Characteristics of Saccadic Responses in an Experimental “Go/No Go” Scheme in Healthy Subjects and Those at Ultra High Risk of Developing Schizophrenia

Abstract

Studies using presentation of visual stimuli in a “go/no go” scheme revealed differences in saccadic responses in healthy subjects and patients at ultra high risk of developing schizophrenia. Patients showed a greater number of erroneous responses to inhibitory stimuli and shorter latent periods (LP) for correct and erroneous saccades. Opposite asymmetries were demonstrated for the LP of saccadic responses in healthy subjects and patients: the LP of saccades to the right was shorter than to the left in healthy subjects, while the LP of saccades to the right was longer than to the left in patients. These data showed that impairments to the mechanisms controlling voluntary behavior occur at the pre-manifest stage of the course of schizophrenia when there is a ultra high risk of developing this condition. The results obtained here suggest that patients at ultra high risk of developing schizophrenia have impairments to the processes of voluntary and involuntary attention, as well as to the processes of inhibitory control, which may be due to dysfunction of the right prefrontal cortex and weakening of top down influences in the attention and inhibitory control systems.