Diana López-Barroso, María José Torres-Prioris, Lucas Sedeño, Sol Fittipaldi, Agustín Ibáñez, Marcelo L. Berthier, Adolfo M. García, Estela Camara, [Torres-Prioris,MJ, López-Barroso,D, Berthier,ML] Cognitive Neurology and Aphasia Unit, Centro de Investigaciones Médico‑Sanitarias, Instituto de Investigación Biomédica de Málaga (IBIMA), University of Malaga, Malaga, Spain. [Torres-Prioris,MJ, López-Barroso,D] Area of Psychobiology, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain. [Càmara,E] Cognition and Brain Plasticity Unit, Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona, Spain. [Fittipaldi,S, Ibáñez,A, García,AM] Universidad de San Andrés, Victoria, Buenos Aires, Argentina. [Fittipaldi,S, Sedeño,L, García,AM] National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina. [Ibáñez,A] Universidad Autónoma del Caribe, Barranquilla, Colombia. [Ibáñez,A] Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibáñez, Santiago, Chile. [Ibáñez,A, García,AM] Global Brain Health Institute, University of California, San Francisco, United States. [García,AM] Faculty of Education, National University of Cuyo (UNCuyo), Mendoza, Argentina. [García,AM] Departamento de Lingüística Y Literatura, Facultad de Humanidades, Universidad de Santiago de Chile, Santiago, Chile., This work was supported by CONICET, FONCYT-PICT [2017-1818, 2017-1820], CONICYT/FONDECYT Regular [grant number 1170010], FONDAP [grant number 15150012], Programa Interdisciplinario de Investigación Experimental en Comunicación y Cognición (PIIECC), Facultad de Humanidades, USACH, GBHI ALZ UK-20-639295, and and the Multi-Partner Consortium to Expand Dementia Research in Latin America (ReDLat), funded by the National Institutes of Aging of the National Institutes of Health under award number R01AG057234, an Alzheimer’s Association grant (SG-20-725707-ReDLat), the Rainwater Foundation, and the Global Brain Health Institute. MJTP has been funded by the Spanish Ministry of Education, Culture and Sport under the FPU program (FPU14/04021) and by a postdoctoral fellowship from the University of Malaga. DLB has been supported by the Juan de la Cierva postdoctoral programme (IJCI-2017-34164) and by I+D+i Project, Andalucia and European Union Funds (FEDER) (UMA18-FEDERJA-221).
Despite its prolific growth, neurolinguistic research on phonemic sequencing has largely neglected the study of individuals with highly developed skills in this domain. To bridge this gap, we report multidimensional signatures of two experts in backward speech, that is, the capacity to produce utterances by reversing the order of phonemes while retaining their identity. Our approach included behavioral assessments of backward and forward speech alongside neuroimaging measures of voxel-based morphometry, diffusion tensor imaging, and resting-state functional connectivity. Relative to controls, both backward speakers exhibited behavioral advantages for reversing words and sentences of varying complexity, irrespective of working memory skills. These patterns were accompanied by increased grey matter volume, higher mean diffusivity, and enhanced functional connectivity along dorsal and ventral stream regions mediating phonological and other linguistic operations, with complementary support of areas subserving associative-visual and domain-general processes. Still, the specific loci of these neural patterns differed between both subjects, suggesting individual variability in the correlates of expert backward speech. Taken together, our results offer new vistas on the domain of phonemic sequencing, while illuminating neuroplastic patterns underlying extraordinary language abilities. Fil: Torres Prioris, María José. Universidad de Málaga; España Fil: López Barroso, Diana. Universidad de Málaga; España Fil: Càmara, Estela. Universidad de Málaga; España Fil: Fittipaldi, María Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; Argentina Fil: Sedeño, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; Argentina Fil: Ibañez, Agustin Mariano. Universidad de San Andrés; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Autónoma del Caribe; Colombia. University of California; Estados Unidos. Universidad Adolfo Ibañez; Chile Fil: Berthier, Marcelo L.. Universidad de Málaga; España Fil: García, Adolfo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; Argentina. Universidad de San Andrés; Argentina. University of California; Estados Unidos. Universidad de Santiago de Chile; Chile