Atypical temporal activation pattern and central-right brain compensation during semantic judgment task in children with early left brain damage

In this study we investigated the event-related potentials (ERPs) during the semantic judgment task (deciding if the two Chinese characters were semantically related or unrelated) to identify the timing of neural activation in children with early left brain damage (ELBD). The results demonstrated that compared with the controls, children with ELBD had (1) competitive accuracy and reaction time in the semantic judgment task, (2) weak operation of the N400, (3) stronger, earlier and later compensational positivities (referred to the enhanced P200, P250, and P600 amplitudes) in the central and right region of the brain to successfully engage in semantic judgment. Our preliminary findings indicate that temporally postlesional reorganization is in accordance with the proposed right-hemispheric organization of speech after early left-sided brain lesion. During semantic processing, the orthography has a greater effect on the children with ELBD, and a later semantic reanalysis (P600) is required due to the less efficient N400 at the former stage for semantic integration.

The development of semantic priming effect in childhood: an event-related potential study

To investigate the development of semantic priming effect in school children, we examined the event-related potentials in 120 children from 7 to 12 years when they were instructed to perform a lexical decision task. The well-known N400 component and a late positive component showed parabolic changes with the age growing. In addition, the lateralization of the brain potentials indicated the early stage in elementary school was the curial time for development of linguistic neural networks. This finding first revealed the detailed changes of semantic priming effect in childhood.