Studying plasticity of sensory function: insight from pregnancy.

Plasticity of sensory function has become an object of study because of its proposed role in the recovery of function after central nervous system damage. Normal pregnancy may provide a useful in vivo model to study the effects of progressive reduction in the abdominal skin receptor density. As such changes are confined to abdominal skin, other parts of the body are only moderately affected by pregnancy and therefore can provide a control for other changes during pregnancy. The two-point discrimination test (TPDT) of the skin is a simple test of the sensory function. We conducted the TPDT in a pregnant population longitudinally studied at different pregnancy stages and in different skin regions. In this pregnant population, we found a reduction in sensory sensibility that was not skin region specific. In particular, the increase in abdominal circumference did not produce different effects of TPDT on the belly compared to the dorsum or the hand. This suggests that the sensory system is able to compensate for the reduction in peripheral information flow through central nervous system plasticity.