Inserm Newsroom - Press room of the French national institute of health and medical research

Menu
close
Search

Catégorie de brève: Neurosciences, cognitives sciences, neurology and psychiatry

The “still, small voice” in the brain has been found!

Joan of Arc is said to have heard voices, it’s a well-known fact. But we ourselves also hear voices, without even being mystics – and especially our own. We are constantly talking to ourselves. Where does this imaginary sound impression come from, this invented sound? Where does it resonate in our heads?

A collaborative effort between the INSERM researchers at the Lyon Centre de Recherche en Neurosciences and the Grenoble C.H.U. has just shown that our brains can react as if we were hearing someone talking to us even though no one else is in the room. The research has been published in The Journal of Neuroscience.

The team directed by Jean-Philippe Lachaux, INSERM’s Director of Research was interested in a situation particularly suited to hearing the “still, small voice”, that of reading to oneself. By directly recording the activity in the auditory regions of the brain that specialise in processing voices, the researchers were able to establish that they were active when reading to oneself, i.e. when the only auditory impression is indeed that of the still, small voice inside us.

Although this research only covers the reading situation, the researchers established the proof that it is possible to directly detect the moments in which someone is thinking, and even to know which thoughts are of a rather verbal nature.

But be aware that we are still a long way away from finding out what a person is thinking. In the long term, there are numerous potential applications, for example, to consider creating learning tools that would prevent a jumble of thoughts when they become too numerous, or in the case of depressing rumination (successive, interlinked negative thoughts that eventually preoccupy the whole attention of  those suffering from depression) or schizophrenia.

© Jean Philippe Lachaux/Inserm

Hearing the brain talking to itself. One often hears the sound of one’s own voice resonating in one’s head – when reading in the silence of a library, for example. The impression of hearing is due to spontaneous activation of the auditory parts of the cortex, those normally used to analyse the sounds that reach us. It is therefore possible to observe the brain talking to itself.

The origin of blindness identified for some types of hearing loss and visual impairment

Researchers from the Institut Pasteur, the Institut de la Vision, Inserm and the Université Pierre et Marie Curie have shed light on the origin of blindness that occurs in Usher I (the most common cause of deafness-blindness in humans). The scientists also demonstrated why the rat, the only animal model available today for this illness, does not suffer from the same blindness observed in humans. This work involves directing future research towards producing a primate animal model. The latter will then make it possible to progress towards a therapy-based approach for blindness in patients suffering from Usher I. This research was published on 8 October in the Journal of Cell Biology.

Usher syndrome is a genetic illness that causes congenital deafness and progressive visual impairment caused by retinitis pigmentosa. The prevalence rate of Usher syndrome is estimated at 1/30,000. Currently, a good level of care is provided for patients with hearing disorders. However, today, there is no treatment able to stop the end result of retinitis pigmentosa.

Research conducted by Professor Christine Petit, head of the “Genetics and physiology of hearing” research unit at the Institut Pasteur, in collaboration with Dr Aziz El-Amraoui (Institut Pasteur) and Professor José-Alain Sahel (Institut de la Vision), has provided fresh grounds for hope: researchers have just discovered the origin of retinitis pigmentosa in patients suffering from Ushers  I. It stems from a fault in the organization of cell structures essential to maintain vision, calyceal processes.  This failure is caused by the malfunction of one or several proteins; in this case, five were identified by the researchers that ensured cohesion in the calyceal processes. It was possible to observe the structure of the calyceal processes in high definition using electronic microscopic techniques (see photos).

For more information

©Copyright Institut Pasteur / Cataldo Schietroma et Vincent Michel

Hereditary neurological disorders: a gene identified in spinocerebellar ataxia

Efforts from four research teams in France (team led by Giovanni Stévanin, Inserm unit 975 “Centre of research into neuroscience at the Pitié-Salpêtrière”), theUS,Taiwanand theNetherlands, have identified the gene responsible for a hereditary neurological disorder affecting the cerebellum: type SCA22 spinocerebellar ataxia.

Almost ten years of work had previously not resulted in identifying the genes responsible for this illness.

The four research teams used a combination of genetic linkage analysis applied to the entire genome and new sequencing technology of the exome in four different patient groups. The four studies resulted in identifying three different mutations in the KCND3 gene that encodes a potassium channel. Electrophysiological studies demonstrated that the mutations led to disturbance in neuronal excitability.

For the researchers, “This study offers confirmation diagnosis for patients in these groups and can be used to target the research for treatments in these specific cases”.

This study also demonstrates the benefits of analyzing the exome, including in small groups, which have not been studied in any depth until now.

These results were published on line in the Annals of neurology review.

An atlas of human brain connections !

One of the major challenges of modern neuroscience is to define the complex pattern of neural connections that underlie cognition and behaviour. Brain connections have been investigated extensively in many animal species, including monkeys. Until recently, however, we have been unable to verify their existence in humans or identify possible tracts that are unique to human brain.

The Atlas of Human Brain Connections realized by Marco Catani and Michel Thiebaut de Schotten, researcher at Inserm, capitalizes on novel diffusion MRI tractography methods to provide a comprehensive overview of connections derived from virtual in vivo tractography dissections of the human brain.

It starts with an historical overview of the giant steps taken in neuroanatomy, from its birth more than 2000 years ago, to contemporary neuroimaging insights. Next, detailed descriptions of the major white matter connections, their function, and associated clinical syndromes are dealt with in detail. The composite maps of the atlas are an excellent anatomical resource for teaching, clinical, and research purposes. By reviewing both the basic principles of neuroanatomy, its historical roots, and its modern achievements in the field of DTI tractography, the book constitutes a valuable reference work for experienced clinicians and researchers working in the field of neurology, psychiatry, neurosurgery, and neuroradiology.

L’atlas offre un aperçu historique des grandes découvertes en neuroanatomie, depuis sa naissance il y a plus de 2000 ans, jusqu’aux récentes avancées scientifiques. Il décrit des connexions importantes de la substance blanche, leur fonction, et leurs syndromes cliniques associés. Les “cartes composites” de l’atlas sont une source d’information qui peut être utilisée pour l’enseignement anatomique, clinique et à des fins de recherche.

En examinant à la fois les principes de base de la neuroanatomie, ses racines historiques, et ses récentes découvertes dans le domaine de la tractographie des IRM DWI, ce livre est un ouvrage de référence pour les cliniciens expérimentés et les chercheurs travaillant dans le domaine de la neurologie, la psychiatrie, la neurochirurgie, la neuroradiologie et la neuropsychologie.

Search
fermer