Structural templates for imaging EEG cortical sources in infants

Abstract

Electroencephalographic (EEG) source reconstruction is a powerful approach that allows anatomical localization of electrophysiological brain activity. Algorithms used to estimate cortical sources require an anatomical model of the head and the brain, generally reconstructed using magnetic resonance imaging (MRI). When such scans are unavailable, a population average can be used for adults, but no average surface template is available for cortical source imaging in infants. To address this issue, we introduce a new series of 13 anatomical models for subjects between zero and 24 months of age. These templates are built from MRI averages and boundary element method (BEM) segmentation of head tissues available as part of the Neurodevelopmental MRI Database. Surfaces separating the pia mater, the gray matter, and the white matter were estimated using the Infant FreeSurfer pipeline. The surface of the skin as well as the outer and inner skull surfaces were extracted using a cube marching algorithm followed by Laplacian smoothing and mesh decimation. We post-processed these meshes to correct topological errors and ensure watertight meshes. Source reconstruction with these templates is demonstrated and validated using 100 high-density EEG recordings from 7-month-old infants. Hopefully, these templates will support future studies on EEG-based neuroimaging and functional connectivity in healthy infants as well as in clinical pediatric populations.

Does participant’s age impact on tDCS induced fields? Insights from computational simulations

“…Our results specifically revealed GM volume linearly decreased, whilst WM remained relatively stable with age, with slight decrease for the youngest and eldest atlases. This is comparable to previous research, where GM generally decreased with age, falling within 0.4-0.9L [62][63][64][65][66][67][68][69][70][71], whilst WM displays a 'bell-shaped' curve, ranging between 0.3-0.7 L [62][63][64]66] and 'peaking' within the fourth decade [64,66]. Moreover, CSF volume within our atlases was revealed to increase with age for which there is a multitude of support from the literature, where volumes have been reported to vary between 0.2-0.6 L [64,67,69].…”

An Observational Investigation of Spatiotemporally Contiguous Heatwaves in China From a 3D Perspective

“…org/project/connected-components-3d/). The CC3D method has been used to segment different cells or organs (e.g., kidneys and tumors) in medical studies (O'Reilly et al, 2021;Park et al, 2021;Zhao et al, 2020), and it also demonstrates potential in identifying connected events in climatological research (Reddy et al, 2021). The procedure of the method is briefly introduced as follows by starting with 2D CCL.…”

Infant brain imaging using magnetoencephalography: Challenges, solutions, and best practices

“…When individual anatomical MRIs are available for infant participants, the co‐registration process is much the same for infants as for adults. However, in addition to being expensive, individual MRIs for infants are typically much more difficult to obtain, so we recommend using suitable age‐matched templates from O'Reilly, Larson, Richards, and Elsabbagh ( 2021 ), as they overcome many typical issues with infant source modeling (e.g., lack of surface and volumetric anatomical labels). Surfaces from anatomical templates should be warped to match the participant's head digitization.…”