Search

Published: 01 February 2023 The intention to name an object modulates neural responses during object recognition tasks. However, the nature of this modulation is still unclear. We established whether a core operation in language, i.e. lexical access, can be observed even when the task does not require language (size-judgment task), and whether response selection in verbal versus non-verbal semantic tasks relies on similar neuronal processes. We measured and compared neuronal oscillatory activities and behavioral responses to the same set of pictures of meaningful objects, while the type of task participants had to perform (picture-naming versus size-judgment) and the type of stimuli to measure lexical access (cognate versus non-cognate) were manipulated. Despite activation of words was facilitated when the task required explicit word-retrieval (picture-naming task), lexical access occurred even without the intention to name the object (non-verbal size-judgment task). Activation of words and response selection were accompanied by beta (25–35 Hz) desynchronization and theta (3–7 Hz) synchronization, respectively. These effects were observed in both picture-naming and size-judgment tasks, suggesting that words became activated via similar mechanisms, irrespective of whether the task involves language explicitly. This finding has important implications to understand the link between core linguistic operations and performance in verbal and non-verbal semantic tasks. This work was supported by a Sir Henry Wellcome Postdoctoral Fellowship awarded to E.B. (Grant reference number: 210924/Z/18/Z). C.D.M received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No: 819093) and the Spanish Ministry of Economy and Competitiveness (PID2020-113926GB-I00). The authors acknowledge the Basque Government through the BERC 2022-2025 program and the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation CEX2020-001010-S.

Published:17 December 2021 The left ventral occipito-temporal cortex (vOTC) supports extraction and processing of visual features. However, it has remained unclear whether left vOTC-based functional connectivity (FC) differs according to task-relevant representations (e.g., lexical, visual) and control demands imposed by the task, even when similar visual-semantic processing is required for object identification. Here, neural responses to the same set of pictures of meaningful objects were measured, while the type of task that participants had to perform (picture naming versus size-judgment task), and the level of cognitive control required by the picture naming task (high versus low interference contexts) were manipulated. Explicit retrieval of lexical representations in the picture naming task facilitated activation of lexical/phonological representations, modulating FC between left vOTC and dorsal anterior-cingulate-cortex/pre-supplementary-motor-area. This effect was not observed in the size-judgment task, which did not require explicit word-retrieval of object names. Furthermore, retrieving the very same lexical/phonological representation in the high versus low interference contexts during picture naming increased FC between left vOTC and left caudate. These findings support the proposal that vOTC functional specialization emerges from interactions with task-relevant brain regions. Francesca M. Branzi was supported by a H2020 European Research Council grant (GAP: 670428-BRAIN2 MIND_NEUROCOMP). Clara D. Martin was supported by grants from the H2020 European Research Council [ERC Consolidator Grant ERC-2018-COG-819093], the Spanish Ministry of Economy and Competitiveness [PID2020-113926GB-I00], the Basque Government [PIBA18-29]. Pedro M. Paz-Alonso was supported by grants from the Spanish Ministry of Science and Innovation [RYC-2014-15440; PGC2018-093408-B-I00], Neuroscience projects from the Fundación Tatiana Pérez de Guzmán el Bueno, and the Basque Government [PIBA-2021-1-0003]. BCBL acknowledges support by the Basque Government through the BERC 2018-2021 program and by the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation SEV-2015-0490. The authors also acknowledge the Medical Research intramural funding (MC_UU_00005/18).