Laminar layer 7T fMRI-EEG reveals human alpha oscillations are predominately from superficial and deep layers

Abstract

EEG alpha (8-13Hz) oscillations occur throughout the cortex but the generating mechanisms are poorly understood. Opinion is divided between alpha being driven by bottom-up, top-down or both of these processes. Using simultaneous 7T-fMRI-EEG with an eyes open/closed paradigm, we assess the generator of alpha by performing layer-fMRI analysis of GE-BOLD data to determine the strongest BOLD-alpha negative layer correlations. We show that, after accounting for draining vein effects using spatial deconvolution, alpha-BOLD correlations are strongest in the superficial and deep layers suggesting they are predominately driven by top-down processes.

LayNii: A software suite for layer-fMRI

“…It’s Github site welcomes >1400 unique visitors per year and its code is being cloned >100 times per month. It found particular application for layer-fMRI studies in the motor cortex ( Huber et al 2017 ), in sensory cortex ( Yu et al 2019 ), DLPFC ( Finn et al 2019 ), across association cortices ( Finn et al, 2020 ) for columnar imaging in the motor cortex ( Huber et al 2020b ), in layer-specific functional connectivity mapping ( Huber et al 2020a ), for mental imaginary layer-fMRI ( Persichetti et al 2020 ), for methods development of new sequences ( Beckett et al 2020 ; Chai et al 2019 ; Guidi et al 2020 ), for visual layer-fMRI ( Zamboni et al 2020 ), for model-based removal of vein effects in layer-fMRI-EEG ( Marsh et al 2020 ) and for methods debugging of human 9.4T layer-fMRI ( Huber et al 2018 ). In the early days of LayNii, its programs were shaped and optimized by continuous interactions with its users.…”