PSYCHOPATHOLOGY FOR EARLY FRONTAL-LOBE DAMAGE - DEPENDENCE ON CYCLES OF DEVELOPMENT

A new theory of frontal lobe development is presented in which the rol e of the human frontal lobes during normal development and the psychop athological consequences of early frontal lobe injury are explored. An alyses of the development of human electroencephalograph (EEG) coheren ce indicate that there are oscillations and cyclic growth processes al ong the mediolateral and anterior-posterior planes of the brain. The c ycles of EEG coherence are interpreted as repetitive sequences of incr easing and decreasing synaptic effectiveness that reflects a convergen ce process that narrows the disparity between structure and function b y slowly sculpting and reshaping the brain's microanatomy. This proces s is modeled as a developmental spiral staircase in which brain struct ures are periodically revisited resulting in stepwise increases in dif ferentiation and integration. The frontal lobes play a crucial role be cause they are largely responsible for the selection and pruning of sy naptic contacts throughout the postnatal period. A mathematical model of cycles of synaptic effectiveness is presented in which the frontal lobes behave as gentle synaptic ''predators'' whereas posterior cortic al regions behave as synaptic ''prey'' in a periodic reorganization pr ocess. The psychopathological consequences of early frontal lobe damag e are discussed in the context of this model.