ORIGINAL RESEARCH article
Front. Aging Neurosci.
Sec. Neurocognitive Aging and Behavior
Volume 17 - 2025 | doi: 10.3389/fnagi.2025.1547162
Beyond the Left Cerebral Hemisphere: Bilateral Language Lateralization in Healthy Aging and Its Clinical Implications
Provisionally accepted- 1Interdisciplinary Center for Neuroscience, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, Santiago, Chile
- 2Exercise and Rehabilitation Sciences Institute, School of Speech Therapy, Faculty of Rehabilitation Sciences, Universidad Andres Bello, Santiago, Chile., Santiago, Chile
- 3Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile., Santiago, Chile
- 4Department of Radiology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile., Santiago, Chile
- 5PhD Program in Health Sciences and Engineering, Universidad de Valparaiso, Valparaiso, Chile., Valparaiso, Chile
- 6Queensland Aphasia Research Centre, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia., Brisbane, Chile
- 7Departamento de Fonoaudiología, Facultad de Medicina, Universidad de Chile, Santiago, Chile., Santiago, Chile
- 8Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, Netherlands
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Background: Functional MRI (fMRI) studies conducted on young adults reveal a predominantly leftlateralized cortical language network during semantic and phonological processing (SP and PP, respectively). Both linguistic dimensions have been advanced as potential cognitive markers of pathological aging. However, the neural mechanisms underlying SP and PP among healthy older adults remain poorly understood.Aim: This study aimed to investigate the dynamics of language lateralization among native Spanishspeaking older adults in relation to their behavioral performance in specific semantic and phonological tasks.Methodology: Twenty-eight healthy, right-handed older Chilean adults (mean age: 67.7, SD±: 7.44, range: 60-87) took part in an fMRI session during which they performed semantic and phonological tasks. They were also evaluated for overall language performance using the Spanish version of ScreeLing and verbal fluency tasks. A fixed-effect analysis was performed to explore group-level differences. Standard regression analyses were also used to assess the association between brain activation and language performance.Results: Both SP and PP elicited bilateral activation in the pars triangularis and opercularis of the inferior frontal gyrus (IFG) and the superior temporal gyrus. Activation was also observed in the left inferior parietal gyrus. Semantic fluency performance was significantly associated with activation in the right angular gyrus and the pars opercularis of the IFG. In contrast, phonological fluency was associated with bilateral activation in the IFG pars orbitalis.Conclusions: Among healthy older adults, SP and PP recruit bilateral language-related brain regions, potentially reflecting compensatory mechanisms associated with normal aging. Notably, the IFG pars orbitalis may play a distinct role in supporting phonological fluency, despite not being a region traditionally linked to PP. Further research is needed to clarify the contribution of this region to phonological performance among aging adults.
Keywords: Aging, semantics, phonology, NEURAL BASIS, functional MRI
Received: 17 Dec 2024; Accepted: 03 Jul 2025.
Copyright: © 2025 Toloza-Ramirez, Santibanez, Arraño-Carrasco, Zunino- Pesce, Julio-Ramos, Copland, Quezada and Mendez Orellana. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Carolina Patricia Mendez Orellana, Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, 3015 CE, Netherlands
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