Mapping Neural Networks of Jellyfish-Like Creatures

Rice University  engineers are conducting comprehensive analysis of hydra to learn how they sense touch, a small step toward understanding neural networks in all living creatures. Hydra vulgaris, freshwater creatures that look like miniature jellyfish polyps, expand and contract as they navigate their environments, but can also be prompted to do so by giving them a poke. The Rice lab has developed highly specialized equipment over the last decade to do that, temporarily constraining the animals in the channel of a microfluidic device to capture simultaneous images and data that detail their muscular and neural responses.

Transcript

00:00:00 [Music] we're really excited to work with hydra because it's an animal that's so different from the animals that we typically work with in the lab and they're so different from us and so then you might ask well why are we studying something that's so different from humans what does that mean for me

00:00:18 [Music] what i think is really interesting about working with hydra and its relationship to to humans is that by looking at similarities in the way that hydra's nervous system works and the way that a mouse or human's nervous system works we can understand really deep principles that

00:00:37 are conserved from perhaps the very first nervous systems in nature and that is really i think the fundamental building blocks upon which all nervous systems are built including our own so we want to kind of understand how this animal responds to mechanical touch and these things are really tiny we need to make something small enough

00:00:58 so we could stimulate a very specific part of the animal and not the whole animal at once we could understand how it responds to this this light touch the lead author on this christian body wallow went to the clean room and she built these microfluidic devices that have a bunch of valves you can see here there

00:01:17 are nine valves in a chamber that could house one of these animals in this case we're going to show you one valve see what it turns on right there that's when we're applying a stimulus and so you can see in in this image here this animal has a protein in all of the neurons so essentially we can watch the

00:01:38 activity in all the neurons and when those neurons are active that neuron will get brighter and what we'll look for is we'll look for when we touch the animal what does that nervous system do how does it encode that sense of touch and what i think is interesting about this is that you'll see there's not a

00:01:56 lot of structure right these neurons are kind of everywhere but maybe there are specific groups of neurons that are responsible for driving this animal's behavior you see right there there's a valve and you actually see a bright ring of neurons at the bottom we'll do the same thing with the muscle

00:02:13 cells and you'll see right when the valve hits these muscles respond that shows me the animal is contracting and see each time that we apply a stimulus we get that same kind of pattern of activity in the in the neurons and in the muscle cells what it allows us to do is go back and look at these pictures

00:02:30 where it looks like there's not a lot of structure that this nervous system might be kind of random and it doesn't have the centralization that we see in animals like rats and mice and humans but what we discovered is that despite what looks like a distributed network there are groups of cells that form these

00:02:49 structures that are responsible for computing things like response to touch and computing things like controlling the animal's movements [Music] these animals can self-renew their entire nervous system they can live forever because they're they're regrowing every neuron in their

00:03:07 body every 20 days you can cut their head off they regrow a new head you can cut their foot off they go underfoot so these remarkable regenerative abilities if we could understand them we might be able to learn how we might be able to improve our own treatment of humans and how they might recover from injuries like traumatic brain disorder

00:03:23 or stroke you