If the human brain is the set of organs that house thought, we can assume that all of our mental processes are, in fact, the result of many nerve cells functioning in our head. However … How many neurons are there in the brain of an average human being?
Finding out is not easy, because at the microscopic scale, the variation in the number of cells is always very large and it is very easy to make errors in the measurements. Currently, however, it is estimated that an adult’s brain typically has nearly one hundred billion neurons. Or, expressed in numbers, between 86 billion and 100,000,000,000 (10 raised to 11).
But these numbers are not as big as you might think at first …
Massive amounts of neurons and synapses
This number may seem overwhelming, but it’s worth remembering that what really makes the human brain such a complex system isn’t how many neurons a person has, but the way 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, how they communicate. And to find out, we need to consider what is happening at the points where these nerve cells connect to 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 increased to 14. That is to say: 100,000,000,000,000. In addition, in each of these synaptic spaces, there are many events at once: thousands of particles called neurotransmitters are emitted and captured by neurons that share the synaptic space, and depending on the type of neurotransmitter and their quantity, the neurons will be activated according to one or the other frequency model.
Age matters too
Another aspect to consider when examining the number of neurons in the human brain is that this figure varies depending on the age of the person. The brain of newborns is not much smaller than that of an adult and has a fairly large number of neurons. However, these are nerve cells that are not very connected to each other, and many of them are not yet fully functional.
In the first two decades of life, the process of maturing mental processes is to encourage the used neurons to connect to each other, not to increase the number of nerve cells. What makes our ability to think in abstract terms potentiated during puberty and adolescence is not that new parts of the brain are born or the number of neurons increases, but that those that are there are more efficient. This is reflected in a process called myelination, where large areas of the brain turn white.
This color is a signal that axons, the parts of the neuron that “stretch” to reach distant neurons, are starting to spread to many parts as that part of the cell anatomy. a whitish substance called myelin.
As for the number of neurons in the brain, just after the first months of life, when they are already starting to connect massively large quantities of neurons, the human body kills a lot of them. In this way, the material that these unused nerve cells are made from 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 these 100,000,000,000 neurons in the human brain with the number of nerve cells estimated on average by other animal species.
- bee: 960,000
- Frog: 16,000,000
- gun: 300,000,000
- to the laundress: 453,000,000
- Rhesus monkey: 480,000,000
- chimpanzee: 6,200,000,000
- african elephant: 11,000,000,000
How are the neurons doing?
If after reading all of this you realized that you don’t even know very well what a neuron is, you can read this article to see what its structure looks like and what are the main types of neurons:
- Saladin, Kenneth (2011). Human Anatomy (3rd ed.). McGraw-Hill.
- Shepherd, GM (1994). Neurobiology. Oxford University Press.
- Triglia, Adrián; Regader, Bertrand; García-Allen, Jonathan (2016). Psychologically speaking. Paidós.