Infant gut microbiome composition is associated with non-social fear behavior in a pilot study

Abstract

Experimental manipulation of gut microbes in animal models alters fear behavior and relevant neurocircuitry. In humans, the first year of life is a key period for brain development, the emergence of fearfulness, and the establishment of the gut microbiome. Variation in the infant gut microbiome has previously been linked to cognitive development, but its relationship with fear behavior and neurocircuitry is unknown. In this pilot study of 34 infants, we find that 1-year gut microbiome composition (Weighted Unifrac; lower abundance of Bacteroides, increased abundance of Veillonella, Dialister, and Clostridiales) is significantly associated with increased fear behavior during a non-social fear paradigm. Infants with increased richness and reduced evenness of the 1-month microbiome also display increased non-social fear. This study indicates associations of the human infant gut microbiome with fear behavior and possible relationships with fear-related brain structures on the basis of a small cohort. As such, it represents an important step in understanding the role of the gut microbiome in the development of human fear behaviors, but requires further validation with a larger number of participants.

Hen raising helps chicks establish gut microbiota in their early life and improve microbiota stability after H9N2 challenge

“…The complex microbiome on and within a host, critically linked with health and well-being, is referred to as the “second genome” of the host [ 1 ]. This “second genome” is not innate, but is derived from microbial dispersal and affects the growth [ 2 , 3 ], immunity [ 4 ], behavior and cognitive abilities of the host [ 5 , 6 ].…”

Recent Advances in Understanding the Structure and Function of the Human Microbiome

“…Fear is an emotional and behavioral response induced by a threat. Fear is considered an evolutionarily conserved mechanism that promotes survival (Carlson et al, 2021;Lau et al, 2021). A recent study found that babies with less balanced gut microbiomes show an increase in fear behavior in comparison to those with more balanced microbiomes (Carlson et al, 2021;Lau et al, 2021).…”

“…Fear is considered an evolutionarily conserved mechanism that promotes survival (Carlson et al, 2021;Lau et al, 2021). A recent study found that babies with less balanced gut microbiomes show an increase in fear behavior in comparison to those with more balanced microbiomes (Carlson et al, 2021;Lau et al, 2021). Gut microbiome communities dominated by Bacteroides at the first year of age are associated with less non-social fear, while the lower abundance of Bacteroides and increased abundance of Veillonella, Dialister, Bifidobacterium, and Lactobacillus were linked to increased fear behavior (Carlson et al, 2021;Lau et al, 2021).…”

Stress and the Role of the Gut–Brain Axis in the Pathogenesis of Schizophrenia: A Literature Review

“…Ref. [ 84 ] showed an association of the human infant gut microbiome with fearful behavior and the microbiome’s relationship with fear-related brain structures. On the other hand, the effects of the gut microbiome on the brain and stress have been reported in animal studies.…”

“…They showed that there were changes in gut microbiota, increases in cytokine expression in the frontal cortex, anxiety-like behaviors, and impaired social behaviors [ 89 ]. The fearful behaviors and related neurocircuitry was changed in animal models, which their gut microbes manipulated [ 84 ]. On the other hand, early life stress can also lead to the gut–brain axis alterations that may contribute to stress-related and psychiatric disorders development in adulthood [ 37 ].…”