Somatosensory processing in healthy newborns

Attempting to understand more about somatosensory processing in newborns, we give an overview of somatosensory potential studies in preterm and term healthy newborns conducted during the past few decades. In addition, we present some of our recent data from somatosensory studies conducted with magnetoencephalography (MEG). The reviewed studies show maturational patterns of cortical responses to median and tibial nerve stimulation within the preterm-term period. In this era, maturation is reflected mainly as shortening of the latencies and increase in the amplitude of especially the early responses. However, the actual somatosensory processing beyond the latency and amplitude analysis has not been the goal in these studies. Although the somatosensory pathways and cortex are mature enough to produce the evoked responses, difficulties in measuring the neonatal responses with similar parameters as used for adults is suggested to reflect the special characteristics of newborn processing. Possible factors behind the inconsistencies between different newborn studies are discussed.