Researchers train sheep to take awake MRI scans

Magnetic resonance imaging (MRI) is a technique often used to study the brains of sheep. Until now, it was only performed under general anesthesia, to ensure the immobility of the animal. However, anesthesia leads to stress and other negative side effects, in addition to jeopardizing the study of brain activity.

A research team from INRAE ​​​​has developed a training protocol adapted to sheep to perform MRI scans on animals while they are awake, without having to be restrained. To do this, researchers have relied on previous work with dogs, which until now have been the only species capable of performing this type of protocol.

In the nursery of the Animal Physiology Facility experimental research unit (UEPAO), located at the INRAE ​​​​Val de Loire centre in Nouzilly, researchers began a habituation phase as soon as the lambs were born. The aim was to identify which animals were most receptive to petting or to having foam objects placed near their heads.

The article was published in the magazine Behavioral research methods.

After selecting 10 lambs, a first training phase took place at the Nouzilly sheep farm. The research team trained the animals to climb a ramp to reach a fake MRI scanner and then lie down. The lambs were also taught to place their heads in a fake MRI coil.

Once they got into the real MRI room, the sheep were able to reproduce the same behavior with ease, but they did have some difficulty remaining completely still. It took a few weeks for the animals to get used to the vibrations of the machine and stop moving for a few minutes. Eventually, the MRI images of their brains were comparable to those of anesthetized sheep, a goal that was initially achieved in six of the ten sheep trained at the time of writing, and has now been achieved in nine sheep. The protocol took nine months, from the birth of the lambs to the first MRI images.

The success of this protocol already opens up new avenues for animal neuroimaging (e.g. fMRI) research—as it allows studying brain functions in awake animals. A study of the activation of certain brain areas in relation to hearing is currently underway and is the subject of a PhD thesis based on this training protocol.

This example of voluntary cooperation between trainer and sheep illustrates the animal’s ability to learn and underscores the importance of human-animal relationships in developing innovative methods. The study also opens up new possibilities for training other animals to perform awake MRI scans. Such training methods could have numerous other applications, in areas such as shearing or medical training, where the animal learns to cooperate during veterinary care.