Movement-related brain macropotentials during skilled performances. A developmental study.

A developmental study of movement-related brain macropotentials (MRBMs) during a self-paced bimanual skilled performance task (Papakostopoulos 1980) was carried out. MRBMs were obtained from Fpz, Cz and right and left pre-central and electromyograms were recorded from the left and right flexor muscles of the forearms in 30 normal children ranging from 8 to 13 years of age. A consistent Bereitschaftspotential appeared in children of 10 years; in the younger children it was absent or it was positive at precentral and central locations. The motor cortex potential and P200 were present in all children. The skilled performance positivity (SPP), absent at 8 and 9 years, appeared at 11 years of age and was present in older children. The latency of P200 and SPP decreased with age. ANOVA tests showed a statistically significant age effect on performance, EMG rise time and MRBMs; MRBMs were not statistically influenced by time in the experiment: MCP and P200 increased in amplitude with improvement of performance. The results indicate different rates of maturation of the neuronal systems underlying the genesis of the various movement-related brain macropotentials.