Brain plasticity in interpreters
Narly Golestani (Functional Brain Mapping Lab, Département des Neurosciences Fondamentales, CMU, University of Geneva), Barbara Moser-Mercer (ETI/UNIGE), Alexis Hervais-Adelman (Functional Brain Mapping Lab
Departement des Neurosciences Fondamentales, CMU, University of Geneva), Christoph Michel (Laboratoire de Cartograhie, Département de Neurologie, University Hospital, Geneva), Patric Hagmann (CHUV and EPFL)
Simultaneous interpreters are highly trained not only in that they speak at least two languages fluently, but also in that they are able to perform active, ‘on-line’ switching between languages as they listen to one (perception) while speaking in another (production). In other words, they are able to very actively make use of working memory resources, in that they are able to constantly switch from one language to the other and back while interpreting what they hear simultaneously, and also to juggle between modalities as they produce speech (output) in the language that they are interpreting into while at the same time listening (input) to the language that they are interpreting from. Studies in the acquisition of expertise in highly complex cognitive skills suggest that structural changes may be responsible for perfecting such complex skills (Ericsson, 2001; Moser-Mercer, 2000; Moser-Mercer, Frauenfelder, Künzli & Casado, 2000). Further, it has been proposed that the neural representation of first and second languages converge in bilinguals, and that language production, switching and control are dynamic processes involving cortical and subcortical structures that make use of inhibition to resolve lexical competition and to select the intended language (Abutalebi & Green, 2007, J of Neurolinguistics, 20, 242-275). Existing functional brain imaging data on language switching and control in non-experts shows the involvement of brain regions thought to be involved in translation and in the ‘control’ aspects of speech, including the anterior cingulate and dorsolateral prefrontal cortices (Price et al, 1999, Brain, 122, 2221-2235), as well as subcortical regions such as the left caudate nucleus (Crinion et al, 2006, Science, 312, 1537-1540), and maybe also regions involved in speech articulation, including the anterior insula, cerebellum, and supplementary motor area. In the proposed study, we expect to find experience-dependant changes in the shape and/or size of the above regions. We will attempt to reveal such changes by showing convergence of results using a variety of different morphometry tools such voxel-based morphometry (VBM), analyses on automatically segmented sulci and gyri, and manual segmentation of regions of interest (e.g.; see Golestani et al, 2002: Neuron, 35(5), 997-1010, Golestani et al, 2007: Cereb Cortex, 17(3), 575-82).
Simultaneous interpretation is an extremely demanding task that requires exquisite control of the language system in order to comprehend and produce speech concurrently in two different languages. As part of this research project we have found separable roles for networks implicating the three main structures of the dorsal striatum: 1) the pallidum, with the thalamus, ACC and SMA, is implicated in the control of speech output while monitoring both one’s own output and an input stream, 2) the head of the caudate, in combination with the anterior IFG and pre-SMA is implicated in accessing lexical alternatives for translation[A1] and 3) the putamen, alongside the medial rostral prefrontal cortex is implicated in the monitoring and management of simultaneous streams of different languages. Our findings reinforce the evidence for the crucial role of a fronto-basal-ganglia circuit in multilingual language control, overlapping with the network implicated in more general executive control (50).
Fonds National Suisse/Swiss National Science Foundation, Grant 320000-122085 (2008-2011)
Publications and Presentations:
Moser-Mercer, B. (2008). Skill acquisition in interpreting: A human performance perspective.” The Interpreter and Translator Trainer 2(1), 1-28.
Moser-Mercer, B. (2010). The search for neuro-physiological correlates of expertise in interpreting. In: G.M. Shreve, & E. Angelone (Eds.), Translation and Cognition (pp. 263-287). Amsterdam: John Benjamins.
Golestani, N., Moser-Mercer, B. , Hervais-Adelman, A.G., Murray, M., Frauenfelder, U., Meuli, R., Hageman, P., Scott, S., & Michel, C. (2010a). Experience dependant brain structural plasticity in simultaneous language interpreters. Poster presented at the 5th Alpine Brain Imaging Meeting, Champéry, Switzerland.
Golestani, N., Moser-Mercer, B. , Hervais-Adelman, A.G., Murray, M., Frauenfelder, U., Meuli, R., Hageman, P., Scott, S., & Michel, C. (2010b). Experience dependant brain structural plasticity in simultaneous language interpreters. Poster presented at the CNS (Congress of Neurosurgeons) Annual Meeting, San Francisco, California, October 16-21, 2010.
Hervais-Adelman, A.G., Moser-Mercer, B., Golestani, N., & Michel, C. (2011). The neural basis of simultaneous interpretation: A functional magnetic resonance imaging investigation of novice simultaneous interpreters. Poster presented at the 8th International Symposium on Bilingualism (ISB 8), Oslo. This poster was awarded 1st place in the Cambridge University Press Poster Awards at ISB 8.
Hervais-Adelman, A.G., Moser-Mercer, B., Michel, C., Grouiller, F., & Golestani, N. (2010). The neural substrates of simultaneous interpretation. Poster presented at the 16th Annual Meeting of the Organization for Human Brain Mapping, Barcelona.
Hervais-Adelman A.G., Moser-Mercer, B. & Golestani, N. (2011) Executive control of language in the bilingual brain: Integrating the evidence from neuroimaging to neuropsychology. Front. Psychology 2:234. doi: 10.3389/fpsyg.2011.00234 (OpenAccess here)