This page lists techniques and measurements employed by
the easyTEL+ system for rodents, and used in the area
of measuring cardiovascular, neurological and respiratory
outcomes.
Physiological measurements are captured, amplified and digitized by a transmitter
surgically implanted and wirelessly transmitted to a receiver within 3 to 5 meters distance.
When received by the telemetry receiver, physiological signals can directly be sent to the acquisition computer, via Ethernet.
Communication between implants and receivers is bidirectional, allowing data collections, but also implant remote control (implant state (on/off), settings and configuration).
Telemetry technique ensures no cross talk between transmitters, allowing
animals to be group-housed in the same room or cage.
Electrocardiogram (ECG), electroencephalogram (EEG), electromyogram (EMG) or
electrooculogram (EOG) signals can be retrieved using digital telemetry easyTEL+ through implanted electrodes. Various configurations are available:
Single lead biopotential, using a 2-wire electrode:
To get 1-lead ECG, or 1 EEG, EOG or EMG. For ECG, Lead II placement is usually
chosen (but not necessarily).
Dual biopotential:
To get a 2-lead ECG or a combination of 2 biopotentials amongst 1-lead ECG, EEG,
EOG or EMG.
Unipolar configuration, using 3 wires electrode:
In this configuration, the reference electrode is common to both biopotentials.
Unipolar biopotential is easier for the surgery but both biopotentials must be similar (2 EEG or 2 ECG for instance).
Bipolar configuration, using 4 wires electrodes:
In this configuration, the biopotential is measured between the positive (red) and
negative (white) electrode, allowing to get two independent biopotentials (EEG and
EMG for instance).
ECG : wave duration, amplitude, ST elevation, QT correction , arrythmia detection,
HRV analysis.
EMG : Temporal and spectral analysis
EEG :
• Sleep scoring
• Epileptic seizure detection
• Spectral analysis
EOG : Temporal and spectral analysis
Intra‑arterial blood pressure (BP) measurement is the gold standard for obtaining high‑fidelity cardiovascular data in rats.
Blood pressure can be monitored directly and continuously in conscious, freely moving animals, over an extended period.
Implants are equipped with a miniature catheter designed to be surgically inserted into a suitable artery, such as the femoral or carotid for example.
Intrapleural implantation of telemetry pressure probes was found to be a reliable modality to monitor changes in breathing rate and general breathing mechanics, as shown in this poster:
Breathing rate can be retrieved from easyTEL+ implants through:
• Blood pressure low frequency variations
• Pleural pressure frequency
• Diaphragmatic EMG low frequency variations
A 3-axis accelerometer inside the implant measures the acceleration in the x-, y- and z-axis.
Any movement of the subject head translates in variations in the x, y, z coordinates of acceleration.
Using the three individual axis signals, IOX2 acquisition software calculates a global acceleration, making it possible to derive information about the animal’s posture (standing on hind legs, on its side etc).
The easyTEL+ implant houses a cutting-edge sensor that continuously monitors core body temperature with a resolution of 0.04°C.
