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Secret Life of Jellyfish

Hello all! My name is Anastasiya and I’m a computer engineering and neuroscience double major at the University of Cincinnati. I’m curious about the world around me and my favorite thing to do is learn. My hobbies include making strange noises, fangirling over the fuel efficiency of my car, and volunteering while spreading knowledge to the general public. I mainly volunteer at the Cincinnati Observatory, home of the oldest professional telescope open to the public, and at Cincinnati Public Schools, where I help out with a Lego League robotics club and mentor a group of high school scholars.

This summer I’m investigating ‘The Secret Life of Jellyfish’, specifically, of the clytia hemisphaerica. They’re super tiny (they max out at about 20mm in diameter) and seem to be capable of doing things they shouldn’t be able to do. By that I mean that these jellyfish seem to exhibit relatively complex behaviors without making use of a brain (since they don’t have one). They’re also kind of ridiculous and paradoxical to me, because trying to lift one out of the water could easily kill the clytia since the surface tension of the water is too much for it to handle, but you can chop it in half and it’ll be just fine as two separate jellies. Weird (but cool)!

The current plan is to record videos of the jellyfish in various situations and then use some form of machine learning to figure out the jellies’ behavior. I’ve looked at some potential tracking software, libraries, and random snippets of code, and it seems that OpenCV is my best bet for analyzing the videos, so I’ve spent the last couple weeks learning about it and how to use it in Visual Studio 2017 with C++. But learning about code is not all I’ve done; I’ve also been preparing for the impending arrival of clytia hemisphaerica to our laboratory.

I first made sure to get a (hopefully) decent environment set up for them. Clytia hemisphaerica need salt water at a salinity of 1.0268, or 37 parts per thousand, and a small current to keep them swimming as this is critical to their health. The housing units I set up are based on the traditional beaker method and include 3.7L beakers (actually 6”x8” glass vases from Amazon) filled with artificial sea water as well as a constant current stimulator made of acrylic rectangles, hot glue, plastic pipettes, 12V 5RPM motors, some wires, and an AC to DC adapter. All of these things together should provide a nice home for the jellies when they arrive, but that is not all I need to prepare.

Jellyfish, like many living things, need a food source, and the one I’m preparing is artemia, otherwise known as brine shrimp. Brine shrimp are pretty easy to hatch, and just one cap-full of brine shrimp eggs makes a very large amount of baby brine shrimp, enough to turn an entire bottle and beaker a shade of orange. That must mean that, after a one-time investment of a large batch of artemia, I am all set on jellyfish food for the summer, right? Well, there’s a catch. The catch here is that clytia hemisphaerica should only eat 1.5 to 4 day old brine shrimp, and eating ones that are are outside this age range for prolonged periods of time could have deadly consequences for the poor jellies (and for my easily over-attached heart). This means I’ll have to constantly hatch and culture new batches of brine shrimp and keep track of hatch dates so I have the proper feed for these picky eaters.

 

At this point, I’m pretty sure everything is ready for the jellies to come in, and they should be gracing us with their presence any day now. I’m very excited to be working on this project as a fellow at Backyard Brains, and I can’t wait to see these jellyfish in person! The more I learn about them, the more mysterious and intriguing clytia hemisphaerica become, and I look forward to finding at least some pieces to the puzzle that is their behavior.


Nothing in life is free…

“You are not controlling the storm, and you are not lost in it. You are the storm.”

-Sam Harris

 

The previous quote originated in a book called Free Will by Sam Harris. I take it to loosely mean that we do not exert conscious control over our thoughts and actions (free will), though we do not live out our lives as mere puppets of fate serving a larger-than-life purpose (determinism). Perhaps we are the sum total of our thoughts and actions, which themselves are traces of information propagating through a complex network of biological structures that has adapted to all it has ever mediated. Demonstrating the ubiquity of the signal traces which accompany our actions can act as the first evidence that it is the nature of humans to meander stochastically through space and time and to perceive our own “free will” so as to feel a little bit better about ourselves.

Now where would one look for free will? It is my belief that the first place to look is the final stage in motor control for the brain: the Primary Motor Cortex. Attaching an electrode vaguely over the region of the motor cortex associated with arm movements, and subsequently initiating arm movements being recorded via electromyography (EMG), or electrical muscle recordings, offers a simplified paradigm for scoping out a “readiness potential.” This characteristic waveform is an artifact of movement initiation, and it is possible that once the onset of the readiness potential can be accurately detected, a machine learning algorithm could be used to classify the signal and subsequently alert a subject of their intention to make a movement prior to onset. My first step was to locate the readiness potential, and I believe that I have done so. My next step is to test a wide variety of classification systems, filters, and novel computational methods for predicting arm movements.

The above figure shows the average EEG signal across multiple trials aligned by the recorded onset of movement via EMG. Movement initiation is shown by a vertical bar at 0 seconds. The monte carlo test window of 95% confidence is shown in red. The EMG was recorded from the right wrist flexor with the ground wire connected to the medial epicondyle. The EEG was recorded from C3 on the left side of the head with the reference electrode placed below the base of the occiput and the ground placed on the left mastoid, behind the ear.

My name is Aaron and I like to hear myself talk too much. I have one more year of schooling until I obtain my BS in Bioengineering from the University of Pittsburgh. In my spare time, I’ll pretty much do anything as long as it’s fun and/or challenging and/or competitive. Such activities may include, but are not limited to: frisbee, soccer, piano, baseball, board/card games, Rocket League (ranked Diamond in Standard and Doubles), and eating a lot. Also, I enjoy a good conversation.

This is a picture of me (left), my siblings (all older), and my niece.

 

My project is actually a continuation of previous Fellow’s project back in 2016. I’m going to be expanding on Patrick’s work, so make sure to check out his blog posts for some background information!


Rock ‘Em Sock ‘Em…Shrimps?!

Hi folks! My name is Dan and I am a student at the University of Massachusetts Amherst studying neuroscience and minoring in computer science. Back at school, I work in a songbird lab where I listen to neurons fire in zebra finches, and I’m on the ballroom dance team. Outside of working, sleeping, and eating, I’ve been rock climbing with the other Fellows and scouting out dance spots around town.

 

So at this point in 2018, I’m guessing a bunch of the people who will read this have at least heard about the focus of my project, mantis shrimps! Radiolab did a fabulous show about them and since then they’ve spread across the internet, so I was pretty darn excited when I found out I’d get to work with them this summer.

 

Mantis shrimp

Even though there are a million great resources on mantis shrimp, I’m going to take a shot at it here anyway. They’re prolific like ants and old like crocodiles; they comprise a few hundred species of related crustaceans can be found across the world’s temperate oceans, and they haven’t changed much for thousands of years. One species can be found along the Atlantic coast from Maine to Suriname! They range in size from less than an inch to more than a foot long, and several species are vibrantly rainbow colored. Despite their pleasant color, they are extremely aggressive and will attack just about anything. There are a ton of things about mantis shrimp that make them biologically unique and really important to study, but I’m going to talk about just one aspect of their behavior/physiology: their punch.

Most species of mantis shrimp are considered “spearers” or “smashers,” because they use an arm-like appendage called a maxilliped to either spear or smash their prey. I’m studying a smashing species called Odontodactylus scyllarus, or the peacock mantis shrimp. In addition to looking like a Christmas ornament, they pack a punch like no other animal, or even robot, on Earth. Their maxillipeds have an enlarged blunt “elbow” that they swing faster than a bullet (underwater no less! Try swinging a baseball bat underwater some time). The impact of their punch pushes all the water away from the point of impact, replacing it with gas the temperature of the surface of the sun, creating what’s called a cavitation bubble. The water then crashes back down around the bubble, creating an audible click, a flash of light, and an aftershock that hits the target like another punch. This is one reason scientists are curious about these guys: we can’t engineer something as hydrodynamic as their little rock’em sock’em maxillipeds. By the way, this kind of spring-loading is called power amplification.

How does the mantis shrimp still outpace modern engineering? I think I’ll get really into it in my next post, but the basic idea is that they store mechanical energy into a kind of biological spring on their armor, twitching muscles in the maxilliped. Each twitch pushes the spring further and further down until it releases a latch, and that elbow catapults out into a very unlucky crab, scientist’s finger, or aquarium glass (they have been known to crack and break).

 

My project

Our bodies produce a lot of electricity to do everyday things. The brain uses electricity to propagate information from one neuron to another, and we use electroencephalography, or EEG, to see how electricity use changes when we perform cognitive tasks. Electromyography, or EMG, is a way of visualizing the electrical activity of muscles. What I want to do for my project is capture the mantis shrimp EMG  (“electro” = electricity, “myo” = muscle, “graphy” = visualization) that reflects the buildup of mechanical energy before its strike, and then take a slow-motion of the strike. Maybe I’ll be able to see some cavitation! The EMG trace for mantis shrimp strikes is quite well studied. A fantastic paper on strike EMGs from 2015 (see below) shows a distinctive pattern of activation in the muscles. I’ll be looking for a similar kind of trace when I do my work.

Power-amplifying EMG trace from a mantis shrimp leading up to a strike

Before I can get started on that, I have to practice getting EMGs from other organisms that use power amplifications — specifically, crickets and grasshoppers. And cockroaches for the extra ew-factor. That’s what I have been doing for the past week: cobbling together a surgery rig, anesthetizing insects in ice, and implanting EMG probes. And it’s worked!

Cockroach EMG data I acquired the old-fashioned way: with an oscilloscope.

 

Further information on the mantis shrimp:

Radiolab

The Oatmeal