How Many Cells Does the Brain Have?

The human brain is made up of neurons, which are called brain cells. These neurons are the building blocks of the nervous system and they are responsible for the transmission of information to the brain from the body, and from the body to the brain.

In this article, we will answer the question of how many cells the human brain has, we will discuss the efficiency of the brain, as well as the differences between the human brain and the brains of other animals. The article will also address some frequently asked questions about the brain in the end.

How Many Cells Does the Brain Have?

New research has shown that the human brain has 86 billion neurons (Herculano-Houzel, 2009). Older estimates of the number of neurons in the brain suggested that there are about 100 billion neurons (Kandel et al., 2000; Ullian et al., 2001, however, newer research has confirmed the number of neurons in the brain is 86 billion. 

This may seem like a small difference in the number of neurons, but it isn’t. 14 billion neurons make a huge amount of difference, as a baboon brain has about 14 billion neurons. 

A good approximation of the number of neurons in the brain was cited by William and Herrup (1988), who estimated it as around 85 billion. With the telencephalon having 12 to 15 billion neurons (Sharrif, 1953), the cerebellum contains around 70 billion neurons (Lange, 1975), and the brainstem consists of 1 billion neurons. 

So, what are neurons?

The brain consists of brain cells called neurons that are responsible for processing and transmitting information in the brain, and from the body to the brain and vice versa. In order to communicate with each other, neurons in the brain use electrical as well as chemicals known as ions. Ions are electrically charged particles that enable neurons to communicate with each other. 

Neurons are thus said to have electrochemical signs consisting of both electrical and chemical charges. These charges change on the basis of whether the neuron is on rest or is active. When the neuron is active, it is either sending a message or receiving it (Furber, 2012). 

Neurons consist of fluids inside them that contain ions. These ions either have a positive or a negative charge. When at rest, the neuron consists of more negative ions on the inside and positive ions on the outside. This gives its membrane a negative charge. Whenever there is a signal of brain activity, positive ions rush through the channels into the neuronal membrane. When the charge is strong enough, it starts sending signals to nearby neurons to communicate with them. 

The Incredibly Efficient Human Brain

The human brain is 2.5 million gigabytes. The storage capacity of the human brain is about over 74 Terabytes, just in the cerebral cortex alone.

The memory capacity of an adult human brain on average is trillions of bytes of information. It has been reported that the cerebral cortex in the brain alone has 125 trillion synapses. Studies have found that one synapse can store around 4.7 bits of information.

It is said that the brain’s memory capacity is closer to 2.5 petabytes. This means the brain’s memory capacity is 2.5 million gigabytes! Interestingly, neurons combine so that they form many memories at a time, thus, the brain’s memory storage is ever increasing.

The brain can process up to 400-800 words per minute. Scientists have been aware of the brain’s capacity to understand speech at a rate of up to 400 words a minute and beyond for a long time now. They claim that the speech rate is not limited by the person who is listening, but by the one who is speaking. 

What makes us smarter?

The bigger and faster neurons one has, the higher the IQ. However, this is at the beginning of its research, and if the findings confirm it, we will have a newer perspective to enhance and learn about human intelligence. IQ of an individual is influenced by both – the environment as well as the genetics one possesses. 

Herculano-Houzel (2012) suggests that even though our brains are similar to a great extent to other primate brains, the most important difference between them is that we have more brain cells that also require huge amounts of energy to work as well as simply maintain!

For instance, research suggests that a quarter of our energy expenditure goes towards the maintenance of our 86 billion brain cells. This also makes the brain vulnerable. If the brain’s energy supply falls short, for even about 10 minutes, it can lead to permanent damage. No other organ in the human body is as sensitive as the brain when it comes to energy supply issues. 

Another difference s that the human brain has the component of neuroplasticity, where the human brain is influenced by environmental or genetic factors throughout the lifespan. 

Another difference is that the human brain grows rapidly during the first year of life. The human brain also has the ability to develop sophisticated linguistic skills, in which we can communicate information with others in a rapid and efficient manner. Humans also have the ability to coordinate and plan actions, as well as engage in complex decision-making. 

Memory is another distinct feature of the human brain. In which, humans tend to remember words and what they mean. Humans also have a vocalisation system which helps us in speaking what we want, and coordinate our muscles so that we can make the correct noises. 

The Human Brain Cells Compared with Other Animals

There is a huge difference between the number of brain cells, or neurons, present in the human brain as compared to other species. For instance, fruit flies have around 100 thousand neurons, mice have 75 million neurons, cat brains consist of 250 million neurons, chimpanzees have about 7 billion neurons, and elephants have 257 billion neurons. Thus, apart from elephants, the human brain has more number neurons as compared to other animals.

Conclusion

In this article, the question of how many cells the human brain has was answered, the article also discussed the efficiency of the brain, as well as the differences between the human brain and the brains of other animals. The article also addresses some frequently asked questions about the brain in the end.

Frequently Asked Questions: How Many Cells Does the Brain Have?

Is it possible to lose brain cells?

If there is any physical damage to the brain or other parts of the central nervous system, then it can disable, or even kill neurons. These damages can be caused by a stroke, which can kill neurons either on spot or they die slowly because of a lack of oxygen and required nutrition.

How many brain cells are lost each year?

Usually, an estimated figure says that people can usually lose about 10,000 neurons every day. If we add this up, it results in us losing more than three and a half million neurons a year! We start losing neurons as we approach the age of 20.

Can alcohol kill your brain cells?

Yes, alcohol can kill brain cells. Only some of those cells can be rejuvenated over time. The brain cells that continue to exist tend to compensate for the lost neurons, however the brain damage caused by this remains to be permanent.

Can brain cells burst?

The cells in the thalamus may begin “bursting” when they detect a stimulus that may require urgent attention from the brain. This “bursting” simply refers to firing off simultaneous signals to the cortex to get its attention.

References 

Furber, S. (2012). To build a brain. IEEE Spectrum, 49(8), 44-49.

Herculano-Houzel S. (2009). The human brain in numbers: a linearly scaled-up primate brain. Frontiers in human neuroscience, 3, 31. https://doi.org/10.3389/neuro.09.031.2009

Herculano-Houzel S. The remarkable, yet not extraordinary, human brain as a scaled-up primate brain and its associated cost. Proc Natl Acad Sci USA. 2012;109 Suppl 1:10661-8. doi:10.1073/pnas.1201895109

Herculano-Houzel S, Avelino-de-souza K, Neves K, et al. The elephant brain in numbers. Front Neuroanat. 2014;8:46. doi:10.3389/fnana.2014.00046

Jardim-Messeder D, Lambert K, Noctor S, et al. Dogs have the most neurons, though not the largest brain: trade-off between body mass and number of neurons in the cerebral cortex of large carnivoran species. Front Neuroanat. 2017;11:118. doi:10.3389/fnana.2017.00118

Kandel E. R., Schwartz J. H., Jessell T. M. (2000). Principles of Neural Science, 4th Edn New York, McGraw-Hill, pp. 19–20

Kohl J, Jefferis GS. Neuroanatomy: decoding the fly brain. Curr Biol. 2011;21(1):R19-20. doi:10.1016/j.cub.2010.11.067

Lange W. (1975). Cell number and cell density in the cerebellar cortex of man and some other mammals. Cell Tissue Res. 157, 115–125 10.1007/BF00223234 

Shariff G. A. (1953). Cell counts in the primate cerebral cortex. J. Comp. Neurol. 98, 381–400 10.1002/cne.900980302 

Ullian E. M., Sapperstein S. K., Christopherson K. S., Barres B. A. (2001). Control of synapse number by glia. Science 291, 657–660 10.1126/science.291.5504.657

Williams RW. Mapping genes that modulate mouse brain development: a quantitative genetic approach. Results Probl Cell Differ. 2000;30:21-49. doi:10.1007/978-3-540-48002-0_2

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