Presentation
Search Abstracts | Symposia | Slide Sessions | Poster Sessions | Lightning Talks
Differentiation of the Role of the IFG and STG in Overt and Covert Speech Using fNIRS
Poster A70 in Poster Session A, Tuesday, October 24, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
Jacqueline Cummine1, Dima Alsaigh1, Talah Hasanni1, Mitchell Holmes1, Kulpreet Cheema1, Amberley Ostevik1, Truc Huynh1, Sarah Saju1, Torrey Loucks1, Daniel Aalto1; 1University of Alberta
Background. Neuroanatomical models of language processing have underscored the importance of the inferior frontal gyrus (IFG) and superior temporal gyrus (STG) in speech and reading processes; however, the contribution of these regions to overt vs. covert language processes is not well characterized. Distinguishing language processing for overt speech vs. covert speech is important for disambiguating speech planning versus brain activity related to motor commands. Here we explored brain activity via functional near infrared spectroscopy (fNIRS) from overt and covert tasks to better characterize the role of the IFG and STG under various task requirements. Methods. Young adult participants (N = 55) were presented with 380 letter strings that were randomly followed by a green square (say overtly) or red square (say silently). Standard preparation and preprocessing of the fNIRS data was applied using HOMER3 and included: 1) scalp coupling index, 2) downsampling, 3) intensity to optical density conversion, 4) artifact removal by channel and motion correction using a SplineSG, 5) removal of linear trends, 6) low bandpass filter, 7) optical density to concentration conversion, and 8) extraction of the averaged hemodynamic curve for the overt (green) and covert (red) trials. Results. We saw clear differences in the timing and magnitude of the peak of activity in the IFG and STG between overt and covert trials. Overt speech elicited stronger but relatively delayed activity peaks in both regions compared to covert speech (all p’s < 0.05). Conclusion. The IFG and STG are clearly involved in overt speech and silent reading processes, however there is a clear differentiation of brain activity of these regions between these tasks. Characterizing how these activity patterns differ is vital to theories of reading and speech production and will inform the development of brain computer interface technologies. The clear distinctions in these tasks identified with our approach can contribute to studies of speech/reading development and how these processes are compromised in disorder populations.
Topic Areas: Speech Motor Control, Language Production