Thinking about Sponge

In the split second between “I’m hungry” and “Ooh, a nice salad” millions of fizzling brain cells, or neurons, meet at junctions called synapses to communicate our desires (cake), our awareness (already had cake) and our memories (what’s in the fridge?). Of course, our synapses are involved in many different types of activity, but feeding might be where it all began. In this freshwater sponge (Spongilla lacustris) – pictured using electron microscopy – scientists find synapse-like structures, even though this primitive animal doesn’t have a nervous system. Zooming inside one of its feeding chambers, we see neuron-like ‘neuroid’ cells (highlighted in purple) reaching out, using chemicals to communicate with digestive cells called choanocytes (blue, green and yellow). While researchers spot similarities with human neurons squirting neurotransmitters into synapses – and making use of similar genes – it’s perhaps not surprising that the first thoughts evolved from where the next meal is coming from.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

Website

• Video by Jacob Musser, Giulia Mizzon, Constantin Pape & Nicole Schieber / EMBL
• Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
• Video originally published with Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
• Research published in Science, November 2021