A powerful metric for expressive language lateralization in MEG

Magnetoencephalography (MEG) has proven valuable for presurgical language lateralization. Investigators have established that low-beta (13-23 Hz) event-related desynchrony (ERD), a neuromagnetic signature for increased neuronal firing, maps to critical language centers for expressive language tasks in MEG. The distribution of low-beta ERD is relatively bilateral in early childhood, transitioning to left lateralized by adolescence or early adulthood. Recently, we showed that a comple-mentary signal, low-beta event-related synchrony, thought to reflect neuronal inhibition, becomes increasingly right lateralized across development. Here, we introduce a hybrid laterality index for language derived from both low-beta ERD and ERS. We present findings from a large cohort of children performing verb generation in MEG, and show that inclusion of low-beta ERS provides relatively powerful estimation of language lateralization.