The "How Your Brain Works" book cover on the left with authors Tim Marzullo on the top right and Greg Gage on the bottom right.

How Your Brain Works makes neuroscience available to everyone. Authors Tim Marzullo (top) and Greg Gage offer humor alongside science via illustrative drawings. Artwork by Cristina Mezuk.

Have you ever wondered how sleep can improve memory? Or considered how your eyes perceive color? It turns out that you do not have to be a degreed scientist or even work in a lab to find out! 

These questions all pertain to neuroscience, and it is possible to research them yourself by conducting the experiments in neuroscientists Greg Gage and Tim Marzullo’s new book, How Your Brain Works. Gage and Marzullo, the founders of Backyard Brains in Ann Arbor, make neuroscience available to everyone via more than 45 at-home tests outlined in their manual. The chapters keep the reader on the edge of their seat with the questions that the authors ask and the methods through which they answer them. As the two neuroscientists write, “Scientific discoveries can happen anywhere.” Plus, it is not only science – Gage and Marzullo offer humor alongside the science via illustrative drawings.

Neuroscience has long been an expensive endeavor, but tools that appeared in the early 2000s changed the landscape and brought neuroscience out of institutions and into anyone’s hands, Gage and Marzullo write. The premise of How Your Brain Works hinges on these technologies: 

This book allows you to learn about neuroscience research and actively participate in the field. We aim to provide access to tools and techniques so that you can develop a sense for what questions to ask using neuroscience experiments and what the limits are of current technology. What was previously only found in labs at advanced research universities is now available for anyone with curiosity. The walls have disappeared, the locks are gone, the bars have been lifted, and the drawbridge has lowered. Neuroscience and self-knowledge of your brain are yours for the taking.

And who might the audience be? Everybody, from students to parents, and curious souls. 

Take meditation, for example. Gage and Marzullo walk readers through setting up an experiment to see the difference between brain waves from a person at rest and brain waves from a person who is meditating. Important factors in the study include randomly changing the order of the meditation and rest so that any changes detected between the two states cannot be attributed to variables related to the sequence of events. In fact, this manual not only provides hands-on practice with neuroscience concepts but also tips on experimental design. Gage and Marzullo reflect on the results of trying to measure meditation versus rest:

This experiment goes to show that often science isn’t hard due to complex formulas and jaw-breaking Latin denominations. It’s hard because you have to ask the right questions and choose the right approach. 

How Your Brain Works illustrates several methods, from attaching electrodes to a subject’s head to running trials on invertebrates, with care taken to avoid harming the creatures. The appendices offer details on how to care for the cockroaches involved in the experiments and how to make or get the SpikerBox, which is the tool for measuring electrical signals in research projects. 

Gage and Marzullo met at the University of Michigan as neuroscience doctoral students. Gage is now a professor at the University of Michigan. Together Gage and Marzullo co-founded Backyard Brains, which produces kits for students at all levels to learn about the brain. We recently spoke to both of them about their partnership, their experiments, and their new book. 

A black-and-white illustration of a brain in the center with the words, "REM," "Stage 1," "Stage 2," and "Stage 3" surrounding it. The illustration also includes brain wave lines in all four corners of it.

Greg Gage and Tim Marzullo examine brain waves from people who are at rest and people who are meditating. Artwork by Cristina Mezuk.

Q: Tell us the story of how the two of you met and started working together while at the University of Michigan.
Tim Marzullo (TM): We both did our Ph.D. work at the Neural Engineering Lab on North Campus, and we became friends while doing experiments together. I was drawn to Greg’s unique sense of humor and his “don’t take yourself so seriously” style, which is not common in science. He also worked in industry before going to graduate school, also uncommon, and I liked hearing his funny stories about corporate culture.
Greg Gage (GG): I met Tim in the Neural Engineering Lab. I remember meeting Tim and instantly hitting it off. I loved his independence and original thinking. I remember a postdoc warning me that working with Tim would be bad for my career because he did things against the mainstream way of thinking in typical grad school. But that was why I liked him.

Q: Would you also share with readers how you developed Backyard Brains?
GG: It was a great time for startups in the fall of the financial markets in 2008. Tim and I entered a pitch competition called Dare to Dream through the business school on the idea of the SpikerBox. We lost to a group of young students but decided we would continue to pursue the idea. We eventually won a pitch competition and got to go to California to pitch the ideas to venture capitalists in Silicon Valley. But we were not the typical software startup with exponential growth and we were told “Good luck.” That winter we registered as a company, and the rest is history. 
TM: Both of us are the first scientists in our families, and we did a lot of local outreach together. We realized that the tools for teaching neuroscience at the high school level were lacking in sophistication. We thus had the idea to develop education-grade neurophysiology kits. We were also inspired by the computer revolution and wanted to do the same for neuroscience.

Q: The book describes the possible audiences for How Your Brain Works. Who do you picture benefitting from this book? Have there been any surprising audiences who have taken up this book that you did not expect? 
GG: The benefits go both ways with our audience, meaning the book is designed to get kids thinking about neuroscience, but they often get us thinking, too. We had many occasions where students’ questions would lead us to develop new experiments or technology. The iOS app was an example. A group of high school kids did experiments that led us to introduce new stimulation techniques. 
TM: We have found professional scientists often buy the book for their young kids, as it goes through the “nuts and bolts” of neuroscience in a fun way, talking about actual experiments and not just the history of neuroscience (though we also do that).

A black-and-white illustration of a beaker with the words, "Curiosity, Creativity and Action" written on it.

How Your Brain Works highlights the fundamentals of neuroscience through examples, experiments, and history. Artwork by Cristina Mezuk.

Q: Black-and-white drawings clearly and entertainingly illustrate the experiments and concepts in the book and make the ideas more approachable. How did you and your illustrators develop this style? How do you see the drawings enhancing the chapters? 
GG: The first drawings were done by our grad school friend, Cristina Mezuk. She was an artist but didn’t work in publishing. So she would draw for us on her nights and weekends. We liked the simplicity of her style and the way we could mix humor into a rather serious subject. Over the years we found other artists that used a similar style to capture attention and explain complex concepts. 
TM: We have spent a lot of time thinking about public communication, and we discovered that custom artwork draws people in. We are also fans of drawing and indie-comic books (a lot of which we read at the AADL or the Vault of Midnight), and thus we found a local artist when we started documenting our experiments on our website. 

Q: Were the studies ones that you had done already, or did you develop them specifically for this book? How did you agree on which topics and projects to include or exclude? 
GG: This book draws on the experiments we developed over a decade of our R&D and from running summer programs for students to developing lesson plans. There were some developed specifically for the book to make certain sections feel complete, for example, the bee vision experiment. 
TM: We have some novel experiments in our book that we haven’t published before (like movement prediction or your brain on meditation), but the majority of our experiments have been extensively tested in classrooms around the world. Our group has many formal publications (in scientific journals), and some of our experiments, such as the cockroach, cricket, and earthworm experiments, are based on our heavily cited papers.

A split black-and-white illustration of moths with the words "Non-Reproductive Behaviour" on the left and the words "Reproductive Behaviour" on the right.

How Your Brain Works explores the ethical treatment of invertebrates in experiments. Artwork by Cristina Mezuk.

Q: As you mentioned, some of the experiments involve cockroaches, earthworms, silk moths, and honeybees. The book talks extensively about the ethical treatment of animals in research, and the procedures walk readers through humanely anesthetizing the creatures as part of conducting the research. What advice do you have for squeamish readers?    
We spent the most time developing the ethics chapter of the book, asking others for feedback, and trying to be as honest as we could about why we felt what we were doing was in the best interests of humanity, with minimal harm to the invertebrates. I have found that the students that were the most squeamish about the cockroaches at the beginning of lessons, were the ones sticking around and asking questions to learn more, as if the creative way of thinking could be the reason for the initial fear. 
TM: All of our individual neuron experiments deal with invertebrates (insects, worms, etc.), and we tried to design all of our experiments so that the animals can go on living their lives after the experiments. To record from neurons, because the electrical field is very small, you have to put electrodes in living tissue. We know some users would prefer not to work with animals, thus 2/3 of the experiments in our book are non-invasive human experiments on brain/heart/eye/muscle electrical recordings. 

Q: If readers want to learn more about neuroscience after doing the experiments in your book, what do you recommend reading or trying next? 
 We structured the book with a phenomenological approach, meaning we tried to lead with the observations and work backward on how we were thinking about what questions we should ask next. The nice thing about the field of neuroscience is that there’s so much we don’t know. We end chapters with a number of follow-up experiment ideas. I hope that people who read the book try them out, or develop new ones around something they are interested in. 
TM: Our dream is that more of the public is involved in original research, so we recommend reaching out to a local university (or us) to design your own experiments and try to publish them in some form (either a blog or even a formal publication).

Q: With How Your Brain Works published, what is coming up next for you both? 
GG: Many of the experiments we developed relied on programming (neural engineering) and were kept out of this book. I suspect the next book will be something along the lines of “How to Control With Your Brain,” where we look at using software, servos, and stimulation like we do with the claw, human-to-human interface, and the roboroach. 
TM: It took three years to work on the book, and it came out in November of 2022, so we are relaxing on our writing efforts for now. In April a version in Spanish was released called Cómo Funciona Tu Cerebro by Oberon Libros in Spain, and a version in Italian will come out later this year. Our customers and MIT Press have also asked for a book geared toward students under 11 years old, which we are brainstorming. We may also write a book on our neural engineering experiments (our current book deals more with neurobiology).

Martha Stuit is a former reporter and current librarian.