The Neurophysiological Features of Anticipation in Schizophrenia: A Cross-Sectional Study of Event-Related Potentials.

BACKGROUND

It is known that disorders of mental activity in schizophrenia patients may be caused by an impairment in the actualization of past experience during anticipation (prediction), which leads to impairment in constructing predictions, comparing incoming sensory information with the predictions, and updating the predictions. Previous studies have shown that the probability of an expected event affects the components of event-related potentials in mentally healthy individuals. However, it has not yet been studied how changes in the probability of an expected stimulus influence the behavior of individuals with schizophrenia and their event-related potential measures.

AIM

To compare the influence of event probability on the characteristics of brain potentials in patients with schizophrenia and healthy individuals.

METHODS

The study included mentally healthy individuals and male schizophrenia patients. Electroencephalograms were recorded while participants performed a saccadic task within the Central Cue Posner's Paradigm under conditions of varying probability (50% and 80%) of target stimulus presentation. Pre-stimulus (Contingent Negative Variation) and post-stimulus (Mismatch Negativity and P3) components of event-related potentials were analyzed upon the presentation of two types of target stimuli: standard (presented on the same side as the cue stimulus) and deviant (presented on the opposite side), under conditions of 50% and 80% stimulus congruence probability.

RESULTS

The study involved 20 mentally healthy individuals and 18 schizophrenia patients. In healthy subjects, the amplitude of the contingent negative variation increased with high stimulus congruence probability, while the amplitude of the Mismatch Negativity (MMN) and P3 component was higher for deviant stimuli under conditions of high (80%) probability. In schizophrenia patients, changes in probability demonstrated no impact on the amplitude of the contingent negative wave, MMN, or P3.

CONCLUSION

The characteristics of event-related potentials in patients with schizophrenia indicate impaired anticipation processes.