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Brain connectivity dimensions modulate language processing with modality-specific mechanisms.

Poster No:

1001

Submission Type:

Abstract Submission

Authors:

Lidon Marin-Marin¹^,2, Susanne Eisenhauer¹^,2, Elizabeth Jefferies¹^,2

Institutions:

¹University of York, York, United Kingdom, ²York Neuroimaging Centre, York, United Kingdom

First Author:

Lidon Marin-Marin
University of York|York Neuroimaging Centre
York, United Kingdom|York, United Kingdom

Co-Author(s):

Susanne Eisenhauer
University of York|York Neuroimaging Centre
York, United Kingdom|York, United Kingdom

Elizabeth Jefferies
University of York|York Neuroimaging Centre
York, United Kingdom|York, United Kingdom

E-Poster

Introduction:

Whole-brain patterns of functional connectivity are crucial for language processing. Decompositions of intrinsic connectivity have identified the dimensions of these patterns (called gradients) [Margulies et al., 2016]. The principal gradient represents the gradual shift from input-driven processes (sensory-motor) to more abstract ones (heteromodal). The second gradient represents the separation of visual from auditory and somatomotor regions. Finally, the third gradient describes a distinction between the default mode network and task-positive systems. The objective of our study was to investigate how these gradients influence brain activation during auditory and visual language processing, establishing whether these dimensions capturing the large-scale brain organisation of connectivity underlie similarities and differences across modalities.

Methods:

204 right-handed Dutch participants (100 males, mean age=22) in the MOUS ('Mother Of Unification Studies') dataset [Schoffelen et al., 2019] read or listened to sentences during fMRI. Data were pre-processed following a previous study analysing the visual task-fMRI data [Eisenhauer et al., 2023] using FSL. We used parameters of interest equivalent to those considered in that study to maintain results comparable between modalities: number of phonemes, phonological distance, word frequency, semantic similarity and position. GLMs in FSL were used to estimate the effects of each of the parameter on brain activation, averaged for 400 surface parcels [Schaefer et al., 2018]. Similarities between the visual and auditory maps were investigated by means of Pearson correlations using spin permutations to assess statistical significance and strength of correlations was compared. Each parameter's cortical map was related to the three gradients of connectivity using linear or quadratic models in R. The interaction between gradient and modality's effect on activation maps was also investigatedadding modality as an interaction term.

Results:

Brain activation maps of semantic similarity were significantly and positively correlated between visual and auditory modalities (r=0.34, pspin<.002), while word length (letters/phonemes) (r=-0.21, pspin=.038) and orthographic/phonological distance (r=-0.25, pspin<.016) were negatively correlated (Fig.1). The strength of semantic similarity's correlation was significantly higher than the other two (z=6.41, p<.001; z=6.88, p<.001). We found a statistically significant interaction between the principal gradient and modality on brain activation maps in the following parameter pairs: word length (letters/phonemes) (pspin<.002) and orthographic/phonological distance (pspin<.002; Fig.2). The second gradient interacted significantly with modality in semantic similarity (pspin<.002) and orthographic/phonological distance (pspin=.018; Fig.2). Finally, we found a significant interaction between the third gradient and modality on word frequency (pspin<.002), and word length (pspin<.002; Fig.2).

·Figure 1. Visual and auditory activation maps of parameters of interest and significant correlations (spin permutation-corrected) between modalities. (High-res image available upon request)

·Figure 2. Gradient maps, relationships between activation maps of parameters of interest and gradients, and significant interactions between gradient and modality. (High-res available upon request).

Conclusions:

Brain activation for semantic similarity was positively correlated between visual and auditory modalities, while visual/auditory variables showed a negative correlation between maps, and more differences in their relationship to gradients across modalities. This supports the idea of processing dissociation for sensory input and integration for more abstract representations. Differences between modalities in visual/auditory variables also relate to previous behavioural studies [Eisenhauer et al., 2023, Suárez et al., 2011, Baddeley et al., 1975; Jefferies et al., 2011], suggesting divergent difficulty mechanisms. In sum, the different effects of semantic, lexical and input-level linguistic variables are captured by connectivity gradients. All dimensions of connectivity exhibit different relationships to language processing depending on modality, which could be related to the transient nature of auditory processing, as compared to visual processing, more explicit and transparent.

Language:

Language Comprehension and Semantics ¹

Reading and Writing

Speech Perception

Modeling and Analysis Methods:

Activation (eg. BOLD task-fMRI) ²

Connectivity (eg. functional, effective, structural)

Keywords:

FUNCTIONAL MRI

Language

Other - listening, reading, brain connectivity

^1|2Indicates the priority used for review

Provide references using author date format

Baddeley AD, Thomson N, Buchanan M (1975): Word length and the structure of short-term memory. Journal of Verbal Learning and Verbal Behavior 14:575–589.
Eisenhauer S, Alam TR del JG, Cornelissen PL, Smallwood J, Jefferies E (2023): Individual word representations dissociate from linguistic context along a cortical unimodal to heteromodal gradient. bioRxiv:2023.04.25.538257.
Jefferies E, Frankish C, Noble K (2011): Strong and long: Effects of word length on phonological binding in verbal short-term memory. Quarterly Journal of Experimental Psychology 64:241–260.
Margulies DS, Ghosh SS, Goulas A, Falkiewicz M, Huntenburg JM, Langs G, Bezgin G, Eickhoff SB, Castellanos FX, Petrides M, Jefferies E, Smallwood J (2016): Situating the default-mode network along a principal gradient of macroscale cortical organization. Proceedings of the National Academy of Sciences of the United States of America 113:12574–12579.
Schaefer A, Kong R, Gordon EM, Laumann TO, Zuo X-N, Holmes AJ, Eickhoff SB, Yeo BTT (2018): Local-Global Parcellation of the Human Cerebral Cortex from Intrinsic Functional Connectivity MRI. Cerebral Cortex (New York, NY) 28:3095.
Schoffelen JM, Oostenveld R, Lam NHL, Uddén J, Hultén A, Hagoort P (2019): A 204-subject multimodal neuroimaging dataset to study language processing. Scientific Data 2019 6:1 6:1–13.
Suárez L, Tan SH, Yap MJ, Goh WD (2011): Observing neighborhood effects without neighbors. Psychonomic Bulletin and Review 18:605–611.