Scientists from the US Department of Energy national laboratories have found that particular gut bacteria can improve the memory of mice.
In the study, the researchers used a mouse model known as the Collaborative Cross. The model which included a wide variety of mouse strains intended to imitate the genetic distinction found in humans.
Initially, each strain of mice was given a memory test. After which, the researchers searched for the genetic characteristics present in the mice obtaining highest scores on the tests.
Two sets of genes were found to be linked to the mice's memory abilities, while one set of 135 genes had not been previously associated with memory or cognition.
After this, the researchers studied the gut genetic makes up of each of the different mouse strains. Lactobacillus was the prevailing family of microbes discovered to be related to better memory.
Simultaneously, L. reuteri was found to be most correlated with memory among all the other bacteria explored. To have a better understanding of the bacteria, the researchers distributed the bacteria to mice who were free of germs.
The memory tests confirmed that the bacteria contributed to improving the mice's memory in comparison to germ-free mice who received other microbes.
The researchers also analyzed the metabolites in certain gut bacteria to understand how they improved memory. They discovered that lactate was produced in large amounts. The team them concluded that feeding lactate to mice with poor memory led to meaningful improvements in their memories.
Improving the Memory in Mice
According to Antoine Snijders, a bioscientist at Lawrence Berkeley National Laboratory and one of the authors of the study, it was challenging to conduct the experiment since a mouse's genetic makeup, and environmental conditions made an impact on its memory and microbiome.
Snijders added that to be certain if a microbial molecule influenced memory, they needed to understand the interplay between genetics and the microbiome. While a connection between Lactobacillus and memory was already previously established, the team also found it individually in the impartial genetic screen.
He added that the results of their study propose that genetic alterations in big parts control memory. Similarly, so do differences in the makeup of the gut microbiome across strains.
The microbiome's effect on memory is currently very active in the field of research, he added. There are more than 100 papers published in the last five years on links between common probiotics and memory.
Among the papers published on the subject is a study entitled 'Lactobacilli and bifidobacteria ameliorate memory and learning deficits and oxidative stress in β-amyloid injected rats'. The findings of the paper claimed that probiotics play a role in improving memory deficit and stopping the pathological mechanisms of Alzheimer's disease in mice by modifying microbiota.
Janet Jansson, a co-author of the study, says that their research manifests that the microbiome could partner with genetics to affect memory. However, she says that more research needs to be done to show if Lactobacillus can genuinely improve the memory of humans.
