To the Editor: We thank Dr. Kéri et al. for their kind comments regarding our article. While the issue of the effects of antipsychotic medication is important, it is unlikely to account for our finding of magnocellular dysfunction in schizophrenia. As cited by Dr. Kéri et al. (Masson et al., 1993), evidence suggests that dopamine may play a role in processing low-spatial, high-temporal frequency stimuli, which are thought to elicit predominantly magnocellular responses. However, the role of dopamine may be to decrease response under these spatiotemporal conditions (1). Thus, blockade of dopamine receptors may in fact increase response under these conditions (1). In addition, in previous visual backward-masking studies (2, 3), we did not find a difference in performance in patients who were tested while they were and were not taking medication. This finding is in agreement with the results of other studies, showing that antipsychotic medications do not appear to cause this deficit (e.g., reference 4).