The human brain is certainly the most complex and fascinating machine in our universe. Even today there is a lot to know about its structure and how it works. It is known to consist of a network of nerve cells, areas and interconnected systems, still partly unknown.
Understanding its functioning and revealing this network of connections through a real mapping , constitutes the field of study of connectomics .
The term connectomeit was defined for the first time in 2005, in a revolutionary article, by Sporns-Tononi-Kotter as: “a complete structural description of the network of elements and connections that form the human brain”. The challenge posed by scientists is to unveil the activity of as many as 100 billion neurons, considering that there are a million times more connections in the brain than there are letters in our DNA!
A few years later, in 2009, the United States, Europe, Japan and China started the Human Connectome project, with the aim of creating a detailed model of the human brain.that it included the structure-function relationships, just as suggested by the scientists who wrote the 2005 article. It started from the analysis at the cellular level up to the macroscopic study of brain areas.
Brain mapping
In order to have a clear mapping, two parallel processes based on the structure and functions of the brain had to be crossed: the structural connectome and the functional connectome.
The structural connectome identifies the “physical” connections between brain cells (neurons). These connections are made through the fibers (axons and dendrites) that branch off from the neurons, connecting different “brain areas” through connections (synapses). Knowing these brain structures helps to understand the functional aspects of neural architecture.
The functional connectome, on the other hand, provides the map of the areas of the brain that work together, regardless of the knowledge of their physical connections.
Relating the information produced by the intersection of the structural and functional connectome is the most difficult part of the scientific challenge still outstanding. In fact, if well analyzed, this information can provide clear elements both to establish pathologies of a neurological-structural nature and alterations at a functional level.
How to study the connectome
Various diagnostic techniques were used to begin brain mapping, such as CT and classical MRI, which allow us to observe the macroscopic structure of the brain in a non-invasive way.
However, we have begun to explore the functioning of the brain in activity, subjected to precise stimuli, while it thinks or acts, for example, in order to observe, in the absence of macroscopic brain alterations, the differences in the functioning of specific brain areas between healthy and affected people. from pathologies.
Modern functional neuroimaging techniques (fRMN, DTI, PET and qEEG) are progressively achieving this goal, allowing to detect changes in metabolism, brain electrical activity, blood and oxygen flow in certain areas, and the spread of water molecules present in brain tissues.
All these methods can be used to identify brain damage at the origin of diseases such as depression, anxiety, delusions and hallucinations, as they detect alterations even in brains that do not show evident macroscopic lesions, as happens for many patients with mental disorders.
What is the purpose of the study of the connectome
The study of the connectome can, therefore, revolutionize the classic division between neurological and mental diseases.
As we know, neurology and psychiatry study diseases of the nervous system. However, the neurologist deals with disorders resulting from specific lesions or deficits of the brain, which can be highlighted with the examination of the patient or with metabolic and instrumental tests. He treats, therefore, the “organic” diseases of the brain, characterized by movement, sensitivity, balance, language, memory or cognitive deficits.
The psychiatrist , on the other hand, establishes the diagnosis based on the analysis of behaviors, thoughts, emotions, environmental and psychological stresses reported by the patient. Often, patients with mental disorders do not have cerebral deficits detectable with the classic methods of investigation. For this reason, mental disorders are still defined as “functional”.
A mapping of brain connections could provide information onbrain alterations responsible for mental disorders such as depression, anxiety and psychosis, allowing more accurate diagnoses, targeted therapies and more effective than current ones.
The distinction between functional and organic diseases would therefore no longer have reason to exist.
