concept

generalized eigenvalue decomposition

Also known as: GED, generalized eigendecomposition

Facts (8)

Sources

Adversarial testing of global neuronal workspace and ... - Nature nature.com Nature Apr 30, 2025 7 facts

formulaThe Phase Locking Value (PPC) for a specific trial is calculated as the difference in phase angle between the MEG time series and iEEG electrode at each time t and frequency f, defined as: θj,k(f,t) = θ(f,t)e1 or GED filter - θ(f,t)e2 or GED filter.

procedureMEG cortical time-series analysis (N=65) extracted signals from cortical parcels in V1/V2, Prefrontal Cortex (PFC), and fusiform regions of interest, with category-selective signals obtained via a category-selective Generalized Eigenvalue Decomposition (GED) filter on fusiform activity.

referenceThe paper 'A tutorial on generalized eigendecomposition for denoising, contrast enhancement, and dimension reduction in multichannel electrophysiology' by Cohen, M. X. was published in NeuroImage, volume 247, 118809, in 2022.

measurementMEG DFC analysis of task-irrelevant trials without removing the evoked response reveals significant content-selective synchrony between the face-selective GED filter node and both V1/V2 and PFC regions, characterized by an increase in low-frequency connectivity (< 25 Hz) and a decrease in high-frequency connectivity (25–100 Hz).

procedureResearchers extracted a Generalized Eigenvalue Decomposition (GED) spatial filter for the Prefrontal Cortex (PFC) Region of Interest (ROI) using parcels from the Destrieux atlas to identify distributed source patterns responsive to visually presented stimuli.

measurementMEG PPC analysis of task-irrelevant trials with a sample size of 65 reveals significant category-selective synchrony below 25 Hz for face-selective GED filters in both V1/V2 and PFC regions of interest, and for object-selective synchrony in the PFC region of interest only.

procedureFor MEG analysis, category-selective single-trial time courses were extracted using the generalized eigenvalue decomposition (GED) method, where two GED spatial filters were built by contrasting faces or objects against all other categories during the first 0.5 s after stimulus onset.

11.4 Persuasive Strategies | Communication in the Real World courses.lumenlearning.com Lumen Learning 1 fact

measurementPrisoners who completed a GED reoffended at a rate 20 percent lower than the general prison population, while those who completed a college degree reoffended at a rate 44 percent lower than the general prison population.