Publications by authors named "Takefumi Kikusui"

Emotional contagion occurs in many animals, including rodents. To determine the social signals of emotional state-matching between individuals in mice, we conducted an empirical laboratory experiment using visual, olfactory and auditory stimuli. The Japanese wild-derived mouse strain MSM/Ms (MSM) was tested as observers, since our initial experiments indicated that MSM mice showed higher sensitivity to others' pain compared with the laboratory strain C57BL/6J (B6).

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  • Copy number variants (CNVs) are linked to psychiatric disorders and brain structure changes, but the specific gene effects within the CNV regions, like 22q11.2, are still unclear.
  • This study focuses on Tbx1, a gene in the 22q11.2 region, exploring how it influences brain volume and behaviors through a detailed analysis of Tbx1 heterozygous mice using magnetic resonance imaging.
  • Results showed decreased volumes in key brain areas associated with social behavior and learning, while some auditory regions were larger, highlighting the nuanced impacts of Tbx1 on brain structure and function.
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Behavioral and physiological synchrony facilitate emotional closeness in attachment relationships. The aim of this pseudorandomized cross-over study was to investigate the emotional and physiological link, designated as co-modulation, between dogs and their owners. We measured the heart rate variability (HRV) and physical activity of dogs belonging to co-operative breeds (n = 29) and their owners during resting baselines and positive interaction tasks (Stroking, Training, Sniffing, Playing) and collected survey data on owner temperament and dog-owner relationship.

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Introduction: The One Health concept is a comprehensive understanding of the interaction between humans, animals, and the environment. The cohabitation of humans and pets positively affects their physical, mental, and social well-being. It is recognized as an essential factor from the One Health perspective.

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It is well known that dogs are capable of following human verbal instructions. However, very little is known about the equivalent ability in cats. In this study, we used a switched stimuli task to examine whether cats rapidly form picture-word association, which is a fundamental ability for word learning.

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  • The study investigates the role of oxytocin in emotional contagion and how it affects fear-related behaviors in mice with different oxytocin receptor expressions.* -
  • In experiments, wild-type mice exhibited vicarious freezing when observing others in fear, while mice with reduced or absent oxytocin receptors showed less of this behavior.* -
  • The findings suggest that oxytocin is important for recognizing others' emotions and responding to them, but does not affect fear responses in non-social contexts.*
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  • - Early weaning (EW) in mice leads to increased anxiety and stress responses in adulthood, affecting both behavior and immune function.
  • - Mice subjected to EW showed significant differences in behavior tests compared to normally weaned (NW) mice, along with notable changes in their gut microbiome composition, specifically reduced Erysipelotrichaceae.
  • - Germ-free mice colonized with gut microbiota from EW mice exhibited higher depressive behaviors and altered immune cell profiles, indicating that changes in gut microbiota due to EW can influence mood and immunity.
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The sleep-wake cycle represents a crucial physiological process essential for maintaining homeostasis and promoting individual growth. In dogs, alterations in sleep patterns associated with age and dog's correlation with temperament factors, such as nervousness, have been reported, and there is an increasing demand for precise monitoring of sleep and physical activity in dogs. The present study aims to develop an analysis method for measuring sleep-wake patterns and physical activity in dogs by utilizing an accelerometer and a smartphone.

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Changes in the mother-offspring relationship are presumably accompanied by dynamic changes in the autonomic nervous system. Although temporal measurements of autonomic activity have been performed in human mothers and infants, the analysis of long-term changes remains unexplored. Mouse mothers can form social bonds with their pups and have a short period of pregnancy and lactation, which makes them useful for the examination of physiological changes from pregnancy to pup-rearing.

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This study investigated the relationship between urinary hormone concentrations and attachment-related behaviors in two dog breeds, the Akitas and Labrador Retrievers, to elucidate the hormonal and behavioral mechanisms underlying domestication and interspecies attachment to humans. By measuring cortisol and oxytocin concentrations, and conducting the Strange Situation Test (SST), we aimed to investigate breed differences in endocrine secretions associated with domestication and how these differences influence dog behavior toward humans. Our results showed significant breed differences in urinary cortisol concentrations, with Akitas exhibiting higher levels than Labrador Retrievers.

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The number of mothers suffering from mental illness is increasing steadily, particularly under conditions of the coronavirus pandemic. The identification of factors that contribute to resilience in mothers is urgently needed to decrease the risks of poor physical and psychological health. We focused on the risk of parenting stress and psychological resilience in healthy mothers with no psychiatric and physical disorders and conducted two studies to examine the relationships between intestinal microbiota, physical condition, and psychological state.

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The matrilineal transmission of maternal behavior has been reported in several species. Studies, primarily on rats, have suggested the importance of postnatal experience and the involvement of epigenetic mechanisms in mediating these transmissions. This study aims to determine whether the matrilineal transmission of maternal behavior occurs in mice and whether the microbiota is involved.

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  • Building friendly relationships is key for good mental health, and robots may help in this area, though evidence is limited.
  • Studies showed that people who own companion robots had higher levels of oxytocin and displayed more intimate behaviors compared to those without robots.
  • Interaction with robots, even for just 15 minutes, lowered stress hormone cortisol in both groups, indicating that robot relationships can positively impact mental health.
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  • Mice form social groups for survival, and understanding their interactions is key to studying group behavior, specifically huddling, which hasn't been analyzed in-depth.
  • This study introduces a cost-effective method using OpenCV for long-term monitoring of huddling behavior by representing mice as 'blobs' in video frames, significantly reducing data storage needs.
  • The algorithm showed over 90% accuracy when compared to manual cluster counting, and initial findings hint at gender differences in huddling, paving the way for further research into group behavior in neuropsychiatric disorders.
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Introduction: Late adolescence is a crucial period during which individuals connect with new communities. Furthermore, their mental health has lasting effects on their overall well-being. Involvement with family and the local community plays a significant role in shaping adolescents' personalities and well-being.

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  • Copy number variants (CNVs), especially those in the 22q11.2 region, are linked to psychiatric disorders and brain structure changes, but the exact relationship between specific genes and these issues isn't fully understood.
  • This study focuses on a gene within the 22q11.2 CNV, suggesting it plays a significant role in social interaction, memory, and cognitive flexibility.
  • Using brain imaging in mice with this genetic variant, researchers found reduced volumes in certain brain areas and linked these changes to difficulties in social interactions, highlighting the impact of genetic loss-of-function variants.
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Physical and mental effects stemming from COVID-19 have impacted not only people's lives but also the lives of their pets, which in recent years are often seen as members of the family. This study aimed to explore the impact of the COVID-19 pandemic in Japan on pets and their owners. Participants reported changes in physical activity and mental health, as well as working conditions and frequency of interaction with pets, before and after behavioural restrictions due to the COVID-19 pandemic.

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Copy number variants (CNVs) are robustly associated with psychiatric disorders and their dimensions and changes in brain structures and behavior. However, as CNVs contain many genes, the precise gene-phenotype relationship remains unclear. Although various volumetric alterations in the brains of 22q11.

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  • The study compares the bond between dogs and humans to the attachment between mothers and infants, focusing on how dogs' attachment behaviors affect their owners.
  • Researchers assessed heart rate variability in both dogs and owners during a specific test to see if eye contact from dogs decreased the owner's parasympathetic activity, indicating a stress response.
  • Results showed that dogs had lower parasympathetic activity when gazing at their owners compared to strangers, but the study did not confirm if this gaze impacted humans' autonomic activity as a sign of attachment.
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Individual differences in the sociality of cats are influenced by inherited and environmental factors. We recently revealed that hormones can make a difference in intraspecies social behavior. It remains unclear whether cat behavior toward humans is modulated by hormones.

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Previous studies have demonstrated that paternal caregiving behaviors are reliant on neural pathways similar to those supporting maternal care. Interestingly, a greater variability exists in parental phenotypes in men than in women among individuals and mammalian species. However, less is known about when or how such variability emerges in men.

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We aimed to clarify the changes in facial morphology of cats in relation to their interactions with humans. In Study 1, we compared the facial morphology of cats (feral mixed breed, owned domestic mixed breed, and owned domestic purebreds) with that of African wildcats. After collecting 3295 photos, we found that owned domestic cats' noses were significantly shorter than those of African wildcats and feral mixed breed, and there were no significant differences between the latter two.

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Common marmosets have been widely used in biomedical research for years. Nutritional control is an important factor in managing their health, and insect intake would be beneficial for that purpose because common marmosets frequently feed on insects in natural habitats. Here, we examined the effect of enhanced insect feeding on the gut by analysing the faecal microbiota and transcripts of captive marmosets.

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We examined whether dogs show emotional response to social stimuli played on videos. Secondary, we hypothesized that if dogs recognize themselves in videos, they will show a different emotional response to videos of self and other dogs. We compared heart rate variability among four video stimuli: a video of the owner ignoring another dog (OW-A-IGN), a video of a non-owner interacting with another dog (NOW-A-INT), a video of the owner interacting with another dog (OW-A-INT), and a video of the owner interacting with the dog subject (OW-S-INT).

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