How many neurons does the human brain have?

If you are wondering what is the total number of neurons you have... here is the answer.

If the human brain is the set of organs that houses thought, it may be thought that all our mental processes are actually the consequence of the fact that there are many nerve cells functioning in our head. However... how many neurons are there in the brain of an average human being?

Knowing this is not easy, since on a microscopic scale the variation in the number of cells is always very large and it is very easy to make a mistake in the measurements. However, it is currently estimated that the brain of an adult person usually has almost one hundred billion neurons. Or, expressed in numbers, between 86.000.000.000 and 100.000.000.000 (10 raised to 11).

But these figures are not as important as one might at first suppose...

• Recommended article: "Parts of the human brain (and functions)".

Massive numbers of neurons and synapses.

This figure may seem overwhelming, but it doesn't hurt to remember that what really makes the human brain such a complex system is not the number of neurons a person has, but the way in which these neurons interact with each other..

The variability of things that can happen in our brain does not depend so much on the number of neurons as on what they do, the way they communicate. And to know this we have to take into account what happens at the points where these nerve cells connect with each other. These places are called synaptic spaces, and the same neuron can be associated with several of them, through which it receives and sends information.

How many synaptic spaces are there in the adult human brain? 10 times 14. That is: 100.000.000.000.000. In addition, each of these synaptic spaces hosts a lot of events at once: thousands of particles called neurotransmitters are emitted and captured by the neurons that share the synaptic space, and depending on the type of neurotransmitters and their quantity, the neurons will be activated following one or another frequency pattern.

Age also counts

Another aspect to take into account when considering how many neurons the human brain has is that the number of neurons varies depending on the age of the human brain. this number varies depending on the person's age.. The brain of newborns is not much smaller than that of an adult person, and has a significantly higher number of neurons. However, these are nerve cells that are not very well connected to each other, and that is why many of them are not yet fully functional.

During the first two decades of life, the maturation process of mental processes has to do with favoring the neurons that are used to connect with each other, not with increasing the number of nerve cells. What makes our ability to think in abstract terms increase during puberty and adolescence is not that new parts of the brain are born or that the number of neurons grows, but that the existing ones are more efficient. This is reflected in a process called myelination, whereby large regions of the brain turn white.

This color is a sign that the axons, the parts of the neuron that "stretch" to reach distant neurons, are beginning to spread to many parts, since this part of the nerve cell anatomy is covered by a whitish substance called myelin.

As for the number of neurons in the brain, just after the first months of life, when large numbers of neurons are already beginning to connect massively, the human body causes many of them to die.. In this way, the material from which these unused nerve cells are made can be reused for other things.

How many neurons do other animals have in their brains?

As an example, or as a curiosity, we can compare those 100,000,000,000,000 neurons in the human brain with the number of nerve cells that other animal species are estimated to have on average.

• Bee: 960.000
• Frog: 16.000.000
• Cat: 300.000.000
• Raccoon: 453.000.000
• Rhesus macaque: 480.000.000
• Chimpanzee: 6.200.000.000
• African Elephant: 11.000.000.000

What are neurons like?

If after reading all this you have realized that you don't even know very well what a neuron is, you can read this article to see what their structure is like and what the main types of neurons are, you can read this article to see how is its structure and what are the main types of neurons.:

Bibliographical references:

• Saladin, Kenneth (2011). Human anatomy (3rd ed.). McGraw-Hill.
• Shepherd, GM (1994). Neurobiology. Oxford University Press.
• Triglia, Adrian; Regader, Bertrand; Garcia-Allen, Jonathan (2016). Psychologically speaking. Paidós.