title: A trade-off between somatosensory and auditory related brain activity during object naming but not reading.
abstract: The parietal operculum, particularly the cytoarchitectonic area OP1 of the secondary somatosensory area (SII), is involved in somatosensory feedback. Using fMRI with 58 human subjects, we investigated task-dependent differences in SII/OP1 activity during three familiar speech production tasks: object naming, reading and repeatedly saying "1-2-3." Bilateral SII/OP1 was significantly suppressed (relative to rest) during object naming, to a lesser extent when repeatedly saying "1-2-3" and not at all during reading. These results cannot be explained by task difficulty but the contrasting difference between naming and reading illustrates how the demands on somatosensory activity change with task, even when motor output (i.e., production of object names) is matched. To investigate what determined SII/OP1 deactivation during object naming, we searched the whole brain for areas where activity increased as that in SII/OP1 decreased. This across subject covariance analysis revealed a region in the right superior temporal sulcus (STS) that lies within the auditory cortex, and is activated by auditory feedback during speech production. The tradeoff between activity in SII/OP1 and STS was not observed during reading, which showed significantly more activation than naming in both SII/OP1 and STS bilaterally. These findings suggest that, although object naming is more error prone than reading, subjects can afford to rely more or less on somatosensory or auditory feedback during naming. In contrast, fast and efficient error-free reading places more consistent demands on both types of feedback, perhaps because of the potential for increased competition between lexical and sublexical codes at the articulatory level.
authors: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, London WC1N 3BG, United Kingdom, m.seghier@ucl.ac.uk.
authors: Mohamed L
authors: http://orcid.org/0000-0002-1146-8800
authors: ML
authors: Seghier
authors: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, London WC1N 3BG, United Kingdom.
authors: Thomas M H
authors: TM
authors: Hope
authors: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, London WC1N 3BG, United Kingdom.
authors: Susan
authors: S
authors: Prejawa
authors: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, London WC1N 3BG, United Kingdom, Wolfson College, University of Oxford, Oxford OX2 6UD, United Kingdom, and.
authors: 'Ōiwi
authors: '
authors: Parker Jones
authors: School of Psychology, University of East London, Water Lane, London E15 4LZ, United Kingdom.
authors: Melanie
authors: M
authors: Vitkovitch
authors: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, London WC1N 3BG, United Kingdom.
authors: Cathy J
authors: CJ
authors: Price
mesh_terms: D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods*; D011932:Reading; D013003:Somatosensory Cortex / Q000502:physiology*; D013060:Speech / Q000502:physiology*; D055815:Young Adult
keywords: functional MRI; naming; parietal operculum; reading; somatosensory cortex; speech production