Gut Microbiota: A Modulator of Brain Plasticity and Cognitive Function in Ageing

Abstract

Gut microbiota have recently been a topic of great interest in the field of microbiology, particularly their role in normal physiology and its influence on human health in disease. A large body of research has supported the presence of a pathway of communication between the gut and the brain, modulated by gut microbiota, giving rise to the term "microbiota-gut-brain" axis. It is now thought that, through this pathway, microbiota can affect behaviour and modulate brain plasticity and cognitive function in ageing. This review summarizes the evidence supporting the existence of such a connection and possible mechanisms of action whereby microbiota can influence the function of the central nervous system. Since normalisation of gut flora has been shown to prevent changes in behaviour, we further postulate on possible therapeutic targets to intervene with cognitive decline in ageing. The research poses various limitations, for example uncertainty about how this data translates to broad human populations. Nonetheless, the microbiota-gut-brain axis is an exciting field worthy of further investigation, particularly with regards to its implications on the ageing population.

Keywords: adult hippocampal neurogenesis; ageing; cognitive function; fatty acids; gut microbiota; gut-brain axis; inflammation; probiotics.

Figure 1

A summary of the various possible mechanisms by which microbiota can affect CNS function together with possible treatment strategies to prevent changes in behaviour and cognitive function in ageing. SCFA: short chain fatty acids; CNS: central nervous system.