Stroking a Real Horse Versus Stroking a Toy Horse: Effects on the Frontopolar Area of the Human Brain

The effects of animal-assisted therapy (AAT) on human cerebral activity are not clearly understood, although many studies have reported psychological and physiotherapeutic benefits associated with it. Any benefits of AAT are likely to be closely related to brain activity. The aim of the present study was to investigate the effects of stroking a horse on brain activity in humans, specifically the frontopolar area, to evaluate the significance of using real animals in AAT. In a randomized cross-over trial, 30 healthy adults saw and stroked a stuffed toy (Session T) followed by a miniature horse (Session A), or vice versa. Participants saw and stroked the object (the stuffed toy or the real animal) for 10 minutes, followed by seeing and stroking another object (the real animal or the stuffed toy) for 10 minutes, with 20 minutes for measurements and resting. We measured changes in oxygenated hemoglobin (oxy-Hb) in the frontopolar area using near-infrared spectroscopy (NIRS). Three-way repeated measures ANOVA was used to compare oxy-Hb changes between the object used (stuffed toy versus real animal), contact method (see versus stroke), and laterality (left versus right). Oxy-Hb changes were larger in the right frontopolar area compared with those in the left frontopolar area when participants stroked a real horse (p < 0.05). Binominal tests showed that, in participants who reported that they "loved horses," the laterality of oxy-Hb changes when participants stroked a real horse was significant (p = 0.031), but this was not seen in those who reported that they only "kind of liked" horses. These findings suggest that stroking a real horse activates the right frontopolar area, but this effect is not achieved when stroking a stuffed toy. Using horses in AAT that aims to activate human brain activity could be useful.