Fundamental advances in French research in the field of neurosciences
The neurosciences have made spectacular progress in France over the last ten years. The field relies on a variety of disciplines such as neurobiology, psychology and ethology in order to understand better how the brain functions. Researchers have a range of techniques at their disposal for examining the nervous system, such as brain imaging and powerful microscopes. Ever-more detailed observation of the brain should help to arrive at a better understanding of how it functions and assist in the design of new therapeutic tools. Some fundamental questions lie behind recent discoveries made by researchers at the CNRS (National Scientific Research Centre), INSERM (National Institute for Health and Medical Research) and the CEA (Atomic Energy Commission).
How does the brain work? The answer to this question is one of the major challenges of the 21st century. In addition to the hope of finding appropriate solutions to certain types of disability, psychiatric problems (such as depression, schizophrenia and autism) and neurodegenerative diseases (such as Parkinson’s or Alzheimer’s), an understanding of the brain helps to explain the way in which individuals interact with each other and their environment.
Thanks to the development of scanners, computer technology and molecular biology, it has become possible to observe brain activity in real time and view the areas associated with an extremely diverse range of mental operations. Brain imaging systems make it possible to see what another person can see by following the activity of their visual areas on the screen. Some software programs, such as those of the Institute for the Brain and Spinal Cord in Paris, make it possible to analyse the images obtained through traditional magnetic resonance imaging (MRI) in more detail than the human eye can. The recent MRI technique known as "tractography" makes it possible to study the connections between different areas of the brain, rather than looking at each area in isolation.
Is it possible to see emotions or a specific thought using brain imaging? According to Stanislas Dehaene, director of the CEA-INSERM cognitive neuro-imaging laboratory in Orsay, "Recent experiments have shown that it is possible to decipher whether a subject is thinking of an action word or not, or whether he is remembering the figure 2 or the figure 8. These results, however, are feats achieved in the laboratory and they require close cooperation from the subject: they are not ready to be applied without the person knowing! There is no need to worry, therefore, as far as individual liberties are concerned, but it does represent a great hope for people who are tetraplegic or who suffer from locked-in syndrome: with the help of brain-machine interfaces they will soon be able to order a computer or robot to do something simply by thinking."
Diseases of the brain are frequent, often severe and diverse in terms of both symptoms and cause. Neurological infections and psychiatric problems affect an increasing proportion of the world’s population each year. Scientists are exploring every possible avenue to find ways of curing the brain: neuron grafts, repair proteins, therapeutic electrostimulation of areas of the brain, the drugs of the future and many more.
In 2007, a CNRS team at the Institute of Cell Physiology and Biology in Poitiers successfully grafted nerve fibres from embryonic neurons into the brain of an adult mouse. This work has paved the way for new strategies for rebuilding damaged pathways in the central nervous system and treating certain neurodegenerative diseases such as Parkinson’s or Huntington’s.
Another feat was achieved last year by the team at the Neurobiology of Adaptable Processes laboratory on a rat with a brain lesion that was disturbing its control of movements. By injecting it with a cerebral protein from the neurotrophin family, new neural connections were created in the damaged area. This experiment offers great hope, in particular for treating head injuries and cerebrovascular accidents.
As well as using these new techniques, researchers are continuing to explore possible pharmacological avenues, in particular for combating Alzheimer’s disease, which affects memory, language and the ability to make judgements. The current treatments for these symptoms target acetylcholinesterase, an enzyme that is essential for transmitting the nerve signals in charge of these cognitive functions.
The team at the Jean-Pierre Ebel Institute of Structural Biology in Grenoble, working in conjunction with an Israeli team, successfully observed acetylcholinesterase in action in August 2008. These results were supplemented in 2009 by a major discovery: that of a molecule which, when injected into sick mice by a joint French and American team, led to the cognitive capacity that had been lost being recovered.
Psychiatric illnesses are also being examined. Scientists at the Institute of Genomics in Montpellier (CNRS) have just proven the capacity of a new synthetic molecule to block the central receptor in the brain for vasopressin, a hormone involved in depression. Another promising avenue is deep brain stimulation. This technique, which is designed to treat Parkinson’s disease, consists of implanting two electrodes in the brain and then connecting them to a stimulator placed beneath the skin. Deep brain stimulation, which is being tested in various laboratories in France, is also raising widespread hopes for the treatment of obsessive compulsive disorders.