Faecal Microbiome Transplants Restore Neuroplasticity to Aged Brains

In June 2026, Chris Simms reported on a study showing that a faecal microbiome transplant could make older brains act young again. The research, which was led by Paola Tognini in Italy, suggests that gut bacteria directly influence brain plasticity.

Brain plasticity refers to the brain's capacity to reorganise itself, a process that is usually most effective during childhood.

To investigate this connection, researchers administered broad-spectrum antibiotics to twenty-one-day-old mice through their drinking water for ten days. This treatment caused severe changes in their gut microbiomes, notably reducing bacterial families like Lachnospiraceae, which produce neuroprotective compounds.

Subsequently, the scientists closed one eye of each mouse for three days to observe how their brains responded to visual stimulation. While the untreated control group displayed normal neuroplasticity, the brains of the antibiotic-treated mice failed to adapt to the closed eye.

Furthermore, RNA sequencing showed that more than one thousand genes in the visual cortex were expressed differently in the treated group. These alterations affected genes responsible for the permeability of the blood-brain barrier and the process of nerve myelination.

In the final phase, researchers transplanted the gut microbiota of thirty-day-old mice into adult mice that were four months old. A control group of adult mice received transplants from other older donors rather than the younger animals.

Following the eye-shutting experiment, only the adult mice that had received the young microbiota demonstrated improved neuroplasticity.

Harriët Schellekens, a researcher in Ireland, noted that these findings suggest the microbiome could be targeted to enhance learning and recovery. However, experts warn that we should not assume these results apply to humans, whose brains and microbiomes are far more complex.