Non-Linear Connectivity and Intersubject Correlation Within the Visual Cortex During Movie and Rest
Poster No:
1451
Submission Type:
Abstract Submission
Authors:
Austin Cooper1, Amir Shmuel2, Janine Mendola2
Institutions:
1McGill University, Montréal, Quebec, 2McGill University, Montreal, Quebec
First Author:
Co-Author(s):
Introduction:
Naturalistic viewing (NV) functional MRI has emerged as a powerful tool for investigating the human brain's response to ecologically valid stimuli, providing insights into time-locked neural synchronization across individuals (Hasson et al., 2010; Vanderwal et al., 2017, 2019). Unlike resting-state (RS) paradigms, NV-fMRI captures intersubject correlation (ISC) patterns reflecting shared information processing in stimulus-driven conditions (Hasson et al., 2010). Meanwhile, mean functional connectivity (meanFC) metrics offer complementary insights by highlighting general connectivity strength. This study examines the alignment and divergence between ISC and meanFC metrics in the visual cortex during NV and RS paradigms, with a focus on variation across the eccentricity-based distribution.
Methods:
We analyzed data from the Human Connectome Project (7T) (Glasser et al., 2016; Van Essen et al., 2013), including 168 subjects with preprocessed NV- and RS-fMRI data. NV stimuli consisted of movie clips designed to engage the visual system broadly. Functional connectivity was assessed within eccentricity-defined ROIs using a retinotopic atlas (Benson et al., 2014). ISC was calculated as voxel-wise correlations across subjects, while meanFC was derived from within-subject Pearson correlations of ROI time series. Additionally, a signal-noise ratio analysis was performed for each individual in order to account for the potential that the findings may result from inhomogeneities in signal strength or effectiveness of atlas application within certain eccentricity representations.
Results:
ISC during NV was significantly higher across all visual cortex ROIs compared to RS, confirming enhanced neural synchronization under stimulus-driven conditions. The ISC exhibited an inverse U-shaped pattern across eccentricity bins, peaking at 5.56° during NV and 2.97° during RS. In NV, this peak was most pronounced in paracentral representations, whereas RS showed reduced and more foveal-dominant ISC peak. MeanFC also demonstrated a non-linear trend, peaking near 8° eccentricity during NV and RS, with NV displaying increases extending into peripheral visual regions compared to RS. Statistical analysis further revealed distinct ISC patterns between ROIs for both NV and RS, particularly between paracentral visual representations (2-10°) and both foveal and peripheral representations; though NV showed significantly broader statistical differences between ROIs.
·Line plot of relationship that mean functional connectivity and intersubject correlation across eccentricity values for both NV and RS, when using vertices across V1, V2, and V3.
Conclusions:
Our findings emphasize the nuanced interplay between ISC and meanFC metrics across NV and RS paradigms. The convergence of high ISC and meanFC in paracentral visual regions reflects robust, stimulus-driven synchrony under NV, where neural responses align most across individuals. In contrast, reduced ISC in foveal-dominant representations during RS and NV suggests idiosyncratic timeseries characteristics, likely resulting from their high spatial processing resolution.
Of major interest is the finding that RS displays a non-linear trend of ISC, with a distinct peak at 2.97°, which is unlike the flat distribution of ISC that would be expected. This peak of ISC in RS is lower than in NV, likely because increasing eccentricities are more heavily recruited in a shared manner whilst subjects watch movies, though the shared inverse U-shape trend between conditions is something which still needs to be replicated and understood.
Additionally, the broader NV-driven meanFC increases into peripheral regions highlight enhanced intra-subject connectivity, aligning with the visual cortex's role in integrating complex, naturalistic stimuli.
Of major interest is the finding that RS displays a non-linear trend of ISC, with a distinct peak at 2.97°, which is unlike the flat distribution of ISC that would be expected. This peak of ISC in RS is lower than in NV, likely because increasing eccentricities are more heavily recruited in a shared manner whilst subjects watch movies, though the shared inverse U-shape trend between conditions is something which still needs to be replicated and understood.
Additionally, the broader NV-driven meanFC increases into peripheral regions highlight enhanced intra-subject connectivity, aligning with the visual cortex's role in integrating complex, naturalistic stimuli.
Modeling and Analysis Methods:
fMRI Connectivity and Network Modeling 1
Perception, Attention and Motor Behavior:
Attention: Visual 2
Perception: Visual
Keywords:
FUNCTIONAL MRI
Vision
1|2Indicates the priority used for review
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Provide references using APA citation style.
Glasser, M. F., Smith, S. M., Marcus, D. S., Andersson, J. L. R., Auerbach, E. J., Behrens, T. E. J., Coalson, T. S., Harms, M. P., Jenkinson, M., Moeller, S., Robinson, E. C., Sotiropoulos, S. N., Xu, J., Yacoub, E., Ugurbil, K., & Van Essen, D. C. (2016). The Human Connectome Project’s neuroimaging approach. Nature Neuroscience 2016 19:9, 19(9), 1175–1187. https://doi.org/10.1038/nn.4361
Hasson, U., Malach, R., & Heeger, D. J. (2010). Reliability of cortical activity during natural stimulation. Trends in Cognitive Sciences, 14(1), 40. https://doi.org/10.1016/J.TICS.2009.10.011
Van Essen, D. C., Smith, S. M., Barch, D. M., Behrens, T. E. J., Yacoub, E., & Ugurbil, K. (2013). The WU-Minn Human Connectome Project: An overview. NeuroImage, 80, 62–79. https://doi.org/10.1016/j.neuroimage.2013.05.041
Vanderwal, T., Eilbott, J., & Castellanos, F. X. (2019). Movies in the magnet: Naturalistic paradigms in developmental functional neuroimaging. Developmental Cognitive Neuroscience, 36, 100600. https://doi.org/10.1016/J.DCN.2018.10.004
Vanderwal, T., Eilbott, J., Finn, E. S., Craddock, R. C., Turnbull, A., & Castellanos, F. X. (2017). Individual differences in functional connectivity during naturalistic viewing conditions. NeuroImage, 157, 521–530. https://doi.org/10.1016/J.NEUROIMAGE.2017.06.027