Figure 2.

Positive feedback loops between microbiome diversity and cognition. A highly diverse microbiome improves memory and behavioural flexibility and associated foraging success, and as a result, dietary breadth maintains a diverse microbiome. By contrast, low microbial diversity impairs cognitive abilities, resulting in poor foraging success. However, the gut microbiome can influence host food preferences and reward valence as a means to increase microbial diversity, and to improve learning and memory for food sources, breaking out of the positive feedback loop (black arrow). Finally, individual differences in cognition (specificity versus generalization), competitive ability and innovativeness influence diet. Arrows represent directional influences on, or in response to, phenotypic traits (represented within grey boxes).