How NeurOptimal software works
(NB: the description below of the neurofeedback as implemented by the NeurOptimal software is inevitably simplified, and cannot fully account for the subtlety of the mathematical calculation when analyzing the brain signal, nor for the subtlety of the effects produced on the brain. The effects described below are a plausible hypothesis given the current state of knowledge on brain function, but they are difficult to demonstrate. This hypothesis only binds the ADNF.)
During a neurofeedback session, the NeurOptimal software analyzes in real time the electrical signal produced by the person's brain in each cerebral hemisphere. This complex EEG signal can be broken down as the superimposition of 60 regular signals made up of one to 60 oscillations per second, with the amplitude of these oscillations constantly varying. These regular frequency signals ranging from 1 to 60 Hz are grouped into 10 significant frequency bands for each cerebral hemisphere: signals from 0 to 6 Hz are grouped in the delta-theta band, signals from 8 to 13 Hz are grouped in the alpha band, and so on. The software then monitors in each frequency band for turbulence, i. e. a sudden change in the amplitude of the electrical signal. The sudden increase in amplitude at a given frequency means that an increasing number of neurons are suddenly recruited to let an electrical current (the nerve impulse) repeatedly pass through at that frequency. In the worst case scenario, this is a warning sign of an epileptic seizure.
When turbulence is detected, the NeurOptimal software briefly interrupts the sound of the music or film played during the session.
This micro-cut triggers the orientation response in the person's brain, which immediately interrupts the development of this turbulence. This reaction is spontaneous and unconscious, requiring no voluntary effort on the part of the person. Moreover, most often, the micro-cut is not audible consciously although it lasts long enough to be perceived unconsciously (between 20 and 200 ms).
Orientation response is a survival mechanism, also present in animals, which consists of immediately directing attention to a potential hazard when an unexpected change occurs in the flow of information received by the brain. During the neurofeedback session, this unexpected variation is the micro-cut of the music or film. For one of our ancestors hunting in the forest, it could be the cracking of a branch... To give absolute priority to the immediate observation of a potential danger, the orientation response relies on the activation of inhibitory neurons, those neurons that decrease or even block the transmission of nerve impulses by other neurons.
The current activity of the brain that would give rise to turbulence is inhibited for the acute observation of the present moment.
Following the initiation of the orientation response, a number of neurons inhibiting incipient electrical turbulence were activated and passed through a current. And a certain number of excitatory neurons (those that increase the transmission of nerve impulses) that were going to be recruited to participate in this turbulence were finally not covered by a current because the turbulence was interrupted. Memorization, which is based on the reinforcement of neural circuits, requires that these circuits are repeatedly traversed by nerve impulses. A neural connection that is regularly activated strengthens. Conversely, a neuronal connection that is no longer activated weakens and eventually eventually weakens (1). Inhibitory neuronal connections will therefore be reinforced by the micro-interruption of the music (or film) and the triggering of the orientation response. And exciting neural connections will be weakened as a result of the interruption of the detected turbulence. I
n the end, the reinforcement of inhibitory neuronal connections and the weakening of excitatory neuronal connections involved in turbulence will gradually lead the person's brain to a more balanced, less anxious functioning, leading to considerable functional improvements in some people.
In summary:
NeurOptimal software analyzes the brain signal and monitors turbulence in 8 frequency bands for each cerebral hemisphere.
When turbulence is detected, the NeurOptimal software briefly interrupts the sound of the music or film.
This micro-break triggers the orientation response, which immediately interrupts the development of turbulence.
This induces the reinforcement of inhibitory neuronal connections and the weakening of excitatory neuronal connections involved in turbulence.
In the end, the person's brain is brought to a more balanced functioning.
(1) At the risk of complicating matters a little, we can try to clarify this statement, which is only approximate. Since Donald Hebb's original hypothesis in 1949, one of the rules for strengthening neural connections seems to be confirmed:
If N1 and N2 are strongly activated at the same time (N1F and N2F ratings), their connection strengthens (N1F>>N2F).
So N1F>N2F tends towards N1F>>N2F.
Using the diagram below, let's now take a look at the context of the birth of turbulence. This context is essentially based on highly activated exciter neurons (EF) connected to each other (E1F>E2F). If turbulence is allowed to develop, the rule set out above will apply massively: the excitatory neuronal connections will strengthen (E1F>>E2F) which will make it easier for further turbulence to occur later on. This is avoided by inhibiting incipient turbulence by triggering the orientation response. This new context is essentially based on the strong activation of inhibitory neurons (I1F) connected to highly activated excitatory neurons (E2F) which participate in turbulence, these inhibitory neurons being themselves activated by excitatory neurons (E3F) stimulated by the triggering of the orientation response. The stated rule applies again (apart from the fact that its validity is still to be demonstrated for inhibitory connections): the inhibitory neuronal connections are strengthened (E3F>>I1F>>E2F) which will make it easier to inhibit further turbulence later on. On the other hand, by systematically associating the orientation response to the nascent turbulence, the stated rule applies to reinforce the E2F>I1F connections, which means that the nascent turbulence becomes capable of triggering its own conditioning inhibition (E2F>>I1F>>E2F). When triggering the orientation response, the complete learning is then summarized as: E1F>>E2F avoided for E2 neurons that could not participate in the inhibited turbulence, and E3F>>I1F>>E2F and E2F>>I1F>>E2F for those who participated in the turbulence during inhibition.
(According to the Wilson-Cowan model)
Principle of operation of classical neurofeedback software
(NB: here again, the brief description below of the neurofeedback as implemented by these software packages is inevitably simplified, and cannot fully account for the subtlety of mathematical computation when analysing the brain signal, nor for the subtlety of the effects produced on the brain.
Classical neurofeedback equipment also decomposes the electrical signal produced by the brain into various frequency bands, but they are interested in the absolute value of the amplitude of the signal in these frequency bands, and not as the NeurOptimal software only in the sudden variations of this value.
When the amplitude value increases or decreases above a certain threshold, in a manner considered desirable in reference to a "norm" of good cerebral function, the person doing the session is "rewarded" by the appearance of an appetizing consequence or the withdrawal of an aversive stimulus. For example, the sound of the movie or music increases and the image becomes clearer, or the video game car accelerates. Conversely, when the amplitude of the signal does not evolve satisfactorily, the person making the session is "punished" by the appearance of an aversive consequence or the withdrawal of an appetizing stimulus: the sound of the film or music decreases and the image is darkened, or the car of the video game slows down, etc. The sound of the film or music decreases and the image is darkened. Through this operating mode of conditioning (punishment/reward), the person learns to modulate the amplitude of his cerebral signals, a little by groping at the beginning because it is not obvious when one is "punished" to correct a cerebral signal on which a priori one has little voluntary control, except to modulate one's psychological state by seeking to relax or to concentrate, etc., by being guided.
This mode of learning by conscious control is slower than the unconscious learning implemented by the NeurOptimal software and requires a higher number of sessions of about 50% for an equivalent result.