Like a computer: why do not the brain process the same input?

Rustling leaves, soft rain at the doors, a quietly ticking clock — muffled noises only beyond the hearing threshold. One moment we experience them, the next we don't, even if we don't seem to adjust, or the sounds do. Many experiments have shown that we have never similarly processed an incoming input, whether it be a tone, image or touch. This is real, even though it's exactly the same stimulus. This is because the effect a stimulus has on the brain regions that handle it relies on the momentary condition of the networks that lead to those brain regions.

However, the causes driving the continually fluctuating transient condition of the networks remained formerly unclear, and how such conditions remained altered or rhythmical.

Scientists at Leipzig's Max Planck Institute for Human Cognitive Brain Sciences (MPI CBS) have now pointed out that, at the moment the stimulation data enter the cérébral cortex, the responsiveness of the network state determines how intensely the brain responds to the stimuli. Depending on the network state, the subsequent stimulation production in the brain will be more or less 'exciting' in certain nerve cells of this so-called main somatosensory cortex. It implies that at the entrance to the cerebral cortex, the reaction of the brain is modulated and relies on whether the input is analyzed at the downstream level.

There is still certain interaction within the neurons of a network even though no other forces appear to be affecting us. The mechanism is not entirely still or idle, "Tilman Stephani, PhD student at the CBS of MPI and the first published in the Journal of Neuroscience, states. Alternatively, knowledge regarding our heart rhythm, metabolism, or breathing, regarding our space location, the temperature, and the internally produced thoughts are continually emerging. Still, while neural networks are separated from some information, endogenous neural activation exists. This constantly impacts the energy of various neural networks. "The dynamics of internal processes are therefore related to the excitability of the mechanism and consequently to the stimulus-response," says Stephani. "Therefore, the brain does not seem to work like a machine, where the same knowledge often means the same thing."

It turns out that cortical excitability variations do not happen entirely at the accident, but instead follow a temporal pattern: at one point excitability relies on the previous networking states and then affects them. This is termed long-range temporal adhesion or permanent conscience-correlation by scientists.

The fact that cortical excitability differs in this specific way indicates that neuronal networks are situated at a so-called "critical" environment, where a fragile equilibrium occurs between excitation and network inhibition. Past theoretical and observational work found that somehow this "criticism," in the case of knowledge processing and capacity, maybe the basic theory of brain activity. Stephani and colleagues are conclusive evidence now that this theory may indeed regulate sensory input heterogeneity in the human brain. This probably helps to conform the brain to the range of knowledge emerging continuously from the world. A single stimulation does not activate the whole body at once or dissipate very rapidly.

This remains uncertain, though, whether greater anticipation contributes to an excellent encounter. In other terms, did the test subjects experience the stimuli pressure equally due to their spontaneous excitability? It is already checked in a second case."Here, however, certain mechanisms will play a role too," Stephani explains. "Attention, conclude. When you aim it at anything important, there will also be an initial, intense brain reaction. However higher downstream brain mechanisms will then preclude that from being actively interpreted."

Taking part in the tests, the participants' brains responded to thousands of tiny electric currents in sequence. This treatment was used to activate the key nerve in the arm on the participants' forearms. This, in effect, created an initial response 20 milliseconds later in a different region of the brain, the somatosensory cortex. They were able to see how quickly each particular stimuli stimulated the brain, depending on the evoked EEG patterns.