Press release

 

Neuroimaging of infant brains

Paris, December 6, 2002
 

In the very first months of life, the human brain already exhibits a specialization for speech processing and a memory of the native language. These conclusions were drawn from the first detailed study of functional magnetic resonance imaging (fMRI)(1) of the reaction of infant brains to speech. They are the results of collaborative research carried out at the Hôpital Necker Enfants-malades(2) and the Service Hospitalier Frédéric Joliot (SHFJ)(3) , by teams from the CNRS, CEA, Inserm and AP-HP. This study was published in the journal Science on Friday, December 6, 2002(4).

Infant brain activation images were collected while the infants listened to 20 seconds of speech alternating with 20 seconds of silence from a recording of a female voice reading a children's book. The originality of the experiment lays in the fact that the recording was played either forward or backward. Backward speech violates the properties that are universally observed in human speech and the infants can no longer recognize characteristic sounds. By comparing activated brain areas when the story is read in one direction or the other, it is possible to determine if some brain areas are already specialized in recognizing the properties of the native language.

The results obtained revealed the following:

  • just as in adults, there is a significant left-hemispheric dominance. The fact that this left lateralization is already present in infants at the age of three months strongly suggests a genetic bias in the organization of language brain areas.
  • an organization of the brain into functional regions comparable to those observed in adults carrying out similar tasks. However, the observation of a right frontal activation in adults carrying out tasks more complex than simply listening to sentences suggests that the active mechanisms of attention and effort contribute to language learning.
  • the existence of active memory retrieval mechanisms at the age of three months. Very young infants seem to already have the ability to memorize the posodic contours of their native language, well before they can actually speak.

    Language acquisition is therefore the result of a progressive specialization of a genetically predetermined network, under the influence of active attention and memory mechanisms directed at the language of the infant's environment.

    In the future, functional neuroimaging should also make it possible to visualize the development of other brain functions (vision, hearing, motor skills) and their pathologies.


    (1) Magnetic resonance is a completely noninvasive method that has been used in neuropediatric practice and research for over 20 years. More recent functional magnetic resonance imaging (fMRI) makes it possible to visualize active brain areas in response to a stimulus.

    (2) Pediatric Radiology Department, Professor Brunelle

    (3) The Frédéric Joliot Hospital Department (SHFJ) of the CEA is the only research center in Europe today that brings together the various methods of functional and atraumatic exploration in humans.
    '
    (4) Functional neuroimaging of speech perception in infants. G. Dehaene-Lambertz, S. Dehaene, L. Hertz-Pannier, Science, December 6, 2002.

    Researcher contact:
    Ghislaine Dehaene-Lambertz
    Laboratoire de Sciences Cognitives et Psycholinguistique
    Tel: +33 1 49 54 22 62

    Press contacts :
    CNRS: Martine Hasler
    Tel : +33 1 44 96 46 35
    e-mail : martine.hasler@cnrs-dir.fr
    CEA: Alexandra Bender
    Tel: +33 1 40 56 17 16
    Alexandra.bender@cea.fr
    Inserm: Séverine Ciancia
    Tel: +33 1 44 23 60 86
    ciancia@tolbiac.inserm.fr
    AP HP: Thierry Girouard
    Tel: +33 1 40 27 37 22
    thierry.girouard@sap.ap-hop-paris.fr

     
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