Juha-Pekka Niskanen

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A computer program for advanced heart rate variability (HRV) analysis is presented. The program calculates all the commonly used time- and frequency-domain measures of HRV as well as the nonlinear Poincaré plot. In frequency-domain analysis parametric and nonparametric spectrum estimates are calculated. The program generates an informative printable report(More)
Kubios HRV is an advanced and easy to use software for heart rate variability (HRV) analysis. The software supports several input data formats for electrocardiogram (ECG) data and beat-to-beat RR interval data. It includes an adaptive QRS detection algorithm and tools for artifact correction, trend removal and analysis sample selection. The software(More)
To understand the dynamics of progressive brain damage after lateral fluid-percussion induced traumatic brain injury (TBI) in rat, which is the most widely used animal model of closed head TBI in humans, MRI follow-up of 11 months was performed. The evolution of tissue damage was quantified using MRI contrast parameters T(2), T(1rho), diffusion (D(av)), and(More)
The present study was designed to test a hypothesis that functional magnetic resonance imaging (fMRI) can be used to monitor functional impairment and recovery after moderate experimental traumatic brain injury (TBI). Moderate TBI was induced by lateral fluid percussion injury in adult rats. The severity of brain damage and functional recovery in the(More)
Simultaneous electrophysiological and functional magnetic resonance imaging measurements of animal models of epilepsy are methodologically challenging, but essential to better understand abnormal brain activity and hemodynamics during seizures. In this study, functional magnetic resonance imaging of medetomidine-sedated rats was performed using novel rapid(More)
PURPOSE To investigate how kainic acid-induced epileptiform activity is related to hemodynamic changes probed by blood oxygenation level-dependent functional magnetic resonance imaging (BOLD fMRI). METHODS Epileptiform activity was induced with kainic acid (KA) (10 mg/kg, i.p.), and simultaneous fMRI at 7 Tesla, and deep electrode local field potential(More)
The aim of this study was to explain the temporal variations between subjects in the blood oxygenation level-dependent (BOLD) response. Somatosensory responses were elicited with the electrical forepaw stimulus at a frequency of 10 Hz in urethane-anesthetized rats, and functional magnetic resonance imaging (fMRI) with BOLD contrast and local field potential(More)
Ventricular repolarization duration (VRD) is controlled by neural regulatory system same way as heart rate and, thus, also VRD varies in time. VRD variability is commonly assessed by determining the time differences between successive R and T-waves, i.e. RT intervals. Traditional methods for RT interval detection necessitate the detection of either T-wave(More)
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