with varying and equal diameters. Temporal characteristics validated through application of different stimulus pulse rates and different stimulus intensities include: (i) discharge rate, latency and latency standard deviation versus stimulus intensity, (ii) period histograms and (iii) interspike interval histograms. Although the stochastic population model does not reduce the modelled single deterministic fibre threshold, the simulated stochastic and temporal characteristics show that it could be used in future studies to model user-specific temporally encoded information, which influences the speech perception of CI users.

Round-trip DRAM Access Fairness in 3D NoC-based Many-core Systems

In 3D NoC-based many-core systems, DRAM accesses behave differently due to their different communication distances and the latency gap of different DRAM accesses becomes bigger as the network size increases, which leads to unfair DRAM access performance among different nodes. This phenomenon may lead to high latencies for some DRAM accesses that become the performance bottleneck of the system. The paper addresses the DRAM access fairness problem in 3D NoC-based many-core systems by narrowing the latency difference of DRAM accesses as well as reducing the maximum latency. Firstly, the latency of a round-trip DRAM access is modeled and the factors causing DRAM access latency difference are discussed in detail. Secondly, the DRAM access fairness is further quantitatively analyzed through experiments. Thirdly, we propose to predict the network latency of round-trip DRAM accesses and use the predicted round-trip DRAM access time as the basis to prioritize the DRAM accesses in DRAM interfaces so that the DRAM accesses with potential high latencies can be transferred as early and fast as possible, thus achieving fair DRAM access. Experiments with synthetic and application workloads validate that our approach can achieve fair DRAM access and outperform the traditional First-Come-First-Serve (FCFS) scheduling policy and the scheduling policies proposed by reference [7] and [24] in terms of maximum latency, Latency Standard Deviation (LSD)1 and speedup. In the experiments, the maximum improvement of the maximum latency, LSD, and speedup are 12.8%, 6.57%, and 8.3% respectively. Besides, our proposal brings very small extra hardware overhead (<0.6%) in comparison to the three counterparts.

Usefulness of the measurement of saccadic refixation in the diagnosis of attention-deficit hyperactivity disorder/hyperkinetic disorder in adults

Abstract Background: The aim of the research is to evaluate the usefulness of the measurement of saccadic refixation in the diagnosis of attention-deficit hyperactivity disorder (ADHD)/hyperkinetic disorder (HKD) in adults. Methods: Seventy-eight individuals were examined: 40 with ADHD/HKD and 38 healthy ones. A noninvasive eye movement examination using the Saccadometer (Advanced Clinical Instrumentation, Cambridge, UK) was applied. Two saccadic tests, prosaccades task (PT) and antisaccades task (AT), were carried out. Results: Based on the results, we can assume that selected parameters, such as latency, standard deviation of latency, promptness, and correctness (directional errors), in individuals with ADHD/HKD differ statistically in the relevant parameters from the healthy ones. The latency and the standard deviation of latency in ADHD/HKD participants are greater when compared to healthy ones. ADHD/HKD participants have a greater number of directional errors in comparison to healthy ones. Conclusions: The standard deviation of latency prosaccades is a good parameter for distinguishing people from both groups. An important and innovative solution in this study in comparison to the studies of other authors, who reached similar results, is the use of an automatically calibrating system (autonomous) adapted for clinical use as well as a quantitative analysis of the saccadic parameters.

One model fits all: Explaining many aspects of number comparison within a single coherent model-A random walk account.

The time required to determine the larger of 2 digits decreases with their numerical distance, and, for a given distance, increases with their magnitude (Moyer & Landauer, 1967). One detailed quantitative framework to account for these effects is provided by random walk models. These chronometric models describe how number-related noisy partial evidence is accumulated over time; they assume that the drift rate of this stochastic process varies lawfully with the numerical magnitude of the digits presented. In a complete paired number comparison design we obtained saccadic choice responses of 43 participants, and analyzed mean saccadic latency, error rate, and the standard deviation of saccadic latency for each of the 72 digit pairs; we also obtained mean error latency for each numerical distance. Using only a small set of meaningfully interpretable parameters, we describe a variant of random walk models that accounts in considerable quantitative detail for many facets of our data, including previously untested aspects of latency standard deviation and error latencies. However, different from standard assumptions often made in random walk models, this account required that the distributions of step sizes of the induced random walks are asymmetric. We discuss how our findings can help in interpreting complex findings (e.g., conflicting speed vs. accuracy trends) in applied studies which use number comparison as a well-established diagnostic tool. Finally, we also describe a novel effect in number comparison, the decrease of saccadic response amplitude with numerical distance, and suggest an interpretation using the conceptual framework of random walk models. (PsycINFO Database Record

Depressed TS-evoked glutamatergic transmission on NTS neurons of rats submitted to intermittent hypoxia is due to reduced number of functional synapses

Chronic intermittent hypoxia (CIH) induces changes in the cardiovascular and respiratory neural control, including reduction in afferent neurotransmission on nucleus tractus solitarii (NTS) neurons. Here we studied the mechanisms involved in this reduction in NTS neurons of CIH rats. Male juvenile rats were exposed to 10days of CIH and after this period, Tractus Solitarii (TS)-evoked glutamatergic post-synaptic currents (eEPSCs) were recorded in horizontal brainstem slices. Neurons were classified according to the standard deviation (SD) of latency for eEPSCs as 2nd-order neurons (latency SD<250μs) and putative higher-order neurons (latency SD>250μs).

Distinct target cell-dependent forms of short-term plasticity of the central visceral afferent synapses of the rat

BackgroundThe visceral afferents from various cervico-abdominal sensory receptors project to the dorsal vagal complex (DVC), which is composed of the nucleus of the solitary tract (NTS), the area postrema and the dorsal motor nucleus of the vagus nerve (DMX), via the vagus and glossopharyngeal nerves and then the solitary tract (TS) in the brainstem. While the excitatory transmission at the TS-NTS synapses shows strong frequency-dependent suppression in response to repeated stimulation of the afferents, the frequency dependence and short-term plasticity at the TS-DMX synapses, which also transmit monosynaptic information from the visceral afferents to the DVC neurons, remain largely unknown.ResultsRecording of the EPSCs activated by paired or repeated TS stimulation in the brainstem slices of rats revealed that, unlike NTS neurons whose paired-pulse ratio (PPR) is consistently below 0.6, the distribution of the PPR of DMX neurons shows bimodal peaks that are composed of type I (PPR, 0.6-1.5; 53% of 120 neurons recorded) and type II (PPR, < 0.6; 47%) neurons. Some of the type I DMX neurons showed paired-pulse potentiation. The distinction of these two types depended on the presynaptic release probability and the projection target of the postsynaptic cells; the distinction was not dependent on the location or soma size of the cell, intensity or site of the stimulation, the latency, standard deviation of latency or the quantal size. Repeated stimulation at 20 Hz resulted in gradual and potent decreases in EPSC amplitude in the NTS and type II DMX neurons, whereas type I DMX neurons displayed only slight decreases, which indicates that the DMX neurons of this type could be continuously activated by repeated firing of primary afferent fibers at a high (~10 Hz) frequency.ConclusionsThese two general types of short-term plasticity might contribute to the differential activation of distinct vago-vagal reflex circuits, depending on the firing frequency and type of visceral afferents.

Every microsecond counts

Many network applications have stringent end-to-end latency requirements, including VoIP and interactive video conferencing, automated trading, and high-performance computing---where even microsecond variations may be intolerable. The resulting fine-grain measurement demands cannot be met effectively by existing technologies, such as SNMP, NetFlow, or active probing. We propose instrumenting routers with a hash-based primitive that we call a Lossy Difference Aggregator (LDA) to measure latencies down to tens of microseconds and losses as infrequent as one in a million. Such measurement can be viewed abstractly as what we refer to as a coordinated streaming problem, which is fundamentally harder than standard streaming problems due to the need to coordinate values between nodes. We describe a compact data structure that efficiently computes the average and standard deviation of latency and loss rate in a coordinated streaming environment. Our theoretical results translate to an efficient hardware implementation at 40 Gbps using less than 1% of a typical 65-nm 400-MHz networking ASIC. When compared to Poisson-spaced active probing with similar overheads, our LDA mechanism delivers orders of magnitude smaller relative error; active probing requires 50--60 times as much bandwidth to deliver similar levels of accuracy.

Cortical excitability and response variability of transcranial magnetic stimulation.

The magnetic evoked potential (MEP) following transcranial magnetic stimulation is subject to several sources of variability. In this study, relationships between stimulus intensity and MEP latency, amplitude, duration, and area of the hypothenar muscles were assessed in 12 right- and 14 left-handed subjects. Effects of handedness, coil orientation, intensity of stimulation, and intersubject variability on these relationships were analyzed. The intraindividual variability was analyzed as the standard deviation (SD) and the coefficient of variation (CV) of four trials. The mean response threshold was significantly lower (p < 0.0001) for preferential stimulation (32%) than for nonpreferential stimulation (45%). With increasing stimulus intensities, MEP amplitudes still increased at 100% intensity in some subjects while in others the stimulus response-relations saturated. MEP amplitudes at an intensity of 20% above threshold ranged between 6 and 100% of MEP amplitude at maximum intensity. Differences between dominant and non-dominant hands were not seen, regardless of handedness. The SD of latency, amplitude, duration, or area depended on stimulus intensity. The CV however, was influenced by the intensity of stimulation: The CV for amplitude decreased from 46% at threshold to 10% at higher intensities. The variability of the MEP amplitude is only related to stimulus intensity when it is expressed in relation to it but not when it is expressed in absolute terms. The stimulus-response relation offers a more extensive measure of cortical excitability than the use of thresholds alone for the measurement of cortical excitability. The question can be raised whether high intensities should be used for clinical testing rather than threshold-related intensities.

The predictability of saccadic latency in a novel voluntary oculomotor task

When a subject makes a voluntary saccade to a goal, which is opposite and equal to the stimulus step (“anti” task), the mean and standard deviation of latency are predictable from the latencies of the conventional “normal” task. There is no significant improvement with practice. In each of 8 subjects normal task latency is the sum of a relatively fixed delay of apparent value 144 msec (true value probably less), plus a very variable idiosyncratic delay. A simple model is applied to the “anti” task, the Wheeless 2-step task and forewarning. While the saccadic system shows great flexibility in its choice of goal, it is rather stereotyped in timing.

Intersubject variability of the auditory-evoked brain stem potentials.

The potential usefulness of the auditory-evoked brain stem potentials in audiological assessment has been the subject of increased clinical enquiry. Several requirements need to be met by any response parameter if it is to be clinically useful: parameters should show a clear, and ideally simple, relationship with stimulus intensity; they should be stable within any subject under fixed stimulation conditions and intersubject variability within any clinical group should be small. Response latency has been shown to satisfy the first two of these conditions. However, intersubject variability has been less clearly defined. In a sample of normal controls we have found that the standard deviation of latency at any specific intensity was substantial, exceeding the difference found between mean responses at neighbouring intensities of auditory stimulation. In an investigation of the origins of this variability we have found a clear gender difference, maximal for later components in which the male responses were significantly later than the female responses. The clinical significance of this finding can be seen in the latency intensity input/output function. By treating each gender group separately, intersubject variance values were reduced by approximately 40% compared with the total group variance, so enhancing the usefulness of latency as a parameter in the objective assessment of auditory function.

The theoretical channel capacity of a single neuron as determined by various coding systems

The information channel capacity of a model neuron with a fixed refractory period δ has been calculated for optimum continuous time interval coding. Two types of noise perturbations have been considered, a Gaussian probability distribution and a rectangular distribution of the time of occurrence of the response to a stimulus. Laboratory measurements indicate a Gaussian distribution with a standard deviation of latency σ, of about 5 μsec gives the best fit to an actual nerve fiber. This results in a maximum information transmission of slightly over 4000 bits per second. The results are compared with the discrete theory of MacKay and McCulloch.