One characteristic feature of the brain is the rhythmic oscillations of neural activity in a set of frequencies ranging from the ultra-fast (0.05 Hz) and ultra-slow (500 Hz) at low frequencies. Communication and information processing between different groups of neurons depends on whether they synchronize or not. Understanding by which mechanisms communication between the different brain areas is established continues to be one of the biggest challenges of neuroscience.

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If the brain is organized hierarchically, which is the centre that determines its synchronization? At a given moment in time, the exchange of information and the communication between two groups of neurons is more effective if the state of fluctuating excitability is coordinated, then we speak of coherence. It is what is known as the principle of communication through  coherence (CTC) and is a key mechanism in the brain. Control of this coherence by the cerebral cortex is carried out on a large scale and covers long distances.  

A study by Gustavo Deco and Morten L. Kringelbach, published in Trends in Neurosciences, links the dynamic concept of coherence with that of metastability, with which they examine the wide range of brain functions through the anatomical structure underlying their connectivity. A study carried out thanks to evidence from the computational modelling of the entire brain, produced from multimodal data obtained using neuroimaging techniques.

As mentioned by Gustavo Deco, co-author of the study and ICREA researcher of the Department of Information and Communication technologies (DTIC) and head of the Computational Neuroscience research group at UPF, “with the help of the data available, both at cellular and at functional level, we have explored the potential of the fundamental principle of brain coherence to ascertain the communication mechanisms of the brain in its entirety”.

Damage to brain connectivity limits the principle of coherence

In this article, Deco and Kringelbach have taken into account the existing links between metastability and coherence, both in a healthy brain and in a sick one. ”With this we have managed to prove that coherence is an important mechanism in the brain, so that when connectivity is affected due to a mental illness or disorder, the repertoire of available routes of CTC is far more limited, with potentially serious consequences,” Deco explains.

And he continued by saying, “the evidence that arises from the study of the links between metastability and coherence in the normal, healthy brain suggests that the brain is characterized by being maximally metastable, and that that is essential to deploy the rich normal structural functional repertoire of the brain thanks to flexible modulation in the connectivity of the neural networks”.

Reference work:

Gustavo Deco, Morten L. Kringelbach (2016) “Metastability and Coherence: Extending the Communication through Coherence Hypothesis Using A Whole-Brain Computational Perspective”, Trends in Neuroscience, http://dx.doi.org/10.1016/j. tins.2016.01.001.