Name: A Memorable Snail
Uploaded: undefined
Duration: undefined

NOVA ScienceNOW

The National Science Foundation

NOVA Science Trust Logo

the Alfred P. Sloan Foundation

<div class="rich-text">
	With its extraordinarily large neurons, the marine snail Aplysia has long been a favorite subject for scientists studying the brain and how memory works. In this short video, David Glanzman, a neurobiologist at UCLA, shows what this spineless creature can teach us about our own brains and how we form both short- and long-term memories.
</div>

What can a spineless sea snail teach us about our brains and how memory works?

<div class="rich-text">What can a spineless sea snail teach us about our brains and how memory works?</div>

Video Short: A Memorable Snail

A Memorable Snail

Body & Brain

<div class="rich-text"><h3>
 A Memorable Snail
</h3>

 Posted: June 1, 2009



 NARRATOR:
 
 This sea snail, called
 
 Aplysia
 
 , is somewhat of a celebrity—at least in the world of memory research. It was this lowly snail that revolutionized the way neurobiologists, like David Glazman, think of memory. But how do you give a snail a memory?



 DAVID GLANZMAN (UCLA)
 
 : We are going to give it a few shocks, but don't worry, it's not going to harm the animal, it's not going to produce any long-term damage.



 CHAD COHEN:
 
 Wow



 NARRATOR:
 
 Giving it electrical shocks teaches the
 
 Aplysia
 
 is that the world is a dangerous place. How do we know it has actually learned?



 DAVID GLANZMAN:
 
 We look at a reflex.



 NARRATOR:
 
 Touch the siphon of an
 
 Aplysia
 
 and it triggers a defensive withdrawal reflex--



 DAVID GLANZMAN:
 
 I'm just going to touch the siphon like that. And there you see, that's the reflex.



 NARRATOR:
 
 This reflex can tell scientists if the snail has formed the memory--



 DAVID GLANZMAN:
 
 The longer the gill and siphon remain retracted, that's an indication that it's learned what we taught it.



 NARRATOR:
 
 An
 
 Aplysia
 
 that hasn't been given any shocks will respond with a short-lived contraction.



 DAVID GLANZMAN:
 
 And there it's out.



 CHAD COHEN:
 
 So what was that?



 DAVID GLANZMAN:
 
 11 seconds



 CHAD COHEN:
 
 Alright



 NARRATOR:
 
 An
 
 Aplysia
 
 that was taught to be on guard responds much differently.



 DAVID GLANZMAN:
 
 Now there's the reflex. Now the point is that it stays tucked.



 CHAD COHEN:
 
 So this guy is on a high state of alert here.



 DAVID GLANZMAN:
 
 So you can see the siphon is just starting to come out now. And at 45 seconds, so it is 4 times as long as the naí¯ve animal. And it has learned that there is a danger in its environment, that's what it has learned.



 NARRATOR:
 
 This learning is observed in its changed behavior, but scientists can also see signs of memory in
 
 Aplysia
 
 's legendary brain. Let's just say, this sea snail is "neurologically well-endowed"



 DAVID GLANZMAN:
 
 It has very large, huge, some of the biggest neurons in the world



 NARRATOR:
 
 It's few but gigantic neurons inspired researchers to essentially create an
 
 Aplysia
 
 "mini-brain" out of a sensory neuron and a motor neuron.



 DAVID GLANZMAN:
 
 We take those out of the animal and we put them into cell culture. And they grow together. And then we have a mini circuit, a neural circuit.



 NARRATOR:
 
 Scientists can see, on a cellular level, what happens as the mini-brain forms a memory. So what is happening?



 DAVID GLANZMAN:
 
 Basically, we see two things. The synapse between the sensory neuron and the motor neuron gets stronger.



 NARRATOR:
 
 When the snail gets zapped with electricity, the neurons start communicating differently, sending more, stronger chemical signals and receiving more signals. This change, which can happen quite quickly but does not last forever, corresponds to short-term memory.

But administer the shocks over a longer period of time and the two neurons physically change as the snail learns.


 DAVID GLANZMAN:
 
 Anatomically, we actually see the growth of new synaptic connections between the sensory and the motor neuron.



 NARRATOR:
 
 And it's the physical change in the neurons that is long-term memory. As the snail learns overtime, its brain is making more and more connections, so that even when the snail gets a break from the shocks, it will still remember them.



 NARRATOR:
 
 Besides training sea snails to be on a high state of alert, the research on
 
 Aplysia
 
 has been integral in understanding learning and memory. And not just for snailsâ¦



 DAVID GLANZMAN:
 
 When you're looking at these changes in
 
 Aplysia
 
 , you're basically looking at the bedrock of learning and those same processes take place in our brains.



 NARRATOR:
 
 And with the advancements in memory research that
 
 Aplysia
 
 has already inspired, it is most likely going to remain in the spotlight for decades to come.

</div>

Canada

United States

Northern Mariana Islands

Puerto Rico

American Samoa

Guam

U.S. Virgin Islands

U.S. Minor Outlying Islands

US, US Territories, Canada

US & Territories

NOVA investigates the story of cannabis from the criminalization that has disproportionately harmed communities of color to the latest medical understanding of the plant. What risks does cannabis pose to the developing brain? How much do we know about its potential medical benefits? As cannabis becomes socially accepted, scientists are exploring its long-term health consequences. (Premiered September 29, 2021)Check out a previously recorded panel discussion and audience Q&amp;A featuring experts and producers from "The Cannabis Question" <a href="https://youtu.be/nSTT5RZ_hxA">here</a>.

As state-legalized cannabis spreads, NOVA explores its little-known risks and benefits.

The Cannabis Question

A 2006 composite image from NASA's Hubble Space Telescope and Spitzer Telescope shows the chaos of baby stars in the Orion nebula some 1,500 light-years away. Image Credit: NASA/JPL-Caltech/STScI

With the upcoming launch of the James Webb Space Telescope, the Hubble era is gradually drawing to a close. Here are some highlights from the countless wonders Hubble has shown us during its 31 years in space.

10 spectacular Hubble Space Telescope images

A statue of Zheng He at the Sam Poo Kong Temple in Java, Indonesia. Image Credit: Budianto Santosa, Shutterstock

In the 1400s, Zheng He sailed thousands of miles around Asia and Africa in ships the size of soccer fields, spreading Chinese innovations like compasses and gunpowder in the process.

Transcript

Credits

Support Provided By