Wednesday and Thursday of this week I was at a biological physics meeting at St Catherine’s college, Oxford. The highlight for me was a talk by the very distinguished biologist Dennis Bray. It was a lovely talk. He started by mentioning the Blue Brain project – a project to reverse engineer the human brain. By reverse engineer the brain I mean break the brain down into its constituent parts, and then understand how these work and how they fit together to the extent that a working simulation of a whole brain can be made. This is ambitious. Probably too ambitious.

Dennis Bray then went on to show that despite decades of hard work we still cannot completely reverse engineer how the common bacterium E. coli detects and responds to molecules it likes. Bacteria like E. coli can detect molecules they like to consume and then head up concentration gradients in these molecules. As Dennis Bray beautifully explained we understand most but not all of how E. coli does this.

He did not explicitly say that if are finding it so hard to work reverse engineer a bacteria’s sense of smell, then we should have some humility in estimating our ability in understanding something as crazily complex as a human brain. He did not need to. His talk, and this message, was so clear that all the audience understood. I wish I could give talks like that.

A thing we don’t understand about E. coli, is its memory. E. coli continually learns about its environment and stores this information, in a relatively simple way. This memory lasts for at least minutes, and at some level for much longer. How it stores this information and uses it to survive and reproduce better is something we are still working on understanding. But it seems that not only do I have happy memories of the gingerbread sticky toffee pudding I had for Thursday lunch at St Catherine’s, the E. coli in my gut also at least dimly remember it.