We present adaptive optics assisted spectroscopy of three quasars obtained with NACO at VLT .
The high angular resolution achieved with the adaptive optics ( \sim 0.08 ^ { \prime \prime } ) , joined to the diagnostic power of near-IR spectroscopy , allow us to investigate the properties of the innermost 100 pc of these quasars .
In the quasar with the best adaptive optics correction , PG1126 - 041 , we spatially resolve the Pa \alpha emission within the nuclear 100 pc .
The comparison with higher excitation lines suggests that the narrow Pa \alpha emission is due to nuclear star formation .
The inferred intensity of the nuclear star formation ( 13 M _ { \odot } ~ { } yr ^ { -1 } ) may account for most of the far-IR luminosity observed in this quasar .