[Synaptic reorganization in early childhood experience and learning processes: relevance for the development of psychological diseases].

This article presents a neurobiological hypothesis of experience- and learning dependent synaptic reorganization processes in the juvenile brain and their influence on the normal development of intellectual, emotional and social abilities. Based on experimental data we offer the theory that during early learning events (also termed as imprinting) the initially relatively unspecifically organized synaptic network in the higher associative brain areas undergoes an experience- and learning-dependent reorganization. This process involves synaptic sprouting as well as synaptic pruning of redundant synaptic connections and results in a more specific and efficient neuronal network, which provide the basis for learning processes during later life. Sensory or social deprivation during early childhood impairs this synaptic reorganization of the brain and thereby prevents the normal development of intellectual, emotional and social abilities. Under adverse environmental and familial circumstances these deficits may eventually lead to mental disorders such as neuroses. Since early learning and the underlying synaptic reorganization processes are restricted to specific sensitive phases during brain development the resulting mental and social deficits are remarkably stable, which may be one explanation of the resistance of certain mental disorders to psychotherapy. The intention of this provocative hypothesis is to stimulate future research initiatives using an interactive neurobiological and neuropsychological approach to gain more insight into these cellular mechanisms and to develop innovative therapeutical strategies.