Did you know? - 20+ Unbelievable Facts about The Human Brain

 

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Written By

Mohd Dayan

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1.  Human Brain Weight

The human brain weighs about 3 lbs. (1.4 kilograms) and makes up about 2% of a human's body weight. On average, male brains are about 10% larger than female brains, according to Northwestern Medicine in Illinois. The average male has a brain volume of nearly 78 cubic inches (1,274 cubic centimeters), while the average female brain has a volume of 69 cubic inches (1,131 cubic cm). The cerebrum, which is the main part of the brain located in the front area of the skull, makes up 85% of the brain's weight.

2. How Many cells does Human Brain have?

The human brain contains about 86 billion nerve cells (neurons) — called "gray matter," according to a 2012 study published in the Proceedings of the National Academy of Sciences. The brain also has about the same number of non-neuronal cells, such as the oligodendrocytes that insulate neuronal axons with a myelin sheath. This gives axons (thin strands through which electrical impulses are transmitted between neurons) a white appearance, and so these axons are called the brain's "white matter." 

3. Is Brain Size Link to Intelligence?

Overall brain size doesn't correlate with level of intelligence for non-human animals. For instance, the brain of a sperm whale is more than five times heavier than the human brain, but humans are considered to be of higher intelligence than sperm whales. A more accurate measure of an animal's likely intelligence is the ratio between the size of the brain and body size, although not even that measure puts humans in first place: The tree shrew has the highest brain-to-body ratio of any mammal, according to BrainFacts.org, a website produced by the Society for Neuroscience. 

Among humans, brain size doesn't indicate a person's level of intelligence. Some geniuses in their field have smaller-than-average brains, while others have brains that are larger than average, according to Christof Koch, a neuroscientist and president of the Allen Institute for Brain Science in Seattle. For example, compare the brains of two highly acclaimed writers. The Russian novelist Ivan Turgenev's brain was found to weigh 71 ounces (2,021 grams), while the brain of French writer Anatole France weighed only 36 ounces (1,017 g).

Brain size doesn't indicate a person's intelligence.   (Image credit: Shutterstock)

The reason behind humans' intelligence, in part, is neurons and folds. Humans have more neurons per unit volume than other animals, and the only way they can all fit within the brain's layered structure is to make folds in the outer layer, or cortex, said Dr. Eric Holland, a neurosurgeon and cancer biologist at the Fred Hutchinson Cancer Research Center and the University of Washington.

"The more complicated a brain gets, the more gyri and sulci, or wiggly hills and valleys, it has," Holland told Live Science. Other intelligent animals, such as monkeys and dolphins, also have these folds in their cortex, whereas mice have smooth brains, he said.

How the brain is integrated also seems to matter when it comes to intelligence. A genius among geniuses, Albert Einstein had an average size brain; researchers suspect his mind-boggling cognitive abilities may have stemmed from its high connectivity, with several pathways connecting distant regions of his brain, Live Science previously reported.

Humans also have the largest frontal lobes of any animal, Holland said. The frontal lobes are associated with higher-level functions such as self-control, planning, logic and abstract thought — basically, "the things that make us particularly human," he said.

4.  BRAIN Initiative 

In April 2013, President Barack Obama announced a scientific grand challenge known as the BRAIN Initiative, short for Brain Research through Advancing Innovative Neurotechnologies. The $100-million-plus effort aimed to develop new technologies to produce a dynamic picture of the human brain, from the level of individual cells to complex circuits.

Like other major science efforts, such as the Human Genome Project, the significant expense is usually worth the investment, Holland said. Scientists hope the increased understanding will lead to new ways to treat, cure and prevent brain disorders.

The project contains members from several government agencies, including the National Institutes of Health (NIH), the National Science Foundation (NSF) and the Defense Advanced Research Projects Agency (DARPA), as well as private research organizations, including the Allen Institute for Brain Science and the Howard Hughes Medical Institute.

In May 2013, the project's backers outlined their goals in the journal Science. In September 2014, the NIH announced $46 million in BRAIN Initiative grants. Industry members pledged another $30 million to support the effort, and major foundations and universities also agreed to apply more than $240 million of their own research toward BRAIN Initiative goals.

When the project was announced, President Obama convened a commission to evaluate the ethical issues involved in research on the brain. In May 2014, the commission released the first half of its report, calling for ethics to be integrated early and explicitly in neuroscience research, Live Science previously reported. In March 2015, the commission released the second half of the report, which focused on issues of cognitive enhancement, informed consent and using neuroscience in the legal system, Live Science reported.

The Brain Initiative has achieved several of its goals. As of 2018, the NIH has "invested more than $559 million in the research of more than 500 scientists," and Congress appropriated "close to $400 million in NIH funding for fiscal year 2018," according to the initiative's website. The research funding facilitated the development of new brain-imaging and brain-mapping tools, and helped create the BRAIN Initiative Cell Census Network (BICCN) — an effort to catalog the brain's "parts' list." The BICCN released its first results in November 2018.

Beyond a parts list, the BRAIN Initiative is working to develop a detailed picture of the circuits in the brain. For example, in 2020, BRAIN Initiative researchers published a study in the journal Neuron, reporting that they had developed a system, tested in mice, to control and monitor circuit activity at any depth in the brain. Previous efforts could only examine circuits close to the surface of the brain. Also in 2020, the initiative's Machine Intelligence from Cortical Networks (MICrONS) program, an effort to map circuits in the cortex, launched a website where researchers can share their data, including electron microscopy images of circuits. 

Since 2019, the initiative has sponsored a photo and video contest in which initiative researchers are invited to submit eye-catching depictions of the brain. Check out the 2020 winners on the Brain Initiative website. 

5. Other Cool Facts 

• The brain can't multitask, according to the Dent Neurologic Institute. Instead, it switches between tasks, which increases errors and makes things take longer. 
• The human brain triples in size during the first year of life and reaches full maturity at about age 25.
• Humans use all of the brain all of the time, not just 10% of it. 
• The brain is 60% fat, according to Northwestern Medicine.
• The human brain can generate 23 watts of electrical power — enough to fuel a small lightbulb.
• On average, your spinal cord stops growing at 4 years old. Your spinal cord, which consists of a bundle of nervous tissue and support cells, is responsible for sending messages from your brain throughout your body.
• The spinal cord is the main source of communication between the body and the brain. ALS, or amyotrophic lateral sclerosis, causes the neurons in the brain and spinal cord to die, impacting controlled muscle movement. Another disease that affects both the brain and the spinal cord is multiple sclerosis (MS). In MS, the immune system attacks the protective layer that covers nerve fibers, causing communication problems between the brain and the body.
• It’s a myth that you only use 10 percent of your brain. You actually use all of it. (Yes, even when you are sleeping.) Neurologists confirm that your brain is always active.
• A piece of brain tissue the size of a grain of sand contains 100,000 neurons and 1 billion synapses. However, damage to neurons can have great impact. During a stroke, for example, blood is not able to get oxygen to the brain. As a result, brain cells can die, and abilities in that particular area of the brain can be lost. Similarly, Parkinson’s diseaseoccurs when the cells of a part of your brain called the substantia nigra start to die.
• The human brain can generate about 23 watts of power (enough to power a lightbulb). All that power calls for some much-needed rest. Adequate sleep helps maintain the pathways in your brain. Additionally, sleep deprivation can increase the build-up of a protein in your brain that is linked to Alzheimer’s disease.

Your brain has a big job. Be sure to take care of it.