An anomaly in the brain's response to the human voice in autism
The human voice is rich in both verbal and nonverbal information; it forms a veritable ‘auditive face' that we learn to interpret. Our ability to perceive vocal information plays a crucial role in social interaction. In addition, a team of researchers has now shown, using functional magnetic resonance imaging, that voice perception involves specific brain areas called ‘voice areas' located in most individuals along the superior temporal sulcus.
Autism is a severe disorder of childhood development characterised by difficulties in social interactions. Behavioural studies have also shown a deficit in the perception of the human voice. To determine the cerebral basis of this disorder, researchers in the ERM 02-05 team have used functional imaging (fMRI) to study how the brains of autistic adult subjects perceive the human voice as opposed to other sounds. For this purpose the brain activity of five autistic adults and eight healthy volunteers was recorded when they listened to sound sequences alternating human voices (speech, cries, laughs, sobs, singing) and other types of nonvocal sounds (animals, bells, musical instruments, cars, etc.).
The results obtained reveal a lack of activation of the brain area specific to voice perception (the ‘voice area') in autists. In these subjects the brain areas that are activated are exactly the same for human voice sounds as for nonvocal sounds. No brain activation specific to human voice recognition could be demonstrated. In addition, when asked to say what they heard during the test, the autists reported only 8.5% of vocal sounds against 51.5% for the controls, confirming their poor ability to recognise human voices.
Earlier functional MRI studies in the visual domain had already found that autists failed to activate the brain area specialised in face processing. This new study on the voice, an auditive stimulus rich in information on the identity and emotional state of the interlocutor, demonstrates impaired social perception in the auditive domain.
These anomalies in voice and face processing are evidence that the difficulties autists experience in understanding other people's emotional states and in interacting with them may be linked to a deficit in perceiving social stimuli. These functional imaging results opens new perspectives in the understanding of disordered social interaction in autism. The existence of these perceptive impairments suggests that remedial strategies should include specific treatment of vocal and facial information, which apparently does not develop spontaneously in autists.
Source:
"Abnormal Cortical Voice Processing in Autism" - Nature Neuroscience, July 2004
Hélène Gervais1, Pascal Belin2,3, Nathalie Boddaert1,4, Marion Leboyer5, Arnaud Coez1, Ignacio Sfaello1, Catherine Barthélémy6, Francis Brunelle1,4, Yves Samson1,7 and Monica Zilbovicius1
1ERM 0205, Inserm-CEA, DRM, DSV, Service Hospitalier Frédéric Joliot, 4, place du Général-Leclerc, 91406, Orsay, France
2Centre de Recherche en Neuropsychologie et Cognition (CERNEC), Université de Montréal, Montréal, Canada
3Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Canada
4Service de Radiologie Pédiatrique, Hôpital Necker Enfants Malades, AP-HP, 149, rue de Sèvres, 75015, Paris, France
5Service de Psychiatrie, Hôpital Henri-Mondor, AP-HP, 40 rue Mesly, 94000, Créteil, France
6Inserm - Unité 619, CHU Bretonneau, 2 boulevard Tonnelle, 37000, Tours, France
7Service des Urgences Cérébro-Vasculaires, Groupe Hospitalier Pitié-Salpêtrière, AP-HP, 47, boulevard de l'Hôpital, 75013, Paris, France
This work was funded by the Fondation de France and Fondation France-Telecom (autism sponsoring)
Research contact:
Monica Zilbovicius
ERM 02-05 INSERM/CEA - Orsay
Tel.: 01 69 86 78 90, zilbo@shfj.cea.fr
| Pascal Newton CEA 01 40 56 20 97 |
Séverine Ciancia Inserm 01 44 23 60 86 |
1In collaboration with the Neuropsychology and Cognition Research Center - CERNEC - and the University of Montreal.