Abstract
Schizophrenia is a heterogeneous disease. To cope with this heterogeneity, we tested a large sample of schizophrenia patients (n = 80), non-affected first-degree relatives (n = 56) and matched healthy controls (n = 52), in a visual backward masking (VBM) paradigm while recording the EEG. In VBM, a target stimulus is followed by a mask, which decreases performance on the target. We had three conditions: target only and two VBM conditions, with long and short inter-stimulus interval (ISI). Patients' performance was impaired, while the relatives performed at the same level as the controls. Performance was significantly correlated with the EEG N1 amplitude, as measured by the Global Field Power (GFP). Most interestingly, N1 amplitudes were higher in relatives compared to controls, while they were lower in patients relative to controls as previously reported. For relatives, N1 amplitudes were at the same level in all conditions; however, for controls and patients, N1 amplitudes increased with task difficult, e.g., amplitudes in the long ISI condition were lower than in short ISI condition. Our results suggest that relatives use a compensation mechanism tuning the brain to maximum performance in all conditions. Since relatives are already at the peak of their activations, increasing the task difficulty does not change brain processing.
Meeting abstract presented at VSS 2016