The Journal of Neuroscience, August 29, 2007, 27(35):9252-9261; doi:10.1523/JNEUROSCI.1402-07.2007
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Behavioral/Systems/Cognitive
Effects of Selective Attention on the Electrophysiological Representation of Concurrent Sounds in the Human Auditory Cortex
Aurélie Bidet-Caulet,1,2,3
Catherine Fischer,1,2,3,4
Julien Besle,1,2,3
Pierre-Emmanuel Aguera,1,2,3
Marie-Helene Giard,1,2,3 and
Olivier Bertrand1,2,3
1Institut National de la Santé et de la Recherche Médicale, Unite 821, Lyon F-69500, France, 2Institut Fédératif des Neurosciences, 3Université Lyon 1, and 4Department of Functional Neurology and Epileptology, Neurological Hospital, Lyon F-69000, France
Correspondence should be addressed to A. Bidet-Caulet, Institut National de la Santé et de la Recherche Médicale, Unite 821, Brain Dynamics and Cognition, Centre Hospitalier le Vinatier, 95 Boulevard Pinel, 69500 Bron, France. Email: bidet-caulet{at}lyon.inserm.fr
In noisy environments, we use auditory selective attention to actively ignore distracting sounds and select relevant information, as during a cocktail party to follow one particular conversation. The present electrophysiological study aims at deciphering the spatiotemporal organization of the effect of selective attention on the representation of concurrent sounds in the human auditory cortex. Sound onset asynchrony was manipulated to induce the segregation of two concurrent auditory streams. Each stream consisted of amplitude modulated tones at different carrier and modulation frequencies. Electrophysiological recordings were performed in epileptic patients with pharmacologically resistant partial epilepsy, implanted with depth electrodes in the temporal cortex. Patients were presented with the stimuli while they either performed an auditory distracting task or actively selected one of the two concurrent streams. Selective attention was found to affect steady-state responses in the primary auditory cortex, and transient and sustained evoked responses in secondary auditory areas. The results provide new insights on the neural mechanisms of auditory selective attention: stream selection during sound rivalry would be facilitated not only by enhancing the neural representation of relevant sounds, but also by reducing the representation of irrelevant information in the auditory cortex. Finally, they suggest a specialization of the left hemisphere in the attentional selection of fine-grained acoustic information.
Key words: auditory cortex; attention; intracranial EEG; human; event-related; steady-state; concurrent sound
Received March 29, 2007;
revised June 19, 2007;
accepted July 11, 2007.
Correspondence should be addressed to A. Bidet-Caulet, Institut National de la Santé et de la Recherche Médicale, Unite 821, Brain Dynamics and Cognition, Centre Hospitalier le Vinatier, 95 Boulevard Pinel, 69500 Bron, France. Email: bidet-caulet{at}lyon.inserm.fr
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