Do behavioural and neurological asymmetries go hand in hand?

A dominant view in developmental neuropsychology is the "functionality through specialization and integration" hypothesis. Brain areas become more functionally specialized with age as the brain matures. Functionality is typically addressed in the context of communication between brain areas. As such it can be assessed by cortical connectivity analysis. In the context of motor control, the development of interhemispheric interactions between cortical motor areas within and across the midline remains largel y unexplored. We hypothesize that developmental changes in interhemispheric interactions are responsible for the progression of hand preference. Convincing evidence for a decoupling of motor areas is found in its possible behavioural correlate: as infants grow older, they tend to exhibit a shift in preferred movement from a bimanual mode to a unimanual mode. Moreover, the spatial and temporal coupling of the hands decreases from 7 to 11 months. Does learning to coordinate two hands amount to learning to i nhibit more precisely? To reveal the neuronal mechanisms behind these behavioural changes, we plan to perform a cross-sectional study with 7- and 11-month infants, using the non-invasive methods of electro-encephalography and electromyography. The tempora l and spatial aspects of the network involved will be assessed using decomposition methods combined with spectral analysis. The study of spontaneous activity in the brain at different time points along the early part of the human life span will contribute to our knowledge of how motor skills and properties of the human motor system are gradually developed and finally reach a mature form in the human brain. We can add here, that the scientific motivation has potentially important clinical ramifications. Si nce infant EEG is among the standard equipment of the modern hospital, prospects on the clinical use of our findings are promising.