World Brain Day was celebrated on 22 July. The brain, is an organ that remains one of the most complex and fascinating in the human body. It inspires poets and philosophers, drives artists crazy, challenges scientists, and maintains an aura of mystery that gives it status and presumption. It is governed by intricate mechanisms that control movement and interaction with the world, breathing, language or calculation. It processes senses, generates emotions, allows us to idealize trips to the moon and Mars, or create works of art.
The nervous system is intrinsically complex, composed of fundamental units such as neurons and glial cells, which communicate through synapses. The various types of cells are organized into circuits and form networks that, as a whole, generate and control behaviours and emotions.
Neurosciences have undergone impressive technological advances, which allow us to begin to understand what is at the origin of what distinguishes us as individuals, and which goes beyond genetic information. This knowledge enables us to create forms of artificial intelligence that use the capacity of brain computation in the most varied tasks.
During the past twenty years, we have realized that the human brain, even after maturation, is much more changeable and adaptable than originally thought. There is now a new look directed at the Mind as a whole, the result of brain functions and its interaction with the outside. This new paradigm gave rise to the Manifest, signed by ten neuroscientists in 2007 in the prestigious Science journal, instituting the Decade of the Mind from 2012 to 2022. This initiative went global in 2009, involving scientists from all over the world, and aims to concentrate efforts and resources in understanding the Mind in an interdisciplinary way, integrating cognitive sciences, medicine, neuroscience, psychology, mathematics, engineering, social sciences, systems biology, computing, and robotics.
This effort focuses on four major axes:
- Understanding the fundamental aspects of brain functioning, such as consciousness, memory or dreams, functions that are still major challenges.
- Identification of new strategies to optimize the diagnosis, treatment and rehabilitation of neurological and psychiatric diseases.
- Modelling of mental processes, allowing the creation of computational models that reproduce, improve and predict brain functioning, with new technological applications, in all areas of knowledge
- Investment in neuroscience education, with the objective of expanding training networks and promoting the creation of specific programmes in schools in order to have qualifications in the area.
There has been considerable progress in brain imaging techniques, especially with the appearance of functional magnetic resonance imaging or fMRI, capable of detecting variations in blood flow in response to neuronal activity. Thus, it is possible to have access to the functioning whole brain by detecting changes in the activity of specific brain zones, either at rest or during different tasks, such as memory, facial recognition, listening to music, reading, games, etc. Previous techniques such as the Electroencephalogram (EEG) already enabled changes in brain electrical activity to be detected, being crucial in the diagnosis of epilepsy, sleep disorders, or effects of anaesthesia, but the analysis is done mainly in the cortical zone (brain surface) and without the anatomical resolution of the fMRI. The combination of the information obtained through the fMRI with that of the EEG has made it possible to understand the functioning of the brain at a speed never before possible.
In addition to this anatomical and functional information, the positron emission tomography techniques (PET) allow monitoring and quantifying brain markers, namely beta-amyloid peptide or Tau protein in the brain of patients with Alzheimer's disease, contributing in an instrumental way to our understanding of the progression of the disease, and enabling monitoring the therapeutic efficacy of drugs in clinical trials.
The study of the brain has also been a major driver for the development of analysis and diagnostic technologies, motivated by the search for markers in blood and cerebrospinal fluid that reflect brain changes. The creation of models of human neurons from stem cells, derived from blood or skin, which, more recently, also involve the creation of 'mini-brains', or organoids - three-dimensional models that seek to reproduce anatomy and brain circuits - allow studies with more robust applicability.
The evolution of molecular biology and genetic manipulation techniques has been essential for the development of other study methods and neuromodulation, such as 'optogenetics', in which light (optics) is used together with the genetic modification of specific brain pathways, thus allowing to interfere with the functioning of neuronal circuits in tissues or in living organisms, and thus understand their function as never before.
In turn, there has been the development of technologies such as the Brain-Computer Interface (BCI), which allow direct communication between the brain and the command of complex functions through external devices. BCI allows the bidirectional flow of information, allowing to study, locate, assist or repair human sensory-motor or cognitive function. One example in this area is the development of exoskeletons for neuro-rehabilitation in case of amputation or paralysis.
Thus, we have entered a new era in which the changes to which the brain is subjected will be protagonists, either through interaction with the immune system and history of infections, or as a result of the social context and human relationships, or as a result of food and the microbiome, and whose impact may change the way neurosciences will dictate politics, economics and sociology in the future.
Almost 100 years after Cajal, neurons continue to be mysterious butterflies of the soul. However, as we progress in the study of the wing beat of these butterflies, we are taking giant steps in understanding the Human Mind.
* The celebration of World Brain Day, which takes place on 22 July, was proposed by the World Neurology Federation in 2014.
Luísa V. Lopes, Neuroscientist, Institute of Molecular Medicine, Faculty of Medicine of Lisbon
Tiago Outeiro, Neuroscientist, University Medical Centre Goettingen
‘Las neuronas son como misteriosas mariposas del alma, cuyo batir de alas quién sabe si esclarecerá algún día el secreto de la vida mental.’
Ramón y Cajal,(1852-1934), Spanish neuroanatomist, considered the father of modern neuroscience.