Interactions with Dogs Linked to Increased Prefrontal Brain Activation in Healthy Subjects

by | Dec 1, 2022 | 2022, Alternative Therapies

Written by Taylor Woosley, Staff Writer. Results of the controlled, within-subject crossover study show that O2Hb was 0.80 µmol/l higher in the presence of the dog compared to in the presence of the plush animal (CI=0.27-1.33, p=.004).

petting dogThe belief that “pets are good for human health” is increasing in popularity, with studies reporting that animal ownership has benefits for the individual1. In particular, there is evidence that pet ownership is associated with better emotional regulation and improved executive functioning2. Animal-assisted interventions use methods including multisensory stimulation, imitation, physical contact, play, and stress reduction3.

Dog-human interactions is associated with decreased agitation and thought to cause at least temporary cognitive improvement, while helping improve social interaction4. Research shows that animals can trigger positive emotions which can potentially enhance neuronal plasticity and improve episodic memory and learning5. The participation of therapy dogs shows positive results in healthcare settings by helping to generate a more relaxed environment that favors communication and improves participants’ ability to focus and engage during the treatment process6.

Marti et al. conducted a controlled trial to investigate brain activation in the prefrontal cortex of healthy human subjects with functional near-infrared spectroscopy (fNIRS). fNIRS has been used as a noninvasive technique to measure brain activity (percent oxygen saturation (%) and total hemoglobin concentrations (tHb)) within human-animal interactions. Different forms of interactions with a dog and with a plush animal were used for comparison. The study had a within-subject crossover design with repeated measures. Subjects were observed and measured during six sessions, consisting of three sessions with a live dog and three control sessions with a plush animal over the course of 2 weeks. The dogs used in the study were trained to work with patients in hospital settings. For the control sessions, a lion plush animal was utilized. Participants (n=19, 9 women and 10 men, mean age of 32.4 years) were included in the trial. During the sessions, participants sat on a therapy couch and had two fNIRS sensors attached to measure oxygen saturation. Additionally, heart rate and electrodermal activity were recorded.

Each session consisted of five 2-minute phases, with the first phase serving as a baseline with the subject in a relaxed, neutral state. In the second phase, participants watched a dog or plush animal from a distance. Then, the dog or plush was placed on a mat on a table. Phase four consisted of the dog or plush laying down next to the participant on the couch. Next, the subject pet the dog or plush animal. Afterwards, there was a second neutral phase with the participant staring at a white wall in a relaxed state. Each phase concluded after 2 minutes. For all participants, three sessions were scheduled in the morning and three in the afternoon to control for time of day.

On average, each participant was analyzed based on 2.89 control sessions and 2.84 dog sessions. Significant findings of the controlled study are as follows:

  • Oxygenated hemoglobin (O2Hb) in the prefrontal lobe increased significantly from phase neutral 1 to phase petting by 2.78 µmol/l (CI=2.03-3.53, p<.001). After removal of the stimulation in phase neutral 2, O2Hb stayed constant and was still significantly higher compared to phase neutral 1 (estimate = 2.91 μmol/l, CI = 2.16–3.65, p < .001).
  • Regarding deoxygenated hemoglobin (HHb), when stimulation increased, HHb in the prefrontal lobe decreased significantly from phase neutral 1 to the petting phase by 1.23 µmol/l (CI = −1.75 to −0.72, p=.003). After removal of the stimulation in phase neutral 2, HHb stayed constant and was still significantly lower compared to phase neutral 1 (estimate = −1.20 μmol/l, CI = −1.72 to −0.69, p=.005).

Results of the study show that an increase was observed in prefrontal activity with increased intensity of contact with a dog or plush animal. The brain activity was higher when subjects interacted with a dog compared to the plush animal. Further studies should continue to explore changes in brain activity during human-animal interactions. Study limitations include the inability for blinding due to the nature of the study, the addition of another person (dog trainer) being present during the sessions, and the lack of assessing attitudes towards animals.

Source: Marti, Rahel, Milena Petignat, Valentine L. Marcar, Jan Hattendorf, Martin Wolf, Margret Hund-Georgiadis, and Karin Hediger. “Effects of contact with a dog on prefrontal brain activity: A controlled trial.” Plos one 17, no. 10 (2022): e0274833.

© 2022 Marti et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Click here to read the full text study.

Posted December 1, 2022.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

  1. Shoesmith E, Shahab L, Kale D, et al. The Influence of Human-Animal Interactions on Mental and Physical Health during the First COVID-19 Lockdown Phase in the U.K.: A Qualitative Exploration. Int J Environ Res Public Health. Jan 22 2021;18(3)doi:10.3390/ijerph18030976
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  6. Rodrigo-Claverol M, Malla-Clua B, Marquilles-Bonet C, et al. Animal-Assisted Therapy Improves Communication and Mobility among Institutionalized People with Cognitive Impairment. Int J Environ Res Public Health. Aug 14 2020;17(16)doi:10.3390/ijerph17165899