[The indices of EEG spatial synchronization in normal 10- to 12-year-old schoolchildren and in learning difficulties]

10-12-year-old schoolchildren were divided into three groups: a normal one, a group with psychological problems, and a third one with medical problems. The EEG was recorded at resting and while reading a text. An obviously higher global spatial synchronisation was found in the normal group as compared with the "medical" one. In the "psychological" group, a diffuse hyperresponsiveness was found in the transition state from resting to activity. The above differences seem to be due to a morpho-functional immaturity and a functional insufficiency of two different portions of the brain ascending activating system. Evidently the "medical" group children have an immaturity of the bulbar and midbrain reticular formation, whereas the "psychological" group children have, probably, an immature diencephalic activating system (the thalamus).