With 86 billion neurons that connect to each other, the human brain is an information hub like no other. But it also consumes a lot of energy, requiring a constant flow of highly-regulated blood that carries oxygen and nutrients to all its parts. This is why cerebral blood vessels, if laid end to end, could wrap around the Earth four times.
RELATED: How to Strengthen Memory
10 - Your Brain Is Power Hungry
For a three-pound organ, the brain packs a lot of power. It interprets our five senses, controls movement and speech, and stores our memories. It also keeps us alive, breathing and beating our hearts. Its tasks are so complex, however, that the brain needs a steady supply of energy to function.
Our cerebrum handles most of the heavy lifting, making up 85 percent of the brain?s weight. Its left and right hemispheres each chip in to handle different types of thoughts. That is why artistic people may feel they are more right brained, while analytical thinkers use their left brains more.
Neuroscientists once thought the remaining 10 percent of our brain was just a bunch of empty cells. But now they know that these neurons are packed with important functions, from mopping up excess neurotransmitters to promoting and modulating synapse growth. They even help us learn, remember and dream. And they need a constant source of fuel, like the foods we consume.
9 - Neurons Are the Immortals of Cells
The brain contains 100 billion neurons that send electrical impulses to other cells, forming the basis of thought and behavior. This three-pound organ interprets the senses, initiates movement, and handles complex processes like judgment, emotion, and learning. It is tucked inside a bony shell and washed by protective fluid.
The nucleus of a typical nerve cell is large, round and euchromatic (marked by a single prominent nucleolus). Cytoplasm is abundant and conspicuously basophilic, featuring masses of rough endoplasmic reticulum traditionally called Nissl bodies (for Franz Nissl, b. 1860).
Neurons have long, thin axons that extend from their cell body and carry action potentials to other neurons. In some regions, such as the internal capsule and corpus callosum, most axons travel in one direction; in others, such as in the pyramidal cell layer of the cerebral cortex, axons crisscross back and forth within white matter.
8 - Faster Than Formula 1 Racers
In the movie Jerry Maguire, young Jonathan Lipnicki proclaimed, "My brain is bigger than yours!" But while our brains are larger in proportion to body size than those of other mammals, there is no evidence that larger brains automatically mean higher intelligence. Indeed, geniuses in their fields sometimes have smaller-than-average brains.
Your brain consists of two hemispheres connected by an area called the corpus callosum. Each hemisphere has a different set of functions, and one may be dominant, as is the case with left- or right-handedness.
Inside the brain are 86 billion neurons, or nerve cells. These communicate with each other through trillions of connections, called synapses. Each synapse contains different molecular switches that can be activated by electrical or chemical signals. The neurons in your brain can move information very fast, at about 250 miles per hour.
7 - 100,000 Miles in a Cantaloupe
The human brain weighs three pounds, has a texture like firm jelly, and contains 100,000 miles of blood vessels. This is the same distance around the world at the equator.
During brain surgery, doctors can see the blood vessels through which oxygen and other nutrients are transported within the organ. This gives neurosurgeons clues about how the brain is functioning.
Your brain can recognize a face in 13 milliseconds, which is faster than it takes to blink. In fact, the brain can process an image in as little time as it takes to form a word.
Men's brains are 10% larger than women's, but size doesn't determine intelligence. Einstein's brain, for instance, was smaller than average but he had an extraordinary intellect.
6 - 10% Is a Lie
From the ancient Egyptians to Aristotle, famous anatomists have downplayed the importance of the mysterious organ in between our ears. But recent studies have revealed that the brain does much more than control movement and speech. It also creates art, athletic prowess, morals and much more.
While the brain is a powerhouse of complex systems, it can be susceptible to simple errors. A mere five minutes without oxygen can cause cells in the brain to die, resulting in permanent damage. It is therefore critical to ensure a constant supply of oxygen.
It is widely believed that larger brains are smarter, but this just isn't true. The size of the brain isn't related to intelligence, but rather the number of connections between different areas of the brain. In fact, Albert Einstein's average-size brain was better connected than most people's. His ability to think so critically and creatively may have had something to do with his brain being so well connected.
5 - Light Bulb Under Perpetual Construction
At first glance, it seems implausible that anyone could keep a light bulb running for more than one or two years. After all, they must be subjected to a 3,000-degree temperature change in less than a thousandths of a second and can burn out even more rapidly under constant use.
Nevertheless, there is an incandescent light bulb at a fire station in Livermore that has been on more or less constantly since 1901. It is credited with being the oldest working bulb in the world and is currently still burning.
This bulb is so revered, in fact, that it has its own webcam (BulbCam) that keeps watch on the luminous flame. While the fire department hasn?t divulged how long the bulb has been on, they did say that it was moved from the hose cart house to its current location under police and fire truck escort in 1903. It even survived a remodel of the fire station in 1937.
4 - It’s a NueroAirport
There are about 86 billion neurons in the human brain, and they're hard at work turning information from our environment into electric signals that communicate with other cells. These signals travel across synapses, which are the connections between neurons. The speed of this communication varies, but it's estimated that information can ping around the brain at 250 miles per hour. That means your brain can handle A LOT of information every second, and process it faster than the best computer.
The largest part of the brain is the cerebrum, which makes up 85% of its weight. This part handles all the basics - movement, senses, temperature and judgment - as well as more complex tasks such as learning, memory and emotions. It also controls our limbs and organs.
Another important part of the brain is the brain stem, which takes care of things like breathing and keeping your heart beating. It also shuttles information from sensory organs to other parts of the brain. And it controls your body's automatic functions, such as swallowing and coughing.
Neurons are made up of cell bodies (somas) and dendrites that branch off from the soma. Cell bodies are shaped like small spheres, and their size and shape determine how they branch and extend from the soma. This determines how they are able to respond to inputs and generate electrical responses such as action potentials.
Modeling neurons in detail allows us to understand how they function. Over the years, detailed morphological models have provided key insights into hundreds of experimental findings, both at the single-cell level and the network level. For example, a detailed model of pyramidal neurons explained why different shapes of somatic excitatory postsynaptic potentials (EPSP) are produced by neurons with identical cable properties.
In our brain-mapping project, we have created models of neurons in neocortex and subcortical regions. The neurons are described using the NEURON morphology file format, which contains 3D detail about the cell body and dendritic branches. This data is imported into a computational simulation called neuroConstruct. Various cell packing patterns can be selected, such as cubic close packing for optimal density, evenly spaced packing in 3D with the center of each cell body aligned, or hexagonal planar patterns.
3 - Now that's what I call premium water
When it's hot out and you feel dehydrated, your brain sends a signal to your body that it's time for a drink. But what exactly triggers that sensation, and how does your brain make a decision about how much water you should drink? This is what Caltech assistant professor Yuki Oka is trying to find out.
The brain's primary thirst center is a deep structure called the hypothalamus. It contains special sensors that constantly monitor the concentration of sodium in your blood. When this concentration falls too low—say, because of excessive fluid loss in sweat or diarrhea—or when it rises too high, for example, from drinking too much water or eating salty food—the hypothalamus sends a message to the body: Drink some water!
This information reaches a sheet-like area of the brain called the lamina terminalis. Cells in this region then pass their verdict about the body's current water needs on to other regions of the brain. For example, the hypothalamus forwards water-related info to the part of the brain that controls your circadian clock. This tells you to drink a lot of water before bed to avoid becoming dehydrated during sleep.
It's a complex dance, and figuring out how the brain keeps track of these two different timescales is central to understanding our instinctive response to thirst. But so far scientists haven't been able to pin down the specific brain activity that drives this process.
In the study published today in Nature, Oka's team tracked the brain activity of mice with specialized thirst neurons. These neurons are stimulated by a substance called calcium, which is released when the brain receives the signals from the mouth and throat that it's time to drink water. When these thirst neurons are turned off, the mice stop drinking.
The scientists also took functional MRI scans of human volunteers as they drank water to quench their thirst and again after they were told to keep drinking even though they were already well-hydrated. They found that drinking to satisfy a real thirst was associated with activation in the anterior cingulate cortex and orbitofrontal cortex, areas of the brain involved in emotion and decision-making. But drinking water past the point where a thirst was satisfied was associated with activation in the putamen, cerebellum and motor cortex—regions that control movement and coordination.
2 - Light Bulb
In high school, you probably read about neurons, the basic units of the brain. Each cell in your body contains a neuron, which communicates with other cells by means of electrical and chemical signals. Neurons are arranged in a complicated network called the "neuron forest." You can think of it like your house's electrical wiring, but with neurons conveying information rather than electricity flowing through them.
Each neuron has a cell body, dendrites and an axon. Dendrites branch off from the cell body and form connections with other neurons. These connections are called synapses. When a neuron becomes excited, it 'fires,' sending messages across the synapses. The messages then travel to other neurons, which can receive and process the signals. Neurons can be excited in many ways, but one of the most common is when a nerve impulse passes through them.
When a nerve impulse reaches the end of a neuron, it releases vesicles at the very edge of its membrane. These vesicles act a little bit like envelopes that contain messages in need of being mailed. They suck up neurotransmitters from within the cell, fusing with them to continue the message. The neurotransmitters then cross the gap between neurons and connect with receptors on the 'post-synaptic' cell, continuing the signal.
Every minute, 750 to 1,000 milliliters of blood rushes through your brain. The cerebrospinal fluid that bathes the brain protects the delicate tissue from damage. The cerebellum handles many important functions, including movement and balance. The brain stem handles more basic tasks, such as breathing and heart beat. And the cerebrum handles higher-level thinking and emotional functions, such as problem solving, learning and memory.
Despite the myth that most people only use 10% of their brain capacity, scientists have found that your brain is very efficient. You can multitask, but it's best to concentrate on one task at a time. Switching back and forth between two different activities decreases productivity, as it takes longer to learn or complete a task. It's also harder to remember what you've just done, a fact supported by studies showing that the human brain can't hold more than a few thoughts at once.
1- Your Personal DVR
When it comes to human memory, scientists have a lot of questions. The concept of what we think of as a single memory is actually a complex construct of multiple memories from different regions of the brain. We are only beginning to understand how the brain reassembles these impressions into a coherent thought.
Scientists also know that the brain simmers with activity. The brain is a complex network of neurons that constantly fire together to create thoughts, perceptions and actions. Neurons have special branches on one end called dendrites and axons that connect them to other neurons, and they communicate via synapses – the spaces where they come close enough to touch in order to relay information. Neurons fire a combined electrical current between three and eight times per second to communicate with each other.
Each of our brains is divided into lobes, with each lobe taking on a specific task. For example, the frontal lobe handles tasks like thinking, memory storage and movement. The parietal lobe processes sensory information such as sight, touch and smell. And the occipital lobe deals with things that you can see, including eye movements and short-term memory.
The hippocampus is responsible for encoding new memories into long-term memory. It was once believed that if you lost your hippocampus, you would have very short attention spans, but more recent research has shown that your hippocampus can adapt to the loss of its function.
Once the memory is encoded in the brain, it is stored for later use. This process is known as encoding, storage and retrieval. During the encoding stage, the brain uses a process called long-term potentiation or spike-timing dependent plasticity, which involves persistent changes in the strength of connections between neurons – or synapses. Neurons that are used more often become stronger, while those that are not get weaker.
The storage part of the memory process occurs in two parts – short-term memory and working memory. Short-term memory is temporary, such as a phone number you remember for only a few seconds. Working memory is a more longer-term memory where you store information so you can manipulate it, such as when you are working on a problem.
