Effects of contact with a dog on prefrontal brain activity: a controlled trial

Background There is a broad range of known effects of animal contact on human mental and physical health. Neurological correlates of human interaction with animals have been sparsely inves- tigated. We investigated changes in frontal brain activity in the presence of and during con- tact with a dog. Methods Twenty-one healthy individuals each participated in six sessions. In three sessions, partici- pants had contact with a dog, and in three control sessions they interacted with a plush ani- mal. Each session had five two-minute phases with increasing intensity of contact to the dog or plush animal from the first to the fourth phase. We measured oxygenated, deoxygenated, and total hemoglobin and oxygen saturation of the blood in the frontal lobe/frontopolar area with functional near-infrared spectroscopy (SenSmart Model X-100) to assess brain activity. Findings In both conditions, the concentration of oxygenated hemoglobin increased significantly from the first to the fourth phase by 2.78 μmol/l (CI = 2.03-3.53, p < .001). Oxygenated hemoglo- bin concentration was 0.80 μmol/l higher in the dog condition compared to in the control con- dition (CI = 0.27-1.33, p = .004). Deoxygenated-hemoglobin concentration, total hemoglobin concentration, and oxygen saturation showed similar patterns. Conclusion Prefrontal brain activation in healthy subjects increased with the rise in interaction closeness with a dog or a plush animal. Moreover, interaction with a dog stimulated more brain activity compared to the control condition, suggesting that interactions with a dog can activate stron- ger attentional processes and elicit more emotional arousal than interacting with a nonliving stimulus.