I cannot say that I have ever given horse brains much thought. Monkey brains, rat brains, even sea slug brains have played a much greater role in our understanding of modern neuroscience. Horses do make at least one appearance in psychology, in the form of the cautionary tale of Clever Hans, who demonstrated that horses are at the very least incredibly sensitive to human body language. If I thought about the horse brain at all, it would have been to wonder if anyone had preserved
And then, on a weekend training session at the therapeutic riding center where I volunteer, one of the therapists mentioned off-hand that a good relationship between horse and rider will change not only the rider’s brain, but the horse’s as well. This led to a very research-scientist moment, as I wondered…just how would anyone determine that a horse’s brain had changed?
Most animal brains studies are done with a post-mortem dissection, which is a fundamentally one-time opportunity; it can tell us what a horse’s brain was like at the end, but not whether that brain structure came from some particular relationship. With a horse rider, we could simply put them in an MRI machine before and after lessons to look for changes in brain structure or in empathy or responses to a horse, but those machines are quite claustrophobic enough for people, and are certainly not designed to fit a horse, sleeping or otherwise.
But there is one method of studying the brain that can, apparently, be adapted to work with horses: the electroencephalogram, or EEG. Small electrodes are placed at various locations on the scalp, to pick up the electrical activity created by our neurons. Apparently, this technique is of great interest to the horse experts, who have used it to estimate the effectiveness of horse anesthesia during surgery, and suggest its use be expanded to understand horse neurology when horses behave badly.
Investigating how horse brains respond to humans, however, seems to be still rather novel. I could find only one study that did so, and it is not properly published; it was made available online through the now-defunct “Nature Proceedings” venue for researchers to share unpublished data. The study, called “The bond between a horse and a human”, placed electrodes on three humans and two horses. The humans were a female college student afraid of horses, a male college student who had ridden once or twice, and a female “horse whisperer”. The horses were one that all three humans were not familiar with, and one of the horse whisperer’s own horses. All three humans had very high scores on a scale to measure bonding with pets, suggesting a high affinity for animals.
Sadly, this unofficial publication is missing the figures referenced in the text. Without the figures, I couldn’t answer my most burning question, which was how a researcher would decide where to put electrodes on a horse brain. The results as well were based on a visual inspection of EEG activity maps while the horse was alone, next to the human, being petted, being groomed, or being sat on. These maps apparently suggest greater “synchronization” of brain activity when a human was grooming or sitting on the horse. In other words, there’s some amount of overlap in the way that the horse’s neurons are firing during these activities, and the way the human’s are firing – at least, greater overlap than when they are separate, or just standing next to each other. This synchrony was supposedly even stronger when horse and rider had an existing relationship, than when they did not know each other.
Now I am less willing to just accept this study, or other anecdotal reports reference by it, as suggesting that horses will literally sync up with their riders. But the possibilities are fascinating, if we can just get a more rigorous investigation of these EEG patterns in humans and animals as they interact. If nothing else, the mental images are wonderful. For example, somewhere on our campus there is bearded dragon, one student’s official emotional support animal. I would happily take up this line of research just to see my imagined vision of a bearded dragon in an EEG cap become reality.