They worked with the same strain of timid mice that Collins studied, and managed to change the animals’ behaviour by feeding them with a single strain of Lactobacillus rhamnosus – a bacterium commonly used in yoghurts and dairy products. After the mice ingested this strain, known as JB-1, they were better able to overcome anxiety: they spent more time in the exposed parts of a maze, or the centre of an open field.
JB-1
