Summary: Anxious dogs have stronger neural connections between the amygdala and other areas of the brain’s fear network compared to less anxious dogs.
Researchers at Ghent University in Belgium report abnormalities in functional neural networks in dogs diagnosed with anxiety.
Led by Yangfeng Xu (Ghent Experimental Psychiatry Lab, GHEP; ORSAMI) and Emma Christiaen (Medical Image and Signal Processing, MEDISIP), the study shows that anxiety patients have stronger connections between the amygdala and other regions of the brain compared to healthy dogs the fear network.
Published in PLUS ONE on March 15, the findings could also help uncover how functional connections between anxiety-related regions of the brain are altered in human anxiety disorders.
Animal models of anxiety are an important tool in the study of anxiety disorders, and the results can benefit both veterinary and human medicine. However, the many different aspects of anxiety cannot all be effectively studied in the same animal model.
While rodents are often studied, this new study uses the larger brains and cortex of dogs to characterize neural networks associated with anxiety. 25 healthy and 13 anxious dogs were volunteered by their owners and examined using non-invasive functional MRI (fMRI).
The dogs were treated in accordance with all necessary animal welfare guidelines to ensure they did not suffer any adverse outcomes from the study. The researchers examined the resting states of dogs with and without anxiety, compared network metrics and connectivity between groups, and determined their associations with anxiety symptoms.
Resting-state fMRI showed that functional connections between the amygdala and other parts of the fear circuit, particularly the hippocampus, were stronger than normal in fearful dogs.
Within the fear circuit, network metrics, including global and local efficiency, were higher in the amygdala of fearful dogs. Dogs that showed fear and anxiety towards strangers, as well as excitability, were more likely to have brains that showed abnormal network metrics in the amygdala.
The researchers believe their results show that resting-state fMRI is a good tool to study models of anxiety in dogs, and that future studies like these could improve our understanding of how fear-related circuits in the brain are altered in anxious animals. and possibly even people with the condition.
The authors add: “In this manuscript, we constructed functional brain networks using graph theory metrics to compare the differences between anxious and healthy groups of dogs.
“Our findings could provide better insight into the topological organization of the functional brain connectome in anxiety disorders, thus leading to a better understanding of the pathophysiological mechanisms and disease course of anxiety in both animals and humans, and contributing to the development of more personalized and effective therapies.”
About this anxiety and animal psychology research news
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Contact: Press Office – PLOS
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Original research: Open access.
“Network Analysis Reveals Abnormal Functional Brain Circuits in Anxious Dogs” by Yangfeng Xu et al. PLUS ONE
Network analysis reveals abnormal functional brain circuits in anxious dogs
Anxiety is a common disorder in human psychiatric disorders and has also been described as a common neuropsychiatric problem in dogs. Human neuroimaging studies showed that abnormal functional brain networks may be involved in anxiety.
In this study, we expected that similar changes in network topology would also be present in dogs. We performed resting functional MRI in 25 healthy dogs and 13 patients.
The generic Canine Behavioral Assessment & Research Questionnaire was used to assess anxiety symptoms. We constructed functional brain networks and used graph theory to compare differences between two groups. No significant differences in the global network topology were found.
However, when focusing on the fear circuit, the global efficiency and local efficiency were significantly higher and the characteristic path length in the amygdala was significantly lower in patients.
We discovered higher connectivity between the amygdala-hippocampus, amygdala-midbrain, amygdala-thalamus, frontal lobe hippocampus, frontal lobe thalamus, and hippocampal-thalamus, all of which are part of the fear circuit. Additionally, correlations between network metrics and anxiety symptoms were significant.
Altered network measures in the amygdala correlated with stranger-directed fear and excitability; an altered grade in the hippocampus was associated with attachment/attention seeking, trainability, and touch sensitivity; abnormal frontal lobe function was associated with hunting and aggression in familiar dogs; Attachment/attention-seeking correlated with functional connectivity between amygdala-hippocampus and amygdala-thalamus; The aggression of well-known dogs was related to the change in global network topology.
These results could shed light on the aberrant topological organization of functional brain networks underlying fear in dogs.