Powerlab 8 35

Each athlete was asked to sit quietly for 3 minutes before the pulse recording and keep relaxing during the whole measurement process. The optical PPG pulses were digitally recorded from the right middle finger using a PowerLab data collection system (ADInstruments Pty Ltd., PowerLab 8/35, Bella Vista, NSW, Australia) at a sampling rate of 1000 Hz. Since there is significant effect of the finger temperature on the PPG pulse shape [22 ], finger skin temperature was ensured to be around 25°C for each athlete. When the PPG pulse waveforms were satisfactory and stably shown on the monitoring screen, they were saved for 30 s to a computer for further off-line analysis.

The test setting was the same for both protocols. To ensure each participant maintained the same posture throughout the experiment, he/she was asked to sit on a height-adjustable mat table with his/her feet on the LIV platform. The height of the table was adjusted to ensure the angles at ankle and the knee were maintained at 90°. To standardize loading between feet and platform, each participant was instructed to lean on his/her elbows which were placed on the top of the knees. Fig 1 demonstrates the test setting. All participants sat quietly for 10 minutes before the experimental protocol was initiated.
LIV was applied using a platform that vibrated vertically at 30Hz with peak acceleration of 0.4 g (0.22mm peak to peak displacement) for 10 minutes (LiveMD, Marodyne Medical LLC, Tampa, FL). To measure SBF data continuously, an optic probe (CP1T-1000, Moor Instruments, Wilmington, DE) was placed on the right foot. The probe was a combination of laser Doppler flowmetry (LDF) and thermometer. PowerLab 8/35 with LabChart V8 (AD Instruments, Colorado Springs, CO) was used for data acquisition. The probe was placed at the midpoint of the horizontal line drawn between the medial malleolus and the Achilles tendon. Fig 1 demonstrates the placement of the probe for measuring SBF and temperature.

During each session, breathing was continuously recorded using a spirometer. Cardiovascular signals (ECG) were also continuously recorded at 1000 Hz. RR-interval time series were extracted from raw ECG signals^{52 (link)}. Respiration and cardiovascular signals were recorded, digitalized and synchronized using a Power-Lab 8/35 device (Human respiratory kit with spirometer and ECG Bio Amps, ADInstrument^®). Calibrations were performed according to the manufacturer’s instructions before each test on each subject.

Cortical brain slices were placed on an interface recording chamber maintained at 34°C superfused with oxygenated aCSF at 2 mL/min. Ascending cortical inputs were stimulated with a tungsten concentric biopolar stimulating electrode (FHC, ME) at the layer VI-white matter boundary. A recording electrode was placed in layer II-III of the cortex. Signals were recorded using glass micropipettes (resistance ≅ 1 MΩ) and acquired with DP-311 amplifier (Warner Instruments, CT) and digitized with a PowerLab 8/35 (AD Instruments, CO) using LabChart software.

A hemodynamic study was performed two weeks after the last dose of CCl4, a washout period intended to avoid the interference of inflammation associated with acute hepatic injury. The rats were anesthetized with sevoflurane (Abbott Laboratories), and the right common carotid artery and external jugular vein were dissected and canalized using a 24 G Abbocath catheter (B. Braun) and a polyethylene tube (PE50), respectively, to measure the mean arterial pressure (MAP) and the central venous pressure (CVP). Thereafter, a mid-laparotomy was performed and a 24 G Abbocath catheter (B. Braun) was inserted into the ileocolic vein to measure the portal pressure (PP). After 5 minutes of stabilization, blood pressures were registered for 5 minutes using pressure transducers and a multichannel PowerLab 8/35 and Lab Chart Reader software (AD Instruments) for analysis. Body temperature was monitored with a thermometer and maintained at stable levels with a warming pad throughout the experiment.

Vocal responses were recorded and used to verify, offline, the accuracy of the response times reported by Presentation software. A Matlab script that detected a vocal response onset based on the sound envelope of the vocalization showed a high level of concordance with the software voice key. This analysis is located in the Supplementary Material.
Further to this analysis, we calibrated the response times reported by Presentation with PowerLab 8/35 (https://www.adinstruments.com/products/powerlab) that measured the veridical times of the stimulus and response relative to each other. We used this to adjust the two response modalities, subtracting 75.83 ms from the button press and 67.43 ms from the vocal responses. Please refer to “Appendix A” for a description and graphical representation of this calibration procedure.

Mice were anaesthetized with a mixture of ketamine (Ketaset, 100 mg/mL; Zoetis, Berlin, Germany) and xylazine (Xylazin, 20 mg/mL; WDT, Garbsen, Germany). To evaluate portal hypertension, the portal pressure was measured in each mouse. The portal vein was cannulated with a 25-gauge safety-multifly needle (Sarstedt, Nümbrecht, Germany), fixated with a vascular clamp and connected to a highly sensitive pressure transducer. The external zero reference point was placed at the midportion of the animal. The measurements were recorded for at least 1 min on a multichannel computer-based recorder using PowerLab 8/35 and the LabChart Software (Powerlab; ADInstruments, Dunedin, New Zealand). The final value for portal pressure of one biological replicate was determined as the mean in the recorded phase.