Figure 2.

A vernier was followed by a variety of gratings (the vernier is not shown, only the masking gratings). (A) Because we used for each observer his/her individual vernier duration and ISI, performance is roughly the same in patients and controls when the 25 element grating follows the vernier. Performance deteriorates significantly for the patients and healthy controls if either a “gap grating” or a “5–25” element grating follows the vernier. In the 5–25 grating, a 5 element grating is presented for 20 ms followed immediately by a 25 element grating for 280 ms. Because of the short duration, the 5 element grating is invisible. Performance deficits are similar in patients and controls indicating, paradoxically, intact spatial and temporal processing of the schizophrenic patients, i.e., patients seem to process the gaps and the briefly presented 5 element grating “carefully.” Were the gaps fully blurred or the 20 ms 5 element grating smeared out, performance would be on the level of the homogeneous 25 element grating (#25). However, this is not the case. (B) (a) As in (A), performance of patients and controls is roughly identical with the homogenous 25 element grating because we used the individual vernier durations and ISIs. (b) Performance strongly deteriorates by adding single collinear lines. (c) Horizontal contextual lines yield a performance level comparable to the standard condition (a). (c) Combining vertical and horizontal lines from the conditions (b) and (c) improves performance compared to (b). The horizontal contextual lines “counteract” the vertical lines. Again, it seems that patients “carefully” process the task irrelevant vertical lines, reflected in the strong performance deficits. This deterioration and the recovery from it by horizontal lines, is very similar to the one of controls. Reprinted with permission from Herzog et al. (2004) and Roinishvili et al. (2008).