` Non-invasive Brain Stimulation techniques , whose maximum exponent is Transcranial Magnetic Stimulation (EMT), are a set of procedures that allow you to modulate brain activity from the outside of the head safely and painlessly. Without surgery and without introducing any medication into our body.
The Brain Stimulation Noninvasive has been used in research since the late 80s to better understand the functioning of the nervous system. More recently, they have become part of the therapeutic arsenal to treat, among others, diseases such as depression, chronic nerve pain or stroke rehabilitation.
WHAT IS NON INVASIVE BRAIN STIMULATION
Non-invasive Brain Stimulation are techniques used in leading medical centers of great prestige worldwide (Harvard University, Mayo Clinic, etc.), safe, virtually devoid of side effects and that have been approved by national agencies for the control of medicines, systems and protocols such as the FDA, the Agency of Canada, Australia and the European.
In the case of Transcranial Magnetic Stimulation, a specially designed equipment is used to locally generate a short-lived magnetic field on the scalp that induces an electrical current in the cerebral cortex. In this way we can change the neuronal activity and normalize those areas of malfunction due to a disease.
A LITTLE HISTORY
Non-invasive Brain Stimulation was first described and used in 1985 by Anthony Barker of the Department of Physical Medicine at the University of Sheffield to assess in a non-invasive and painless manner in a human being the integrity of its central motor pathways through stimulation of the cerebral cortex.
Subsequently, in 1987, he applied it in patients with multiple sclerosis, thus demonstrating the slowing of the motor pathways, as well as the advantages of this technique compared to transcranial electrical stimulation
FUNDAMENTALS OF NON-INVASIVE BRAIN STIMULATION
These techniques are based on the principle of electromagnetic induction described by Michael Faraday in 1838. An electric current is applied from a stimulation coil located on the scalp, which generates magnetic fields that penetrate to the brain with negligible attenuation. These magnetic fields induce an electric current in the neural tissue, the volume of which depends on the shape and size of the stimulation coil, the intensity of the magnetic field and the frequency and duration of the magnetic pulses produced.
These magnetic pulses produce a selective depolarization of neurons of the cerebral cortex, located between 1.5 and 2 cm below the skull.
These techniques allow us to understand how our brain works. One of the main advantages of Non-Invasive Brain Stimulation is that it can be used to “turn off” a certain area of our brain for a small fraction of a second. Therefore, it allows us to establish the causality between brain activations and different types of cognitive, sensory or motor functions.
It can also be useful for the diagnosis and treatment of clinical conditions, such as migraines and depression, or for the pre-surgical mapping of motor functions.
Non-invasive Brain Stimulation is also commonly used with an Electromyogram (EMG) that allows us to evaluate the electrical activity of the muscles and also with behavioral evaluation such as measuring reaction times.
Finally, to observe its effects directly on the brain, we can also record with EEG, fMRI, or PET simultaneously. This multimodal combination of techniques has a great scope in the analysis of how the brain works in both healthy patients and patients with any disease.