Study of Defect Scattering in the Pseudogap State of $Bi_2Sr_2CaCu_2O_{8+\delta}$*

The pseudogap state in high-Tc superconductors continues to be one of the most puzzling aspects of these materials. The local response of this unusual electronic state to defects can potentially teach us about its underlying electronic correlations. Using a home-built scanning tunneling microscope (STM) we have performed spatially resolved measurements of the density of states in Ni and Zn doped Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$ samples in the pseudogap state above Tc. We will present these measurements and compare them to similar studies in the superconducting state.