What Marmite can tell us about brain development – a night at Falmouth Café Scientifique

By one of our Champions, John Chilton

Falmouth Café Scientifique brings scientists face to face with an interested and informed audience with no lectern or Powerpoint to hide behind.  The presenter has 20 minutes to put their case, the audience then has 20 minutes to refresh themselves at the bar whilst coming up with fiendish questions to fill the next 90…

Twenty minutes is tricky, it’s not so short that you can whizz through and excuse your lack of depth due to time constraints.  It’s not long enough that you can afford to waste time with digressions or droning.  All in all, it’s the sort of thing that we don’t like to admit is actually good for us – like visiting the dentist.  What do I need to say and how can I do this without waffle or jargon?  There’s really no better way to discover whether you understand your subject; that and a couple of dozen random questions.  It’s a process that we regularly go through when composing the ‘lay abstract’ of a grant application but those words can seem trite when you read them in public.

My challenge was to convey the excitement and relevance of research into brain development, how one fertilised egg becomes billions of nerve cells with trillions of connections.  My talk was titled ‘The Broken Brain: Too complex to mend?’ because I believe that in the rush to fund ‘translational’ research and find cures for nervous system disorders, the role of developmental biology in understanding how the brain gets wired up is crucially overlooked.

It’s nice to have a safety blanket and mine took the form of a model brain I would normally use for teaching anatomy.  It was familiar, it gave the audience a tangible idea of what I was talking about, it made me look like I was in a neuroscientists’ production of Hamlet.  Most importantly, holding it stopped the excessive hand waving to which I am prone, especially when nervous.

To illustrate the many brain pathways involved in performing a simple action, I tried a new way to get the audience involved.  Roughly mapping positions the audience were sat in with a map of the brain, I joined up people sitting in the ‘visual cortex’ to the ‘thalamus’ to the ‘motor cortex’ back to the thalamus and so on…until it ended up with me surrounded by a tangle of wool which hopefully did a good job of showing the many areas that need to be connected for the action they had chosen (skipping).  This is not the sort of thing I would normally contemplate doing but having had the usual crutch of Powerpoint removed there remained little point in dealing in half measures; it was interactivity or bust.  And in the end it seemed to pay off, the audience joined in with good humour and the resulting tangle certainly proved my point about the brain’s complexity.

So where did the Marmite (other yeast-based spreads are available) come in?  A large jar of it became a prop to clutch instead of the model brain.  Embryonic nerves are guided to their targets by environmental cues that can be either attractive or repulsive.  Like sandwich fillings, the same signal can be one or the other depending on the individual nerve cell that tastes it.  Understanding these responses is at the heart of my research and potentially underlies future therapies to promote and direct nervous system repair.

The talk contained elements I had never tried before but at least it was entirely under my control.  An open question and answer session holds no such certainties and naturally people’s questions about the brain were far more wide ranging: what is the effect of alcohol or cannabis?  Are video games harmful?  What causes consciousness?  Can we turn the brain off and on again?  (My fault for wearing an IT Crowd t-shirt).  Honesty is the best policy.  If I could answer all those questions I would have a Nobel Prize (but hopefully still be writing this blog of course).  People are happy to hear where the limits of knowledge lie – the challenge is to explain where these are and why, in clear language, without patronising.  The problem is usually with the explanation not their comprehension.  The other important point is that good public engagement is a two-way process so these sessions should involve the supposed expert researcher listening to people’s ideas and concerns as much as reeling off clever answers or mind-blowing facts (although a few anecdotes always come in handy).  Having said all that what did I learn from the audience and the evening then?

  • Give the audience the benefit of the doubt.  Questions featured alcohol during pregnancy, cannabis, omega-3 oils, video games, teenage behaviour – all topics that have me instinctively flinching and waiting for some ill-informed rant rehashing tabloid scare stories.  In fact, nothing could be further from the truth.  Despite my misgivings, most people are aware that a balanced diet is better than any faddish superfood, that most things are fine in moderation. They are interested in hearing a balanced appraisal: yes there is evidence that omega-3 can be beneficial for nerve cells but no, we don’t really know for how or when which is why we are studying it.
  • Don’t underestimate the power of social media.  I was asked if I have a YouTube channel with the films we make of nerve cells in my lab.  It had never occurred to me!  (Incidentally this was reinforced a few days later by a talk about public engagement at the Exeter Imaging Network – more about that coming up in another blogpost).  Anyway, I’m now determined to get my homepage in order.
  • If in doubt give it a go.  Even with minutes to go before I spoke, I was still toying with the idea of chickening out with the wool wiring diagram.  I’m glad I didn’t.  It put people at their ease and managed to illustrate an important point at the same time.


They are keen to have a wide range of speakers down in Falmouth so if you are at all interested please let me know ( or tweet @axonology). They have a small budget to help with travel costs and you are liberally fed and watered, although Marmite sandwiches were not on the menu.


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