The present study had three primary aims. The first aim was to investigate the existence and extent of IHTT abnormalities to unilaterally-presented visual stimuli in patients with schizophrenia with a more rigorous methodology than has been employed previously, including using a dense electrode array, calculating IHTTs from multiple electrode pairs, and using Current-Source Density (CSD) transformed data. CSD (Perrin et al., 1987) is an improvement over using traditional voltage ERP measurements for estimating IHTT because it attenuates the effects of volume conduction and acts as a high-pass spatial filter, thus reducing the overlap between ERPs at contra- and ipsilateral electrode sites (Saron et al., 2003). Also, CSD is reference-independent, meaning that the waveforms at different electrodes are not influenced by activity at a common reference electrode.
