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Background: Transcranial direct current stimulation (tDCS) has been shown to perturb both cortical neural activity and hemodynamics during (online) and after the stimulation, however mechanisms of these tDCS-induced online and after-effects are not known. Here, online resting-state spontaneous brain activation may be relevant to monitor tDCS neuromodulatory effects that can be measured using electroencephalography (EEG) in conjunction with near-infrared spectroscopy (NIRS).
Method: We present a Kalman Filter based online parameter estimation of an autoregressive (ARX) model to track the transient coupling relation between the changes in EEG power spectrum and NIRS signals during anodal tDCS (2mA, 10min) using a 4×1 ring high-definition montage.
Results: Our online ARX parameter estimation technique using the cross-correlation between log (base-10) transformed EEG band-power (0.5-11.25Hz) and NIRS oxy-hemoglobin signal in the low frequency (≤0.1Hz) range was shown in 5 healthy subjects to be sensitive to detect transient EEG-NIRS coupling changes in resting-state spontaneous brain activation during anodal tDCS. Conventional sliding window cross-correlation calculations suffer a fundamental problem in computing the phase relationship as the signal in the window is considered time-invariant and the choice of the window length and step size are subjective. Here, Kalman Filter based method allowed online ARX parameter estimation using time-varying signals that could capture transients in the coupling relationship between EEG and NIRS signals.
Conclusion: Our new online ARX model based tracking method allows continuous assessment of the transient coupling between the electrophysiological (EEG) and the hemodynamic (NIRS) signals representing resting-state spontaneous brain activation during anodal tDCS.
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http://dx.doi.org/10.1016/j.jneumeth.2016.09.008 | DOI Listing |
Traffic Inj Prev
September 2025
Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin.
Objective: Assessment of submarining occurrence in PMHS (Post-Mortem Human Subject) testing can be challenging, particularly for obese PMHS. This study investigates varied kinetic and kinematic response parameters as potential indicators of submarining. Data from 36 whole-body PMHS frontal sled tests conducted under varying boundary conditions were analyzed, incorporating three spring-controlled seat configurations, two extreme anthropometric profiles, two crash pulses, and two seatback angles.
View Article and Find Full Text PDFPLoS One
September 2025
Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia, Egypt.
Polar protic and aprotic solvents can effectively simulate the maturation of breast carcinoma cells. Herein, the influence of polar protic solvents (water and ethanol) and aprotic solvents (acetone and DMSO) on the properties of 3-(dimethylaminomethyl)-5-nitroindole (DAMNI) was investigated using density functional theory (DFT) computations. Thermodynamic parameters retrieved from the vibrational analysis indicated that the DAMNI's entropy, heat capacity, and enthalpy increased with rising temperature.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
California Institute of Technology, TAPIR, Division of Physics, Mathematics, and Astronomy, Pasadena, California 91125, USA.
In the gravitational-wave analysis of pulsar-timing-array datasets, parameter estimation is usually performed using Markov chain Monte Carlo methods to explore posterior probability densities. We introduce an alternative procedure that instead relies on stochastic gradient-descent Bayesian variational inference, whereby we obtain the weights of a neural-network-based approximation of the posterior by minimizing the Kullback-Leibler divergence of the approximation from the exact posterior. This technique is distinct from simulation-based inference with normalizing flows since we train the network for a single dataset, rather than the population of all possible datasets, and we require the computation of the data likelihood and its gradient.
View Article and Find Full Text PDFJ Appl Lab Med
September 2025
Department of Pathology, Moffitt Cancer Center, Tampa, FL, United States.
Background: Clonal plasma cell disorders, such as multiple myeloma (MM), often cause excretion of monoclonal free light chains (MFLC) into urine that serve as diagnostic markers and can cause renal injury.
Content: Measures of urinary protein excretion (PEx) and MFLC excretion are parameters for diagnosing and managing plasma cell disorders, although the roles are evolving as new diagnostic tools are applied. Current guidelines dictate measuring PEx and MFLC excretion using 24-hour urine specimens, which have multiple shortcomings that compromise the quality of testing, delay results, and are burdensome for patients.
Cereb Cortex
August 2025
Aix-Marseille Université, Institut National de la Santé et de la Recherche Médicale, Institut de Neurosciences des Systèmes (INS) UMR1106, Marseille 13005, France.
Over three decades, statistical parametric mapping has transformed neuroimaging from descriptive mapping to causal inference, placing generative models at the core of causal explanations for brain function. It inspired to a large degree The Virtual Brain, which builds subject-specific digital twins from multimodal data, enabling brain simulations and exploration. Both frameworks converge at parameter estimation, where model and data meet, providing the mathematical manifestation of cause-effect in pathophysiology.
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