The seizures are one of the most characteristic and recognizable symptoms in a wide variety of cases. Tremors that run through the whole body as well as altered states of consciousness (or even the loss of consciousness) are the classic characteristics of a seizure. The fact that these affect the whole body and psychological processes suggests that behind this symptom there is an abnormal functioning of the nervous system.

Specifically, the seizures are due in part to changes in the firing patterns of neurons located in the brain .

At the origin of the seizures

Seizures can be due to several causes, including high fever, degenerative brain diseases, or functional failures that produce epileptic seizures. However, beyond the specific cause, the seizures are produced by a characteristic pattern of neuronal activity . This neuronal activity is recognizable by the rhythms with which various neurons send electrical signals to other networks of nerve cells. Seizures occur because of abnormally acting neurons in the brain, which produce alterations in consciousness and the tension and relaxation of muscle groups.

What is this pattern of activity?

Basically, it is many neurons firing electrical signals at the same time . In a normal situation where the person remains conscious, the EEG readings show a pattern of activity with few ups and downs, because there are not large groups of neurons coordinated with each other to transmit information at the same time. However, during seizures, the EEG reveals large spikes in electrical activity that contrast with moments of low activity.

All this happens in a very short time, and is reflected in the typical tremors of a person with seizures. Just as tremors are actually the repeated tensing and relaxing of muscles, something similar occurs in the brain: neurons coordinate to send out shocks together, but they also do so at times when they are not sending out electrical signals. This is why the EEG readings show peaks of activity: at a given moment, the effect of many nerve cells being activated at once is not so compensated by the non-activation of other neurons, so that the overall electrical activation is far from average.

But seizures are not just characterized by having many neurons coordinated with each other. In addition, each of these neurons is firing signals with a higher frequency than usual . In other words, the nerve cells are in a clear state of excitement for the duration of the crisis.

At the same time, these synchronized neurons responsible for the anomalous functioning are causing more and more neurons to start obeying them and activating at the same time, thus magnifying the effects of the seizure each time. With the passage of seconds there will be more and more neurons in a state of constant excitation and coordinated with each other, although fortunately cases of seizures do not usually last indefinitely.

And, while we sleep…

As a curiosity, it seems that something similar happens in the moments of sleep when we are not aware of anything , while when we dream, the results shown by the encephalograms are very similar to those of an awake person.

However, these cases have already been foreseen by evolution and mechanisms have been established so that we are not forced to have convulsions while we sleep.