Knowledge Base

Check the DanioVision System

Before you start setting up EthoVision XT, you need to check the following:

• Camera: The camera lens should have the correct aperture and must be in focus. The camera must also be correctly configured.
• Anti-Condensation Mechanism: You need to configure this depending on the temperature inside the DanioVision chamber and the desired water temperature around the well plate.
• White Light Stimulus: Configure this when you want to use very low intensities for the DanioVision White Light.
• Well Plates and Petri Dishes: The well plate or Petri dish must be inserted correctly. Always control evaporation in the basin and in the well plate, especially when carrying out long trials (more than 1 day).

Check the Camera Lens

Although the camera and lens are set up before shipment, the settings of the lens can shift during transport. Before you start to work with the DanioVision system, check that the lens is set up correctly by doing the following:

1. The lens you use depends on the video resolution and frame rate you want to use.
2. Insert a well plate or Petri dish in the basin.
3. Create a new EthoVision XT experiment and open the Arena Settings to see the camera image. When water is not present in the basin, the image of the well plate should look overexposed.
4. Check the focus. If the camera image is not in focus, loosen the screw, adjust the focus, and tighten the screw. The camera should be focused on the animals. The distance between animals and camera does not change much between types of well plate and water level in the wells; however, it is always a good idea to check the image before an experiment and adjust the focus until it is optimized.
5. Check the aperture ring. The aperture has been adjusted so that when the basin is filled with water, the video image is optimal for tracking. In the Detection Settings, always check that detection of the larvae is good. If necessary, adjust the aperture to get a better contrast between the larvae and the background.
6. Make sure the camera is correctly configured.

The more the lens aperture is set toward C (Close), the larger the depth of field is. This means that the subject looks sharp across a wider range of distances from the lens. This is especially relevant when working with a zoom lens and zooming in to focus on a smaller region of a well plate. If the aperture is set to O (Open), the subject may look sharp only at a certain water depth.

Closing the aperture has the disadvantage of decreasing the contrast between the subject and the background. Adjust the aperture until the image is optimized.

Configure the Anti-Condensation Mechanism

The Anti-Moisture switch is located behind the camera, on the left side. The DanioVision Observation Chamber is equipped with an anti-condensation mechanism to prevent water droplets from forming on the lens during an experiment. A temperature sensor inside the chamber checks whether the mechanism should be switched on or off when set to Auto mode. Besides Auto mode, you can also permanently switch the mechanism On or Off.

Auto Mode

This is the default and recommended setting when the DanioVision TCU is not used. The anti-condensation mechanism is automatically switched on when the air temperature inside the chamber drops below 28 °C (82.4 °F) to prevent condensation on the lens. When the air temperature exceeds 28 °C, the mechanism is automatically turned off to prevent heating of the water in the wells. The value of 28 °C is a default setting of the embedded controller.

If you use the DanioVision TCU, follow the instructions in the DanioVision Temperature Control Unit section and set the switch to either On or Off.

Off

The anti-condensation mechanism is permanently turned off. Use this mode when the air temperature inside the chamber is equal to or higher than the actual water temperature of the basin or well plate (in most cases 28 °C). This option can be used in combination with the DanioVision TCU.

On

The anti-condensation mechanism is permanently turned on. Use this mode when the air temperature inside the chamber is lower than the water temperature in the wells. This option can be used in combination with the DanioVision TCU.

Configure the DanioVision White Bottom Light

Light Intensities in DanioVision DVOC-0050

In DanioVision DVOC-0050, the White Bottom Light levels are fully adjustable in the EthoVision XT Trial Control Settings using the Action box for the White Light.

Light Intensities in DanioVision DVOC-0041

The intensities of the White Light in DanioVision DVOC-0041 are the same as those of the White Bottom Light in DanioVision DVOC-0050:

• 5% (Step 207): 139 lux
• 25% (Step 1000): 2500 lux
• 50% (Step 2100): 5300 lux
• 75% (Step 3000): 8000 lux
• 100% (Step 4095): 10500 lux

Light Intensities in DanioVision DVOC-0040

The reference values of the intensity of White Light in DVOC-0040 are as follows:

• 1% (Step 40): 70 lux
• 25% (Step 1025): 1450 lux
• 50% (Step 2050): 2950 lux
• 75% (Step 3000): 4400 lux
• 100% (Step 4096): 5450 lux

You may want to replicate light conditions set in DanioVision DVOC-0040 in a new experiment with DanioVision DVOC-0050. For example, if you set light intensity to 50% in DanioVision DVOC-0040, this gave 2950 lux. The equivalent percentage in DanioVision DVOC-0050 would be (2950 / 5300) × 50 = approximately 28%.

To find the percentage P50 to set in DanioVision DVOC-0050, based on the percentage and intensity used in DanioVision DVOC-0040 (P40 and Lux40 respectively), use the following formula:

P50 = (Lux40 / Lux50) × P40

Where Lux50 is the intensity in lux in DanioVision DVOC-0050 corresponding to the percentage set in DVOC-0040.