The human brain is a mystery, but it is also one of the mysteries that have generated most interest throughout history .

After all, it has been known for millennia that it is there that thoughts, feelings, subjective sensations and self-consciousness arise. Moreover, this group of organs is so complex that until recently those who wanted to study it could only do so passively and indirectly, that is, examine the brains of people who had already died and try to relate the symptoms expressed by this person to the anatomy of their nervous organs.

What technologies are used to study the brain and nervous system?

This had clear drawbacks: neither could this type of information be compared with what was being observed in the person’s behavior in real time (which meant, among other things, that no useful data could be obtained for the treatment of patients), nor could brain activity, which was only present in living people, be studied directly. The latter is very relevant, taking into account that the brain is formed in part by the activity in it: the characteristics of the dynamics of the nervous functioning of each person modify the anatomy of the brain .

Fortunately, today there are technologies that allow us to study not only the anatomy of the brain of living, conscious people , but also its functioning and activity in real time. These new techniques are encyclopaedia (EGG), computerised axial tomography (CT), positron emission tomography (or PET), angiography and functional magnetic resonance imaging (fRMI). The characteristics of each of these systems are discussed below.

1.Electroencephalography, or EEG

This has been one of the first methods developed to “read” the activity of the brain, that is, the patterns of electrical firing that run through it. The technique is relatively simple, and consists of leaving fixed electrodes on the person’s scalp so that these capture the electrical impulses that are captured just below to send this information to a machine. The machine collects this data and expresses it in the form of lines and peaks of activity using a graphic tracer, in the same way that seismographs work to measure the intensity of earthquakes. This record of activity is called an encephalogram .

The EEG is very simple and versatile, so it can be used to measure the activity of either a few neurons or larger areas of the cerebral cortex. It is widely used to study epilepsy cases, as well as brain waves from sleep, but because it is not very accurate it does not allow us to know exactly where in the brain these activation patterns are initiated. Furthermore, knowing how to interpret encephalographies is complicated and requires good training and education to be able to do so.

2. Computerized axial tomography, or CT scan

The computerized axial tomography , unlike encephalography, gives us a picture of the brain and its anatomy as seen from various angles, but not of its activity. That is why it basically serves to study the shapes and proportions of the different parts of the brain at a given time.

3. Positron emission tomography, or PET scan

This type of tomography does serve to study brain activity in specific areas of the brain, although indirectly. To apply this technique, a slightly radioactive substance is first injected into the person’s blood, which will leave a trace of radiation wherever it passes through. Sensors then detect in real time which areas of the brain are receiving the most radiation, which may indicate that these areas are absorbing more blood because they are being more active.

From this information a screen is recreated, the image of a brain with the most activated areas marked .

4.Angiogram

The angiogram looks a bit like PET, although in this case a kind of ink is injected into the blood. In addition, the dye does not remain in the most active areas of the brain for a while, unlike radiation, and keeps circulating in the blood vessels until it disappears, so it does not provide a picture of the brain’s activity but rather of its structure and anatomy.

Used especially to detect areas of the brain that are diseased .

5.Magnetic Resonance Imaging (MRI and fMRI)

Both the magnetic resonance imaging and its “extended” version, functional magnetic resonance imaging or fMRI, are two of the most popular brain study techniques in psychology and neuroscience-related research.

Its operation is based on the use of radio waves in a magnetic field into which the head of the person in question is inserted .

The limitations of these techniques

The use of these technologies is not without its drawbacks . The most obvious one is their cost: the machines required for their use are very expensive, and to that we must add the opportunity cost of having a space reserved in a clinic and having at least one highly qualified person who will direct the process.

In addition, the information related to the parts of the brain that are activated does not always provide much information, as each brain is unique. This means that the fact that one part of the cortex “lights up” does not necessarily mean that the part in charge of X function has been activated.