The brain’s Geppetto—microbes as puppeteers of neural function and behaviour?
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Research on the microbiome and its interaction with various host organs, including the brain, is increasingly gaining momentum. With more evidence establishing a comprehensive microbiota-gut-brain axis, questions have been raised as to the extent to which microbes influence brain physiology and behaviour. In parallel, there is a growing literature showing active behavioural manipulation in favour of the microbe for certain parasites. However, it seems unclear where the hidden majority of microbes are localised on the parasitism-mutualism spectrum. A long evolutionary history intimately connects host and microbiota, which complicates this classification. In this conceptual minireview, we discuss current hypotheses on host-microbe interaction and argue that novel experimental approaches and theoretical concepts, such as the hologenome theory, are necessary to incorporate transgenerational epigenetic inheritance of the microbiome into evolutionary theories.
KeywordsHost behaviour Parasite Commensal Epigenetics Metagenome Host ecology Neurovirus Co-evolution
The Alimentary Pharmabiotic Centre is a research centre funded by Science Foundation Ireland (SFI), through the Irish Government’s National Development Plan (Grant Numbers 07/CE/B1368 and 12/RC/2273). R.M.S. is supported by the Irish Research Council (IRC) through a Government of Ireland Postdoctoral Fellowship (Grant Number GOIPD/2014/355). T. G. D. and J. F. C. are supported by SFI (Grant Number 07/CE/B1368 and 12/RC/2273). T. G. D. and J. F. C. are also supported by the Irish Health Research Board, the Department of Agriculture, Food and Fisheries and Forestry and Enterprise Ireland.
Conflict of interest
R.M.S. reports no conflict of interest. T.G.D. and J.F.C. are principal investigators in the Alimentary Pharmabiotic Centre, University College Cork. The Alimentary Pharmabiotic Centre has conducted research funded by Pfizer, GlaxoSmithKline, Proctor & Gamble, Mead Johnson, Suntory Wellness and Cremo. T.G.D. has been an invited speaker at meetings organised by Servier, Lundbeck, Janssen and AstraZeneca. J.F.C. has been an invited speaker at meetings organised by Mead Johnson, Yakult, Alkermes and Janssen.
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