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PublicationExploring the brain - N°62

Clefs CEA No N°62 – Parution : Autumn 2014
This exploration of cerebral space and time constitutes a three-fold challenge. The first is instrumental and methodological ; the second is experimental ; the third is conceptual and theoretical. In all of these fields, CEA teams are at the vanguard. Their contributions to the development of brain imaging instrumentation, to experimental and theoretical approaches, to biomarkers or to exploratory and therapeutic interventions, give them pride of place on the international stage.

 

Foreword

Carried by the strategic vision of great pioneers, CEA has been involved in brain research for over fifty years. This 62nd issue of Clefs CEA is the best occasion to come back on the latest advances of these works, undertaken most of the time in partnership with other research organizations such as Inserm (the French National Institute of Health and Medical Research), CNRS (the French National Centre for Scientific Research), Inria (the French National Institute for Research in Computer Science and Control), the Collège de France, and Paris-Sud University.

 

The complexity of the nervous system: a challenge for neuroscience

Our consciousness of the world and of ourselves is unequivocal and coherent and is, to us, selfevident. However, the human  brain, from which this consciousness originates, consists of a host of distinct elements. How is one to create order in and give meaning to this assembly of molecules, cells, synapses and other connections, networks and systems?

 

I - NON-INVASIVE EXPLORATION OF THE BRAIN

The cerebral exploration techniques which use Magnetic Resonance Imaging (MRI) can currently be divided into three main categories. Anatomical imaging provides details, even very fine details, on the shape and volume of the various parts of a brain. For its part, functional imaging produces maps of brain activity in various conditions or in response to a variety of stimuli, while one of the purposes of diffusion MRI imaging is to produce maps of cerebral onnectivity. Positron Emission Tomography (PET) gives access to metabolites and neurotransmitters, while the EEG and the MEG (MagnetoEncephaloGraphy) provide valuable information about  the timing of events within the brain. All of these processes are  complementary and are often jointly used.

 

II - Development, learning and plasticity of the brain

For a very long time, the brain of the child remained a closed box. It was necessary to wait for the development of non-invasive cerebral imaging in order to be able to study how the child's brain learned to speak, read or calculate. These studies also shed light on the subtle mechanisms liable to be altered by developmental pathologies such as dyslexia or dyspraxia, and how the extremely heterogeneous and prolonged maturing of the human brain can explain the particularities of cognition in infants, children and adolescents.

 

III - Cognitive architecture and the brain

The complexity of information processing carried out by the brain is gradually being revealed by experimental studies combining functional neuroimaging with cognitive neuroscience and computational science. The information encoding and decoding operations performed by the brain are illustrated here by three main cognitive functions, that are language, consciousness and temporal cognition.

 

IV - Mental health and vulnerability

The articles of this chapter are not available

 

V - Neurodegenerative diseases

Neurodegenerative diseases are a heterogeneous group of pathologies responsible for cognitive and/or motor disorders. For most of them, the diagnosis remains uncertain and as yet there is no curative treatment.  Although some may appear in children or young adults, most become apparent in later life. Increased life expectancy is thus indicating a aforeseeable rise in the number of patients. Faced with this worrying fact, validating new therapies has become a public health priority.

 

VI - Identifying biomarkers for cerebral disorders

The international community is today coming together to collaborate on the
set-up of gigantic databases on each of the brain’s disorders. Current international efforts are concentrating on detecting biomarkers that only a computer is capable of discovering within these oceans of information. Such biomarkers could make it possible to detect certain weaknesses or the signature of a pathology, before the first clinical signs, thus considerably increasing the chances of success of a preventive therapy.

 

A change in scale for brain exploration

The scientific exploration of the brain is now entering a new era. A number of large-scale international projects are aiming to take advantage of the progress made in imaging and the information technologies in order to understand, model and simulate the working of the human brain, on all scales.

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