Subregional dynamics in the insula capture its diverse functional connectome topographies
Poster No:
2126
Submission Type:
Abstract Submission
Authors:
Jessica Royer1, Donna Gift Cabalo2, Raúl Rodríguez-Cruces2, Ella Sahlas2, Casey Paquola3, Sofie Valk4, Birgit Frauscher5, Boris Bernhardt2
Institutions:
1McGill University, Montreal, QC, 2McGill University, Montreal, Quebec, 32Institute for Neuroscience and Medicine, INM-7, Forschungszentrum Jülich, Jülich, North Rhine-Westphalia, 4Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Saxony, 5Duke University School of Medicine, Durhan, NC
First Author:
Co-Author(s):
Casey Paquola
2Institute for Neuroscience and Medicine, INM-7, Forschungszentrum Jülich
Jülich, North Rhine-Westphalia
2Institute for Neuroscience and Medicine, INM-7, Forschungszentrum Jülich
Jülich, North Rhine-Westphalia
Introduction:
The insula is involved in diverse sensory, visceral, cognitive, and socio-affective functions [1-3] supported by intricate connectivity patterns [4-6] and microanatomical properties [7,8]. While invasive electrical stimulation studies and functional neuroimaging suggest convergent functional organization in this region, it remains unclear how the insula's resting subregional dynamics relate to its connectivity profiles. The present work explores this question by cross-referencing neurophysiological data with ultra-high field MRI to track insular function with unprecedented spatiotemporal precision.
Methods:
The MNI open iEEG atlas [9] provides iEEG recordings acquired during conditions of resting wakefulness in 106 patients with intractable epilepsy (Fig1A). By excluding channels involved in ictal and inter-ictal activity, this dataset provides a putative reference space for normal human neurophysiology. Data pre-processing included band-pass filtering (0.5-80Hz), downsampling (200Hz), and demeaning. We first computed the band power (delta [δ]: 0.5-4Hz; theta [θ]: 4-8Hz; alpha [α]: 8-13Hz; beta [β]: 13-30Hz; gamma [γ]: 30-80Hz) of each channel. The spatial coverage of each channel was expanded by 5mm along the cortical surface ("channel region"), resulting in complete coverage of the insula delineated by labels of the aparc parcellation [10]. For each channel, band power values were normalized so their total would equal one. Normalized band power was computed at each vertex by averaging corresponding values of overlapping channel regions (Fig1B). Resulting normalized band power maps were then cross-referenced with resting-state functional MRI (rs-fMRI) data of participants scanned using 7 Tesla MRI and included in the MICA-PNI dataset (n=10, 3 sessions each; 4/6 M/F, age=26.6±4.6 years) [11] and decoded across established functional network communities [12]. Functional timeseries were smoothed along the cortical surface (FWHM=5mm), and sessions were concatenated for each participant. Mixed effects models were implemented via BrainStat13 and findings were corrected for multiple comparisons using random field theory.
·Figure 1
Results:
The insular cortex showed diverse neurophysiological properties (Fig1B). We observed prominent delta band activity in ventral anterior and middle subregions. Theta and alpha band activity were highest in posterior regions, while beta power was relatively elevated across large portions of the mid- and anterior insula. High gamma-range activity was present in dorsal anterior and posterior subregions. Thresholded normalized band power maps (top 15%) were used to define bilateral, homologous seeds to map subregional functional connectivity constrained by local iEEG dynamics. Functional connectivity analyses leveraging rs-fMRI showed that subregional physiology reflects the insula's broad network embedding. This approach showed variable connectivity profiles to somatomotor, dorsal attention, salience, and frontoparietal networks (Fig2A), consistent with prior functional imaging studies. Benchmarking connectivity profiles of neurophysiological seeds against those of the whole insula showed significantly enhanced connectivity of delta and gamma subregions with mesiotemporal and anterior cingulate cortices, respectively. Theta and alpha band seeds were associated with higher connectivity to pre- and postcentral gyri, while beta-dominant subregions displayed stronger frontoparietal connectivity (Fig2B; all pFWE<0.01).
·Figure 2
Conclusions:
These findings demonstrate that the insula's neurophysiological properties are closely associated with its subregional functional connectivity and neurocognitive specialization. The observed coupling between specific frequency bands and distinct large-scale networks provides novel insights into the insula's functional organization. This work underscores the utility of integrating invasive electrophysiology with ultra-high field MRI to decode fine-grained brain dynamics.
Modeling and Analysis Methods:
Connectivity (eg. functional, effective, structural)
fMRI Connectivity and Network Modeling 2
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Anatomy and Functional Systems
Physiology, Metabolism and Neurotransmission:
Physiology, Metabolism and Neurotransmission Other 1
Keywords:
ADULTS
Cortex
Electroencephaolography (EEG)
ELECTROPHYSIOLOGY
FUNCTIONAL MRI
Systems
1|2Indicates the priority used for review
Abstract Information
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Provide references using APA citation style.
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