Why do you want to be a scientist? Is it hard?

Because it's fun! You get to do experiments all day long, work with your friends, and make up your own projects. Every day there's something new going on. You get to do lots of different things all the time, like running experiments, analyzing data, and going to conferences, instead of just sitting behind a desk all day. Being a scientist can be hard sometimes, because you have to really think about everything you do. But that's also part of why it's fun. Every day there's a puzzle to try to solve - how something works, why something happens, or trying to predict what's going to happen next. There are a lot of discoveries out there waiting to be discovered!

Why are people kept awake during brain surgery?

It might seem like being awake during brain surgery would be really painful. But it's not. The doctors numb the person's scalp and skull. And the brain itself can't feel anything!

People are kept awake during brain surgery so that the doctors can figure out what different parts of the brain do in order to avoid damaging a really important part. For example, say a patient had a brain tumor and he was having surgery to get it removed. The doctors would want to be extremely careful not to damage a part of the brain that was responsible for language, because then the patient might not be able to talk or understand what other people were saying. The doctors would know about where the language area of the brain was located, because everyone's brain is organized in basically the same way. But if the tumor was very close to the language area, they would have to find the exact boundary. They couldn't just use a textbook, because there's a tiny bit of variation between individual people in how different brain areas are laid out. They'd have to find the patient's own personal language area boundary. Here is a picture of about where each person's language area is located.















One way to do this is to have the patient talk to the doctors while they probe his brain in different areas. If probing in one spot causes the patient to stop talking, or to speak incoherently, then that area is essential to language. One way the doctors could probe different areas would be to apply a small amount of electricity to each area. Being awake during brain surgery is probably scary... but it's the best thing to make sure no really important areas are damaged.

How are different animal's brains different?

Different animals need to be able to do different things. If an animal is really good at one thing, then the part of its brain that controls that thing tends to be bigger. For example, dogs have a really good sense of smell. So more of their brain is devoted to sensing and identifying odors. Dolphins have a really good sense of hearing. More of their brain is devoted to listening to and understanding sounds. Birds have very precise vision. So some areas that are involved with vision are bigger in birds. Brains of closely related species look more similar. For example, humans are closely related to gorillas (both are primates). Also, different animals' brains take on different shapes partly depending on the shape of their head! Here are some brains from different animals.

















Another thing that is different between different animals' brains is how many wrinkles and folds they have. This happens because the sheet of tissue that forms the outer part of the brain, the cortex, is bigger in some animals. In order to pack all that cortex into the skull, it wrinkles and folds up as it grows! It's similar to how you can crinkle up a piece of paper in order to make it nice and small to fit in the trash can.

What part of the human brain is bigger? Well, many different parts of the human brain are relatively large. Humans are good at many different things. One thing that humans are really good at is thinking, reasoning, and planning. The part of the brain that controls these skills is called the prefrontal lobe. Humans' prefrontal lobes are bigger than other animals'.

What color is your brain?

Your brain color doesn't have anything to do with your skin color. Everyone's brain looks almost exactly alike - we all look the same on the inside. When it's in your body, your brain has LOTS of blood flowing through it. So it's pink.

If a brain is preserved outside of the body, the outside is a sort of pale brownish grayish peach color, like this:














There are some parts of the brain that are different colors. Many of the wires, or axons, that connect brain cells are white because they have insulation on them called myelin. The insulation helps electricity travel along the axon and keeps it from zapping other axons, just like insulation on a wire in your house. So, the parts of the brain that are made mostly of axons are white. These areas are called "white matter." Here is a cross-section of the brain where you can see some white matter.















There is also a small part of the inside of the brain called the locus coeruleus which is bluish, and another small part on the inside called the substantia nigra which is dark brown. Pretty cool huh?

How do you learn?

Finally, a question where neuroscientists have found a pretty good answer! Learning happens when your brain strengthens the connections between specific cells. Here's one way this can happen.

Brain cells, or neurons, pass messages along to each other. Each neuron has receiving parts, called dendrites, and sending parts, called axons. A neuron sends a message down its axon, which passes the message on to the next neuron's dendrites. That neuron then sends the message down its axon along to the next neuron's dendrites. It's kind of like a game of telephone. Here is a picture of a neuron. All the lines that look like tree branches at the top are the dendrites, and the long line at the bottom that looks like the tree trunk is the axon.

















The point where one neuron's dendrite reaches the next cell's axon is called a synapse. Communication happens when the first neuron's dendrite releases chemicals, called neurotransmitters, onto the second neuron's axon. Synapses are what change when you learn.

There are many ways that synapses can change. For one thing, you can grow more of them. Also, the axon can get more sensitive to the dendrite's neurotransmitters, or more neurotransmitters can be released... kind of like turning up the volume. More dendrites can also grow, which means more space for synapses to form. Especially when your brain is developing, axons can move around in your brain to find dendrites to form synapses with.

So how can you learn better? One way is to go over the same information more than once. Synapses are more likely to get stronger if they get stimulated repeatedly. Another way is to try to learn the information in the way that is best for you. Some people are better at learning things they read, some are better at learning things they hear, and some are better at learning things they talk about with other people. So for example, if you're a hearing learner, you could have someone read you your textbook, listen really well in class, or even make tapes to study from. And, in order to be the best you can at learning, you should always get plenty of sleep, exercise and play a lot, and eat healthy food.

What makes some people smarter?

Depends on what kind of "smart" you're talking about. There are lots of different kinds of "smartness." Some people are good at remembering things they see or hear, some people are good at being creative in things like drawing or dancing, some are good at understanding how things like cars and electronics work... the list could go on forever. No one knows for sure what makes some people better at some things than other people. So far, there is nothing for certain that is different between the brains of people who have high IQs and the brains of people who have average IQs. Geniuses don't have bigger brains or anything.

But, there are changes that happen in your brain when you are really good at something. For example, cab drivers in a big city have to know how to get around on a lot of complicated streets. They pretty much have to have a map in their minds of the entire city. It turns out that one part of the brain that helps you navigate, the hippocampus, is bigger in cab drivers! And, expert musicians have a larger area of their brain devoted to moving their fingers. But both of these things happen as a result of learning. So, the lesson is, anyone can be smart. Your brain changes to help you learn whatever information or skill you want to be smart at!

Why does your funny bone hurt when you hit it?

Man, hitting your funny bone can really hurt. That's because your funny bone is not really a bone - it's a nerve! Specifically, it's called the ulnar nerve and it runs all the way down to your hand. That's why sometimes your hand tingles when you hit your elbow.

Nerves are the wires that connect different parts of the body to the brain. Each nerve is actually a bundle of many tiny wires, called axons. The axons in a nerve either bring information from the body to a brain cell or send information from a brain cell to the body. So when you bang your elbow, your brain gets a really loud message -- OUCH!!

So why is your funny bone called your funny bone if it's really a nerve? Well, a nearby bone to the ulnar nerve is called the humerus. That's the bone in your upper arm. Get it? Humerus... humorous? Pretty funny huh? Here's an x-ray of the humerus.

Why do we sleep?

Another good question! Again, even very smart neuroscientists don't know the answer to this question for sure. But there are lots of theories.

One idea is that you need to sleep in order for your body to repair itself after being active all day. But it has to be more than that, because you wouldn't feel rested after just laying still and not sleeping for eight hours at night.

Another idea is that you need to sleep in order for your brain to do a little housekeeping. Maybe it can't do that while you're awake because it's too busy helping you see, think, move, talk, and do everything else that you do! Some of these housekeeping tasks might include:

• Clearing away any waste made by cells
• Making new molecules that will become building blocks for the neurons or chemical messengers between them
• Helping you solidify new memories and skills
• Giving your brain time to grow

One thing's for sure, though. Your brain and body need sleep. If an animal or a person can't sleep, they can't stay healthy and alert. You actually need sleep to survive! There are several things you can do to get a good night's sleep:

• Try to go to bed at the same time each night
• Get plenty of exercise and playtime, and eat healthy food
• Avoid sugar and caffeine before bed (and scary movies!)
• Do something quiet and relaxing before bed, like reading a book

Where do dreams come from?

From your brain of course! To really answer this question, we have to talk about the stages of sleep. There's more than one kind of sleep! You go through each kind in order several times during the night.

The first stage of sleep is when you're just starting to nod off. The second stage is a little deeper still. The third and fourth stages are really deep sleep. That's when it's really hard to wake up. During each of these stages, your brain becoming less and less active.

After you get through the fourth stage of sleep, there is a totally different, special stage called REM sleep. REM stands for "rapid eye movements." You can tell if someone is in this stage if you can see their eyes moving back and forth under their eyelids. During REM sleep, your brain actually about as active as when you are awake! The cells in different parts of the brain are firing and sending messages to each other. These are your dreams!

You can have dreams in other stages of sleep besides REM sleep too, but REM dreams are more common, more vivid, and more complex. No one knows exactly why we dream, but it might be to help us review and remember things that happened during the day, or it might be the brain "cleaning itself up" after a long day of thinking. Good question!

Brain Trivia

• An adult brain weighs about 3 pounds.
• Your brain is 78% water - similar to the consistency of Jello or yogurt.
• When you're born, your brain is about 10% of your body weight.
• By the time you are grown up, it's only 2%. It doesn't shrink - your body grows!
• There are about 100 BILLION neurons in an adult brain! That's about 20 times more than the number of people on the planet!
• Babies have even more neurons - about 200 BILLION!
• Each adult neuron makes 1,000 - 10,000 SYNAPSES, or connections, with other neurons.