Let’s say you’re a zombie. You’re lumbering around, doing your zombie-mumble, and just ten feet ahead you see a living human being. Your first impulse, of course, is to head over there and eat their brain. And you’re about to do just that, when suddenly you feel a pang of something like shame.
You remember, dimly, being a human yourself. You remember how you might’ve felt, if an undead weirdo got to gnawing on your skull. You’re at an impasse: at once desperate for brain meat and reluctant to kill for it. So you head to your zombie psychologist and start explaining the situation, and your zombie psychologist starts grinning, which annoys you at first — I mean, you’re baring your soul to this guy — until he explains what’s on his mind.
Turns out, he’s been toying with an idea — a pilot program for conscience-stricken zombies. Instead of human brains, they’ll be fed stuff that looks and tastes just like brains, thereby sparing them the obligation to kill. The only thing they need to work out is: what would be an acceptable substitute for human brains? For this week’s Giz Asks, we reached out to a number of brain experts to find out.
Associate Professor, Neurobiology, Harvard Medical School
The brain is of course composed primarily of lipids, and so it is perfectly reasonable to assume that it is brain lipids that zombies really crave. But why human brains and not, say, mouse brains? Lipidomic analysis reveals that human brains are unusually enriched in a compound called sphingomyelin (relative to brains from rodents), and so it is further reasonable to assume that what zombies want is actually lots of sphingomyelin. So where to get it? Eggs. Eggs are packed with sphingomyelin. Furthermore, eggs also have the advantage of having a white outer cortex and a lipid-rich centre, just like the human brain, so they seem a reasonable substitute all around.
Chair and Professor of Neurology at the David Geffen School of Medicine at UCLA and Co-Director UCLA Broad Stem Cell Centre
A food-based substitute would require a fair amount of work, because you’d have to get a sort of fatty, proteinaceous slop together as a mimic for the brain. A thick macaroni and cheese might work, with a larger noodle like ziti or rigatoni — and no tang, meaning a thick white cheese, as opposed to cheddar.
The “brain sandwich,” made from cow brains, was an unusual delicacy in St. Louis for years. When I lived there, I saw what it looked like as they fried it, and it’s hard to imagine any other organ meat could substitute for the real thing. Kidney and liver are too firm and too structured; most foods we eat, or could think about eating, are also too firm, and not fatty enough.
A brain from another animal might work, though it would have to be an animal with an advanced brain — that is, one with the folds we see when we look at the brain’s surface (which are called gyri and cilici). Those are what distinguish higher mammals from lower mammals. They also make the human brain this particularly characteristic thing in terms of substance and texture and appearance. So an animal brain, to sub for a human brain, would need to have those features. That would mean anything from, say, a dog or cat on up — those both have gyri and cilici, whereas rodents and rabbits, for example, do not.
Assistant Professor of Brain Science, Psychiatry and Human Behaviour at Brown University
I think my Zombie would be a vegan. The thing that I have found to be the closest in texture to the brain is tofu (not the firm kind). People are often surprised by that fact, because it’s really soft — you can put your finger through it easily.
Broadly, I study the kind of complex planning and decision making that is localised to the front of the brain, the prefrontal cortex. This area is also one of the most likely to be injured if you hit your head, because your very soft brain bounces around inside your skull. Our lab typically does a demo for Brain Week and other events that lets people feel tofu, and then shake it around in a container and see what happens to it. Shake it around in some water (mimicking some of the protections that our brain has in the cerebro-spinal fluid that it floats in) and the tofu does much better (which is why it’s packaged in water!).
Unfortunately tofu doesn’t mimic all the wonderful folding that it has that lets us pack so many brain cells into a tight space. A sheet of paper crumpled up is best to show that capacity, but paper is probably much less tasty than tofu (to humans anyway, I don’t know about zombies!).
Professor, Systems Biology, George Mason University
My proposal is: a literal pound of flesh. Many people have too much of it; it’s very similar to the brain in texture; it has a lot of cholesterol, which is important, because — in my opinion at least — zombies would crave exactly that. Also, adipose tissue is very rich with various kinds of growth hormones and other kinds of bioactive stuff. If you could develop some kind of device that would transfer the flesh to the zombies, people might even be grateful — they wouldn’t have to get liposuction.
Senior Lecturer, Medical Biotechnology, Deakin University
The best thing to do would be to make small versions of a brain from stem cells, called organoids. These are almost, but not quite, brains. You grow them in an artificial 3D environment that mimics the properties of the central nervous tissue, and allow them to develop networks of neural cells in a structured way. They’re used for research into drugs and diseases and so on, but would probably be an acceptable meat-free snack for an ethically conscious zombie plague.
Professor in Neurology and Professor of Biomedical Engineering at Duke University
If I were a vegetarian zombie, I would try to make a brain substitute using the major components of the brain — carbohydrates, proteins, and cells. The major carbohydrate component is hyaluronic acid (which is found in many beauty products, and can be purchased in bulk). Though by itself it does not form a solid, only a very viscous liquid, it can be combined with other materials that do form a solid. For example, sea weed has a carbohydrate named alginate that does form gels when combined with calcium. So, a blend of hyaluronic acid and alginate with calcium can yield a material that has the mechanics of the brain. For the protein component, eggs, beans, soy, and quinoa all can be good choices. To get the texture right, the calcium can be added while stirring to generate chunks. If it is OK to eat other animals, then I would buy pig brains, which are often discarded. Pig organs are close to the same size of humans and have even been used for transplantation due to similarities in physiology/biochemistry. That would be the simplest choice.
Associate Professor, Psychology and Neuroscience, George Mason University
Whenever I eat cauliflower, I think of the cerebellum or “little brain.” It is tucked away behind the cerebrum, or main part of the brain. The cerebellum is small, but it is where about 80 per cent of the entire brain’s neurons are found! Most of the cerebellum’s neurons, or grey matter, are found on its outer surface. They are tightly packed together in little folds called folia. The neurons in the folia are connected to each other by nerve fibres, also known as white matter. When the cerebellum is cut in half, the white matter appears as this beautiful network of branches called the arbor vitae, or tree of life. It really does look just like a head of cauliflower!
Professor, Psychology and Neuroscience, Trinity College
The brain is actually quite soft and squishy. Fortunately for us it normally floats in a pool of cerebrospinal fluid that serves as a cushiony packing material protecting the delicate brain from the hard skull. But the brain is so soft it can easily become injured without the head striking any object. If there is enough rotational or acceleration/deceleration motion for the brain to hit the skull the tips of the brain can be bruised and individual cells can be stretched or sheared from their connections. This can happen, for example, in motor vehicle accidents or shaken baby syndrome where the head is thrown very quickly forwards and then backwards.
The consistency I think the brain comes closest to is a gelatin. But I would recommend that our zombie make the gelatin with milk rather than water. This will give it a closer consistency to a brain, the colour will be more opaque like a real brain, and it will provide more of the much needed protein the zombie craves. There are even commercially made gelatin molds if the zombie is able to access stores or online shopping.
Another option would be a soft tofu. This might be a great option for a zombie who is a vegetarian or vegan. There is plenty of protein but it will be much harder to mould into the right shape. Sadly, most zombies are not portrayed to have the fine motor skills needed to create a brain shape from scratch, so the tofu would just have to be eaten as is.
On a side note, if our zombie truly finds that nothing satisfies like a real brain, they could certainly consider becoming a neurosurgeon that specialises in therapeutic surgeries, like temporal lobe resections. In this case, a small portion of the temporal lobe of the brain is removed to relieve a person of intractable epilepsy. This might allow for a chance to satisfy their craving while providing benefit to the person involved.