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Novel fMRI tasks for discourse production and semantic processing
Poster Session A, Wednesday, September 30, 11:00 am - 1:00 pm, Wangari Maathai
This poster is part of the Sandbox Series.
Pablo del Olmo1,2, Pilar Salgado-Pineda1,2, Aranza Palacios1, Peter J. Mckenna1,2, Edith Pomarol-Clotet1,2, Joana Rosselló3; 1FIDMAG Research Foundation, 2CIBERSAM ISCIII, 3Departamento de Filologia Catalana y Lingüística General, Universitat de Barcelona
Introduction: Overt discourse production remains an understudied task in functional Resonance Imaging research (Wise and Geranmayeh, 2016), perhaps out of fear of excessive head movement. However, it is one of the most naturalistic examples of language use. Additionally, previous studies have mostly used overlearnt sequences as controls tasks, raising questions on the role of syntax in previous results. On the other hand, the cortical organization of semantic processing, and its relationship to the wider language network also remains to be explained(Bookheimer, 2002). The field would benefit from robust cognitive tasks that engage semantic processing as a whole. Methods: A total of 33 healthy subjects fulfilling standard inclusion criteria completed the discourse production task while within the MRI scanner (3T Philips Ingenia). The task consists of alternating 30 second blocks of overt sentence repetition and question answering. Only two had to be excluded due to excessive movement. 34 subjects completed the semantic task, also consisting of alternating 25 second blocks of concept plausibility judgement and pseudoword same/different judgements. Functional images were acquired using a T2*-weighted echo-planar sequence. Standard preprocessing and analysis were performed with the FEAT module (FSL), with p < .05 and a cluster formation threshold of z > 3.1. Results: The discourse production vs. sentence repetition contrast yielded significant increased activation clusters in the pars triangularis and orbitalis of the left frontal inferior gyrus (MNI coordinates -56, 22, 2; z = 6.93; 766 voxels; p<0.001), the left supplementary motor area and frontal superior gyrus (MNI coordinates 0, 16, 62; z = 5.8; 1225 voxels; p<0.001), among others. The clusters found to be significant in the semantic vs. pseudoword contrast included the pars triangularis and orbitalis of the left frontal inferior gyrus (MNI coordinates -50, 32, -2; z = 4.73; 482 voxels; p<0.001), the left middle temporal gyrus (MNI coordinates -50, -22, -10; z = 4.49; 107 voxels; p<0.05) and the left superior temporal pole (MNI coordinates -42, 22, -26; z = 3.68; 100 voxels; p<0.05). Conclusions: The discourse production task seems to recruit regions traditionally associated with the language network, motor planning and speech control (Hagoort, 2014), while not generating excessive participant movement. On the other hand, the semantic task seems to tap areas previously related to semantic memory processes (Herlin et al., 2021). Both findings provide evidence in favor of the usefulness of our novel tasks in localizing these cognitive functions. References: Bookheimer, S. (2002). Functional MRI of language: new approaches to understanding the cortical organization of semantic processing. Annual review of neuroscience, 25(1),151-188. Hagoort, P. (2014). Nodes and networks in the neural architecture for language: Broca's region and beyond. Current opinion in Neurobiology, 28, 136-141. Herlin, B., Navarro, V., & Dupont, S. (2021). The temporal pole: From anatomy to function—A literature appraisal. Journal of chemical neuroanatomy, 113, 101925. Wise, R. J., and Geranmayeh, F. (2016). Sentence and narrative speech production: investigations with PET and fMRI. In Neurobiology of language (pp. 751-762). Academic Press.
Topic Areas: Language Production,