Furst, A. J. | Search bioRxiv

bioRxiv2020

Microbiota control of maternal behavior regulates early postnatal growth of offspring

Maternal-offspring bonding and maturation of maternal behavior is necessary during the early postnatal period of an infant to promote optimal development and growth. The regulation of maternal behavior is multifactorial relying both on sensory cues including auditory and olfactory signals emitted by the infant and received by the mother, as well as proper neuroendocrine responses including that of the oxytocin system. The intestinal microbiota has emerged as a critical regulator of growth and development in the early postnatal period of an individual’s life. While, this is best appreciated in the context of direct interactions between the microbiota and the infant, the microbiota can indirectly influence postnatal growth and development by regulating maternal factors. Here, we describe the identification of an intestinal E. coli strain that is pathogenic to the maternal-offspring system during the early postnatal stage of life and results in growth stunting of the offspring. However, rather than having a direct pathogenic effect on the infant, we found that this particular E. coli strain was pathogenic to the dams by interfering with the maturation of maternal behavior. The poor maternal behavior resulted in malnourishment of the pups and impaired IGF-1 signaling leading to the consequential stunted growth. Our work provides a new understanding of how the microbiota regulates postnatal growth and an additional variable that must be considered when studying the regulation of maternal behavior.Competing Interest StatementThe authors have declared no competing interest.View Full Text

physiology↗

bioRxiv2019

Diffusion Tensor Tractography of Brainstem Fibers and Its Application in Pain

Evaluation of brainstem pathways with diffusion tensor imaging (DTI) and tractography may provide insights into pathophysiologies associated with dysfunction of key brainstem circuits. However, identification of these tracts has been elusive, with relatively few in vivo human studies to date. In this paper we proposed an automated approach for reconstructing nine brainstem fiber trajectories of pathways that might be involved in pain modulation. We first performed native-space manual tractography of these fibers in a small normative cohort of participants and confirmed the anatomical precision of the results using existing anatomical literature. Second, region-of-interest pairs were manually defined at each extracted fibers termini and nonlinearly warped to a standard anatomical brain template to create an atlas of the region-of-interest pairs. The resulting atlas was then transformed non-linearly into the native space of 17 veteran patients brains for automated brainstem tractography. Lastly, we assessed the relationships between the integrity levels of the obtained fiber bundles and pain severity levels. Fractional anisotropy (FA) measures derived using automated tractography reflected the respective tracts FA levels obtained via manual tractography. A significant inverse relationship between FA and pain levels was detected within the automatically derived dorsal and medial longitudinal fasciculi of the brainstem. This study demonstrates the utility of DTI in exploring brainstem circuitries involved in pain processing. In this context, the described automated approach is a viable alternative to the time-consuming manual tractography. The physiological and functional relevance of the measures derived from automated tractography is evidenced by their relationships with individual pain severities.

neuroscience↗