Our brain is the central control system of our body and feelings. It is the most compact and complex system in the living world. We can not experience reality in any form without our brains. Memory is the most important part of our brain. But, memory is not a physical object like the hardware brain. It is not a place.
It is an activity, a process that enables us to store information (data), retrieve them and use them, many throughout our lives, as and when they are required. Our individuality is our responses to a given input to the brain. Since the responses of one person are never the same as another – even for twins – we are different individuals.
Presently, I am going to tell certain facts with numbers about our wonderful brain. These facts and numbers are not surmises, philosophical speculations or religious theologies. They are backed by sciences. The numbers quoted are average estimated values and there will be variations from person to person.
1) How solid is the human brain? : Human brain is not solid. It is a mass of jelly-like fats and tissues of which 74% is water. In our body, brain is the organ with maximum amount of fat. A mere 2% dehydration affects our cognitive abilities. Brain size is measured by weight as well as by volume.
2) Brain weight varies from 1.3 to 1.5 kg (2.9 to 3.3 pounds). Average brain weight of adult male is 1345 gram, while an adult female has an average brain weight of 1222 grams. Thus woman’s brain weighs 10% less than man.
3) Brain size: It varies according to body size. Average brain volume of 1273.6 cubic centimeter or cm³ (1052.9 to 1498.5 cm³) is for men and 1131.1 cm³ (974.9 to 1398.1 cm³) for women. Thus female brains are about 11% smaller in size than the males. The larger brain size of males is due to their larger body sizes.
4) Which people possess the largest brain? : Arctic indigenous peoples and the East Asians have the largest brains in the world with an average volume of 1443 cm³ followed by Europeans at 1260 cm³. Italians have the largest brains in Europe.
5) Brain cells: Like the other parts of human body, brain is composed of cells. These cells are called neurons. The neurons roughly number 86 billions, 86000 millions or 8600 crores (the previous estimate of 100,000 millions was erroneous). The neurons are connected by trillions of connections. They transmit information in our nervous systems to enable them to sense stimuli from environment and then respond or behave accordingly. Humans have more neurons per unit volume (neuron density) than any other animal.
6) Difference between human brains and those of other animals is mainly in their sizes. Brain-to-body mass ratio varies from animal to animal. It is about 2% for humans. The largest ratio is that of the shrew.
7) Do human brains feel pain? : No, they don’t. Brain contains no pain receptors. This makes it possible to carry out brain surgery while the patient is conscious. There is practically no need to anaesthetise.
8) Length of blood vessels inside the brain is close to 400 miles or 640 kilometers. Taking the average brain size to be 1200 cubic centimeters, there are 0.33 miles or 0.5 kilometers of blood vessels in one cubic centimeter (cm³) of the brain.
9) Shrinkage of human brain: Human brain has been shrinking for the last 28,000 years. This age belongs to upper Paleolithic (50,000 to 21,000 years ago) in the time scale of human prehistory. (This was the period when the human race invented pottery, harpoons, needles and saws.) What this shrinkage means and holds for the future of humankind, it is not known.
10) Ratio of brain mass to skin mass is half (0.5). Therefore, our skin weighs about 6-pounds or 2.724 kilograms.
11) Cerebrum mass: 85% of total brain mass is concentrated in cerebrum. So, cerebrum weighs near about 1158 grams or 2.55-pounds.
12) The billions of axons in the brain that connect different parts of grey matter are called the white matter. This white matter is of higher percentage for men than for women. Women have higher per cent age of grey matter (cell bodies, dendrites and axons terminals) than men.
13) How long our brain can survive without oxygen? : Brain can survive lack of oxygen for 4 minutes. It can survive for an additional 2 minutes that is up to 6 minutes if CPR is started within that time. After near about 6 minutes, the brain begins to die. Though brain makes up only 2-3 % of body-weight, it consumes 20% of the body’s resources in terms of oxygen and glucose. That is why when sugar level comes down significantly, we feel giddiness in the head.
14) Speed of neurons inside our brains: It varies from 0.5 to 120 metres per second (1.8 to 432 kilometers per hour). This means the maximum speed with which information can travel between parts of our brain is limited to 120 m/s. This is much faster than the average human walking speed of 2 to 4 km per hour and faster than Formula 1 race cars at their top speeds of 240 miles or 384 km per hour. Speed depends on which neurons are used to transmit message to brain with electrical signals.
15) Brain’s energy requirement in waking state is low, a mere 20 watts, just enough to light a low wattage dim bulb.
16) Brain waves: These waves are produced by synchronized electrical pulses from neuron masses communicating with each other. Brain waves change depending on what we do and feel. Both the frequency and amplitude of these waves vary: frequency from a low of 0.5 Hz (1Hz = 1 cycle/second) to a high of 42 Hz for gamma waves.
Brain waves reflect the pattern of brain activities. When brain waves are out of balance, we get neurological disorders. Any thing or process that changes our perception changes our brain waves. It was new for me to learn that human brain continues to send out measurable electrical wave signals for hours after our deaths. Brain waves are more active in dream state than in other states.
17) Effect of sweating on brain: Ninety minutes of sweating can shrink the brain equivalent to 1 year of aging. Do not panic; this is only temporary.
18) The neurons in our brains are not all alike. There are as many as 10, 000 different types of neurons (difference in shape, size, location, geometry, connections, astrocytes, sensor neuron, motor neuron, bipolar neuron).
19) Size of human brain at birth: A new born baby’s brain weighs 350 to 400 gm (approximately three-fourth of a pound). The brain volume at birth averages 369 cm³ and peaks at the age of 40 after which decline starts at the rate of 0.5 % per annum. The brain of a two-year old is 80% of an adult human. Henceforth, do not underestimate, undervalue little children.
20) How much power does the human brain generate? : Brain is estimated to generate 12-25 watts of electricity which is sufficient to power a low wattage LED light. If 800 million neurons are active at once, the electrical output is equivalent to about 0.085 watts of power. To charge an iPhone 5C hand-set, that holds a charge of 5.74 watt-hours, the brain would take approximately 68 hours. This is according to calculation by Gizmode’s Maddle Stone.
21) How many thoughts does human brain produce? : It is estimated that our brain produces around 70,000 thoughts per day of which 49,000 are negative. Since, 86400 seconds make a day, close to 1 thought per second is produced. Here is a prescription for your happiness and success. Kill the negative thoughts. You can do this by steady practice starting from a young age if you want to maximize benefits. No need to go to any of the so-called ‘spiritual’ gurus. In fact the whole purpose of meditation is to increase the positive energy level of brain. Meditation is not any single religion’s monopoly.
22) How many chemical reactions in human brain? : More than 100,000 chemical reactions occur in a human brain every second. These many reactions are necessitated by the need to send and receive trillions of information in one day. Number of reactions per second in human body is in billions.
23) Albert Einstein’s brain weighed 1230 grams or 2.7-pounds which is 10% lower than the average adult male brain of about 1400 gram. His cerebral cortex was thinner than normal. However, his neuron density was more than average. That made the difference.
24) Neanderthals had the largest brain size of 1600 cm³ (1500-1800 cm³) which is 10% larger than ours.
25) Comparison of brain mass: The sperm whales have the largest brain weighing about 8 kg or 18 pounds. Human brain has a mass of around 1.3 to 1.5 kg or 2.9 to 3.3 pounds, elephant’s brain a little more than 5 kg (11 lb) and bottlenose dolphin’s 1.5 to 1.7 kg (3.3 to 3.7 lb)
26) Aging brain: With advancing years, brain does not decline in all respects. It becomes better for some skills and worse for some others.
27) Mozart effect: It was believed that if you play Mozart music, your concentration and memory would improve. It is now proven that there is no such Mozart effect on human brain. Music helps to focus only for some people.
28) Utilization of human brain: Many years ago, I read that average humans use only 10% of their brain capacities. This recurring myth is popular even today and is quoted as fact. The myth originated with the studies of the psychologist and behaviorist Karl Lashley (1890-1958, is known for his work on Learning and Memory.) when he was searching for memory traces of en-grams in brain.
This myth has now been proven wrong. It is now established that over the course of an average day, humans use nearly 100% of their brains and most of the brain is active almost all the time.
29) Human memory: In Arthur Conan Doyle’s 1887 detective novel ‘A Study in Scarlet’, Sherlock Holmes declares that the human brain has a limited amount of space, like an attic, and should not be crowded with impractical facts. This has been proven to be totally untrue. Human brain is very different from an attic.
Human brains have nearly unlimited storage because they do not work like hard drives, attics or bookshelves. Memories are not stored in a single place but are reconstructed dynamically from various areas in the brain. You can say, memory is there everywhere (omnipresent). This enables the brain to store an unlimited amount of information for an indefinite period of time. We can not fill our memory space within our lifetimes. One estimate gives the memory of human brain to be a million gigabytes (E+15 bytes).
Our brain stores memories in various ways that help it to prioritize what is important and what is not. Brain memorizes for a reason. There are different types of memories: sensory memory, short-and long-term memory. When you memorize a passage, it goes into long-term memory. That is why you can recollect it effectively. If you read the same passage, it goes to short-term memory.
You can not will a memory to be deleted. But, memories can be completely forgotten. There is no such thing as photographic memory though there are individuals with extremely high recall abilities.
30) Extra dieting can make the brain eat itself. It is good practice not to do dieting based on what you read on internet. Internet is not accountable.
31) Multitasking makes brains less productive and creative. This is what happens with full-time housewives and public relations people.
32) Human intelligence (IQ): Some researchers say, it is rising in most parts of the world. Others suggest, human intelligence has declined since Victorian Era. There are researches which say our average IQ has been declining steadily from its initial value of 1.6 and we reached our intellectual peak 2000 to 6000 years ago. There are research reports that suggest, genetic potential for smartness is on the decline and environment seems to be trumping over genetics.
33) Intelligence and brain volume appear meaningfully related with larger brains predicting higher intelligence. The correlation coefficient lies between 0.3 and 0.4 and is stronger for adults and females than for children.
34) Does anything happen to women’s brain during pregnancy? : Yes, something happens. It shrinks temporarily and returns to its normal size 6 months after delivery. Pregnant women are known to forget certain things.
35) The transient feelings of strength, power and ecstasy that accompany orgasm is caused by the release of large amount of dopamine chemicals. Brain scan, during orgasm, looks as though some one is shooting heroine. No wonder, fertility goddesses were patronized by rulers and the rich. This also reminds me of the tantric teacher Rajneesh and his immense popularity with foreigners. His popularity went to such an extent, that he was compelled to shift his headquarters from Pune-Poona to somewhere in the US state of Oregon.
36) Our brain is a big chemist: Brain produces more than 50 identified active drugs. Some of these are associated with memory, some with intelligence and some others are sedative.
37) On a typical day of the brain, trillions of messages are sent and received. Neurons “talk to” one another using chemical as mediums. ‘Happy Messengers’ carry happy messages and ‘Sad Messengers’ carry gloomy messages. Nerve centers receive input from both the types of messengers. If the input is balanced, things run smooth and even.
38) Intensive use of mobile phone can cause certain types of brain cancer.
By Dr. Sachidanand Das