Characterize laminar-specific interhemispheric functional coherence in resting-state fMRI using bilateral line-scanning fMRI (BiLS)
Sangcheon Choi1,2, Yi Chen1, Hang Zeng1,2, and Xin Yu1,3
1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2Graduate Training Centre of Neuroscience, Tuebingen, Germany, 3MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, United States
We developed a bilateral line-scanning (BiLS) fMRI method to investigate interhemispheric slow fluctuations (< 0.1 Hz) with laminar specificity in rs-fMRI in anesthetized rats. Based on the coherence analysis, two distinct slow fluctuation features in symmetric cortices were identified.
Fig. 1. BiLS acquisition in resting-state fMRI. A) Sequential signal processing of the conventional UniLS method. B) Spatiotemporal map and percentage change map in evoked fMRI using the UniLS method. C-F) resting-state BOLD responses in the symmetric FP-S1 regions using BiLS method (n = 32 trials of 4 rats). C) Top: Representative Z-normalized fMRI time series. Bottom: normalized cortical depth maps in both the FP-S1 regions from one representative trial. D-E) Comparison of the filtered time series (D) and their PSDs from the same trial (E). F) PSDs from another representative trial.
Fig. 2. Laminar-specific coherence in rs-fMRI. A) Laminar-specific coherence (n = 32 trials of 4 rats) showing that L2/3 is significantly different at 0.08-0.1 Hz (one-way ANOVA, post-hoc: *p-value <0.05, Bonferroni correction). B) K-means clustering based grouping with L2/3 specific coherence values at 0.01-0.02 Hz (x-axis) and 0.08-0.1 Hz (y-axis). C) Independent group t-test with the L2/3 coherence values from the individual groups at 0.01-0.02 Hz (left) and 0.08-0.1 Hz (right), showing significant difference at 0.08-0.1 Hz (**p-value = 1.4127*10^-10).