A US Congresswoman seriously injured in a shooting spree wished her husband and brother-in-law a happy birthday – and also thanked the Houston hospital where she is undergoing intensive rehabilitation for a cake that featured the likeness of her astronaut husband.

A US congresswoman shot in the head two weeks ago is moving to a Houston rehab centre today where her husband hopes she will continue on the path to a full recovery.

Congresswoman Gabrielle Giffords remained heavily sedated and in a critical condition today as investigators sought to understand what motivated a gunman to carry out the assassination attempt in a rampage that left six people dead.