title: Sound representation in higher language areas during language generation.
abstract: How language is encoded by neural activity in the higher-level language areas of humans is still largely unknown. We investigated whether the electrophysiological activity of Broca's area correlates with the sound of the utterances produced. During speech perception, the electric cortical activity of the auditory areas correlates with the sound envelope of the utterances. In our experiment, we compared the electrocorticogram recorded during awake neurosurgical operations in Broca's area and in the dominant temporal lobe with the sound envelope of single words versus sentences read aloud or mentally by the patients. Our results indicate that the electrocorticogram correlates with the sound envelope of the utterances, starting before any sound is produced and even in the absence of speech, when the patient is reading mentally. No correlations were found when the electrocorticogram was recorded in the superior parietal gyrus, an area not directly involved in language generation, or in Broca's area when the participants were executing a repetitive motor task, which did not include any linguistic content, with their dominant hand. The distribution of suprathreshold correlations across frequencies of cortical activities varied whether the sound envelope derived from words or sentences. Our results suggest the activity of language areas is organized by sound when language is generated before any utterance is produced or heard.
authors.affiliation: Neurosurgical Unit, Department of Clinical, Surgical, Diagnostic, and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy; Istituto di Genetica Molecolare - Consiglio Nazionale delle Ricerche, 27100 Pavia, Italy; Neurocognition and Theoretical Syntax Research Center, Institute for Advanced Studies, 27100 Pavia, Italy; and lorenzo.magrassi@unipv.it.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Magrassi
authors.affiliation: Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, Pavia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Aromataris
authors.affiliation: Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, Pavia, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cabrini
authors.affiliation: Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, Pavia, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Annovazzi-Lodi
authors.affiliation: Neurocognition and Theoretical Syntax Research Center, Institute for Advanced Studies, 27100 Pavia, Italy; and.
authors.forename: Andrea
authors.initials: A
authors.lastname: Moro
mesh_terms: D001931:Brain Mapping / Q000379:methods; D065711:Broca Area / Q000502:physiology*; D004569:Electroencephalography; D006801:Humans; D007802:Language; D009483:Neuropsychological Tests; D011932:Reading; D013067:Speech Perception / Q000502:physiology*; D018709:Statistics, Nonparametric; D013702:Temporal Lobe / Q000502:physiology*
keywords: Broca’s area; language; morphosyntax; sound envelope; temporal lobe