Frequently asked questions

The triangular LABORAS platforms are about 72 cm x 72 cm x 102 cm (28.3" x 28.3"x 40.2"). By placing the platforms in a space efficient way, the amount of space required for LABORAS is very acceptable. For example 3 platforms and the LABORAS control unit can be fitted on a table of 80cm x 170cm. It is advised to use table tops that are at least 80cm deep, to prevent that LABORAS platforms are extending beyond the table top. Possible configurations are given in the following document:

Setup LABORAS Platforms

The Laboras platforms are designed in such a way that they can be fitted with two types of cages: Type-IIIh for rats and Type-II for mice. The cages have a top with food hopper and water bottle. The cages are included with the LABORAS system. Extra cages can be ordered with the LABORAS system or later on. In addition special cages and cage inserts are available to create a light-dark cage for mice or rats and a Socoiability Cage for mice.

The main difference is that LABORAS measures and analyzes the force or energy that is induced by the movements of the animal and derives from this the behavior of the animal. Video based system use the position of the animal and some of these systems the "posture" of the animal to recognize the behavior. Because all behaviours are basically a translation from potential to kinetic energy, energy is a more direct parameter than the posture of the animal. In addition, the energy parameter is much easier to capture and analyze than the posture of the animal. A video signal is a very limited presentation of what is really happening, because only a part of the animal is visible in the signal. The other problem is that the signal is deteriorated by many factors (no light during lights-off periods, focus of camera, resolution of image, etc.). In the ideal situation the video signal is also a very complex signal to use for automatic recognition of behavior.
A detailed comparison is given in the following presentation:

Comparison with the competition

Although there are not very stringent requirements for the use of LABORAS, the tables must be constructed in such a way that they can support the weight of the heavy LABORAS platforms. It means that solid and stable tables must be used that are supported by table legs on the front and backside to prevent oscillations and bending of the table top. It is advised to bend air flows from air conditioning systems away from the LABORAS platforms or to make the airflow more diffuse. More information can be found in the document below:

Environmental conditions

LABORAS is validated for the following weight ranges:
Mice: 15 - 60 grams
Rats: 80 - 700 grams
However, the design allows wider weight ranges. If your animals are outside the above mentioned weight ranges, please contact us for more possibilities.

LABORAS is completely modular. The LABORAS system is suited for rats and mice. So, if you buy a system for rats, it can later be expanded to mice by buying the right software modules and the mouse cages. The same applies for the number of platforms and special behavior detection modules. Extra measurement platforms can be easily added. Metris will send you the new software and a new license key that will give you access to the additional functionality.

In addition Metris is continuously developing new modules for the detection of special behaviors. More information about our developments and the current functionality of the LABORAS system can be found on this website.

There are a number of things to keep in mind when selecting a system for recording of Ultrasonic Vocalizations:
1) The sensitivity of the microphone is crucial to record the ultrasonic vocalizations (USV's) with a proper signal to noise ratio and enable further in-depth analysis of the recording. There are several types of microphones available. Always choose an electrostatic microphone of wich the sensitivity is extended by using an offset voltage. Chip based microphones are not very sensitive and easily damaged by moisture or high humidity.
2) The electronics and analog to digital convertors should have a very good signal to noise ratio to prevent that noise is added to the recorded signals.
SonoTrack applies the latest amplifier technology to reduce noise to an absolute minimum and uses superior data acquisition boards of National Instruments.
For reliable recording and analysis of all USV calls a full spectrum system is not just an extra system function, it is a requirement in any experiment using USV calls. By using full spectrum recording and a system with a high sensitivity and good microphones, not only all calls are recorded, but they are also recorded without distorting the original USV calls.

It's not always necessary to use sound proof chambers. It is strongly depedent on the background noise in the laboratory room. The SonoTrack system uses filters to remove all sounds below 15 kHz and all sounds above 125 kHz. So, effectively only sounds in the ultrasound range will be picked up. Secondly, the microphones are directional. It means that ultrasound noise from the environment is strongly reduced. Finally SonoTrack has the possibility to filter out ultrasound interference. Most sources of interference can be easily recognized because the interference is often concentrated in a very small frequency band.

However, it is important to think carefully about the setup of your experiment, such as the cages and the placement of the microphones. Ultrasounds are easily reflected. It is often advisable to use a plate of sound absorbing material above the cage with the animal. The microphone can be mounted in the plate in such a way that it is looking downwards. If your experiment requires recording of several cages at the same time, it is advisable to use sound attenuation chambers, such as our product SmartChamber or as a minimum sound absorbing plates between the cages, such that sounds from one cage are not reaching the other cage. SonoTrack has the possibility to adjust the amplifier of each channel individually. So, if sounds of one cage reach another cage, it is possible to reduce the sensitivity. When counting calls automatically in SonoTrack, the automatic call counter has an adjustable threshold level which enables you only to count USV calls that exceed the threshold level.

SonoTrack offers the possibility to chain several microphones together. The microphones will effectively operate as one microphone. When coupling microphones together the sensitivity of the microphone will be reduced. This is not a problem in SonoTrack: The high sensitivity and low noise of the SonoTrack system enables you to increase the gain of the amplifiers, without getting problems with system noise.

The SleepSign data acquisition program can record up to 16 channels with the standard hardware setting. With additional hardware; channel expansion accessory, you can record up to 32 channels. Therefore, if you record two channels (EEG and EMG) from each animal, you can record up to eight animals with the standard hardware setting, and 16 with the channel expansion accessory.

If you add video recording capability, you can record/playback up to 4 animals using a multiplexer. (SleepSign supports multiplexers which divide the image into four parts). You can record up to 16 channels of waveform data when you record video, too.

Below the raw data file sizes are given when you record for 24 hours.

Although the majority of our clients use SleepSign for studies with rodents, you can apply it to any kind of animal as long as EEG and EMG are available. However, the auto-scoring might not work well if the transition in EEG and EMG among each sleep/wake stages is very subtle or not observed.

Currently, we have not applied for the medical equipment approval from the FDA since we are focusing on supporting researchers who work in basic animal research. Although SleepSign has more than enough capability to analyze human sleep as well, we prohibit using SleepSign for human analysis at the moment.

SleepSign supports the following sorts of digital data format:

SleepSign supports Dataquest A.R.T. version 2.1, 2.2, 2.3, 3.0

• BioPac AcqKnowledge data files
• European Data Format (EDF) files * SleepSign does not support EDF+ * SleepSign does not support EDF files which are recorded with Electro mode. Please contact us for more detail.
• Text files (ASCII or CSV)

You can select suitable epoch length from the following choices: 4, 8, 12, 5, 10, 15, 20, 30, 60 (sec).

If you differentiate by three stages (Wake, REM, NREM), the average agreement between auto-scoring and your manual scoring will be approximately 90% for Rats. However, if the transition of EEG and EMG between each stage is very subtle or not observed, the auto-scoring may not work properly.