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Ask Dr. Universe Neuroscience
University Communications Network > Ask Dr. Universe > Academic Subjects > Biology > Neuroscience

What is the human brain made out of? – Trevor, 9, Illinois

Dear Trevor,

Everything we do and think is thanks to the 3-pound organ tucked into our skulls. But what is it made of?

I asked my friend Samantha Gizerian. She’s a brain scientist at Washington State University.

She told me the brain is surprisingly soft and mushy.

“We think about our other organs and tissues, and they’re squishy in a very solid way,” Gizerian said. “Like when you go to the grocery store and get a carton of meat. You can squish on the steak, right? Our other organs are mostly like that as well. But the brain is very, very delicate.”

She told me it’s more like the ground up burger people use to make meatballs. Or like soft tofu or a Jello square.

The brain is extra soft because it’s about 60% fat.

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How do fish hear? — Lamarcus, 8, Ohio

Dear Lamarcus,

My goldfish roommate hates when people tap on his tank. The tapping sound he hears in the water is loud and scary.

I talked with my friend Rikeem Sholes about how fish hear. He’s a fish scientist. He studies salmon hearing at Washington State University.

He told me that a fish’s hearing system includes sensory cells in the inner ear and in a line along the outside of the fish’s body and head. Some fish also use their swim bladder to have super hearing.

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How long do you have to train to become a scientist? – Katelyn, Texas

Dear Katelyn,

Maybe you dream of pointing your telescope toward distant galaxies. Or zooming in on microscopic life on Earth. Being a scientist is an amazing job. You can also do science for fun—no matter your age or anything else about you. It belongs to everyone.

I talked about science training with my friend Kalli Stephens. She’s earning her bachelor’s degree in genetics and cell biology from Washington State University. WSU has a strong undergraduate research program. So, Stephens has been working as a scientist while going to school.

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How does the brain transfer signals to each body part to move? Yulissa, 11, Virginia

Dear Yulissa,

Your brain weighs less than 3 pounds but has the power to move your whole body. That’s because it’s part of your nervous system.

Your brain and the spinal cord that runs down your back make up your central nervous system. You also have a peripheral nervous system made up of nerve cells. These connect your brain and spinal cord to all the other parts of your body.

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Dr. Universe: Why are brains mushy? – First Graders, Waller Road Elementary, Puyallup, Wash.

Dear First Graders,

You’re right, brains are quite mushy. It turns out the three-pound organ between your ears is mostly made up of water and fat.

I found out all about brains from my friend Jim Peters, a neuroscientist at Washington State University.

“It’s gooey. It really is squishy,” he said. “When it is warm, it is kind of like butter.”

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Dear Dr. Universe: How do we talk? – Emmy, 7, Wash. State

Dear Emmy, When you were a little kid, maybe you played Peek-a-Boo or sang “Itsy Bitsy Spider.” These kinds of games and songs have a lot of the different sounds we make when we are first developing speech. A lot of humans start out playing with speech through cooing and crying. At about six months old, this cooing and crying turns to babbling. A baby might make sounds such as ma-ma, pa-pa, or ba-ba. Read More ...