Summary: A French research team has developed a protocol enabling sheep to undergo MRI scans while awake and unrestrained, opening new avenues for animal neuroimaging research.

Key Takeaways:

  • Awake MRI Protocol Development: The National Research Institute for Agriculture, Food and Environment has developed a protocol enabling sheep to undergo MRI scans while awake and unrestrained, based on prior work with dogs.
  • Training and Familiarization: Researchers at the INRAE Val de Loire center trained lambs from birth to become familiar with human interaction and mock MRI equipment, leading to successful real MRI scans.
  • Research Implications: The successful protocol allows for new research in animal neuroimaging, including studies on brain function and activation of specific brain regions, exemplified by an ongoing PhD thesis on hearing-related brain activity.

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A research team from the National Research Institute for Agriculture, Food and Environment in France has developed a training protocol adapted to sheep in order to carry out MRI acquisitions in animals while they are awake, without the need for restraint. To do this, researchers drew on previous work with dogs, which until now had been the only animal species capable of carrying out this type of protocol.

Adapting to MRI Scans After Initial Training

In the nursery of the Animal Physiology Facility experimental research unit, located at the INRAE Val de Loire center in Nouzilly, researchers began a familiarization phase as soon as the lambs were born. The objective was to identify which animals were most receptive to being stroked or to having foam objects placed near their heads. The paper is published in the journal Behavior Research Methods.

After choosing 10 lambs, an initial training phase took place at the Nouzilly sheep farm. The research team trained the animals to climb a ramp to reach a mock MRI scanner and then lie down. The lambs were also taught to place their heads in a mock MRI coil. Once they arrived at the real MRI room, the sheep were able to reproduce the same behavior very easily, but had some difficulty remaining perfectly 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.

Ultimately, the MRI images of their brains were comparable to those obtained from anesthetized sheep, a goal that was initially achieved in six out of the 10 sheep trained at the time of writing, and has since been achieved in nine sheep. The protocol lasted nine months, from the birth of the lambs to the first MRI acquisitions. Researchers train sheep to complete awake MRI imaging Sheep performing brain MRI acquisition. A The head position in the sheep RF coil. The head is “blocked” with foam pieces adapted to each individual. A trainer is at the front of the bore with a hand placed on the sheep’s back; B The other trainer sat at the back of the bore, facing the sheep, to maintain visual contact.

New Avenues for Animal Neuroimaging

The success of this protocol is already opening up new avenues for research into animal neuroimaging (e.g., fMRI)—since it makes it possible to study brain function in awake animals. A study looking into the activation of certain brain regions in relation to hearing is currently underway, and is the subject of a Ph.D. thesis that relies on this training protocol.