Animal Positioning

Animal Positioning to Avoid Movement Artifact

Animal movement creates biological noise in ERG or VEP recordings. Most movement artifacts are caused by the animal's breathing. Sometimes, gas anesthesia can cause gasping which is difficult to minimize. Other times, however, movement artifacts from normal breathing can be eliminated by stretching the body of the animal so that the neck is not affected by the movement of the lungs.

An animal whose rib cage and neck are squished together will inadvertently move its neck when breathing. This type of movement interferes with ERG/VEP recordings. In order to create a stable eye-to-electrode connection, elongate the animal's body to create space for the breath to flow into the abdominal cavity. 

Animal Positioning Technique 

The key to both techniques is to be very gentle in order to avoid spinal damage!

• Technique #1: Place the mouse down towards the back of the headrest and gently drag it forwards onto the headrest. 
• Technique #2: Place the mouse slightly in front of the headrest and use the tail to gently pull its body backwards into position.