Inhibitory Deficits in Prepulse Inhibition, Sensory Gating, and Antisaccade Eye Movement in Schizotypy

Schizotypy is a term that refers to a continuum of personality characteristics, emerging from mental states ranging from organized and normal to unorganized and disordered; with the latter tending to include individuals with high schizotypal scores as well as those diagnosed with schizotypal personality disorder. Evidence from psychophysiological studies has found a relative weakness in the inhibitory functioning, including prepulse inhibition (PPI), sensory gating (SG), and antisaccade eye movement (AEM) in schizotypy and schizophrenia. As schizotypy and schizophrenia are in the same spectrum, understanding the nature of sensory and motor inhibitory weakness associated with schizotypy will optimize the prevention and intervention for both schizotypy and schizophrenia populations. This review aims at examining the deficits of sensory gating, saccade control, and prepulse inhibition in schizotypy; examining the relationship between the three measures and schizotypal symptoms and traits; examining the effect of nicotine on the three measures; and examining the relevant brain regions to the three measures. We searched multiple databases (such as MEDLINE, Pubmed, PsychINFO, Google Scholar) using combinations of the keywords: schizotypy, schizotypal personality disorder, prepulse inhibition, sensory gating and antisaccade for articles published in English since 1980. We found that three measures (SG, PPI and AEM) are associated with major schizotypal symptoms, suggesting that three measures could be used to predict the disease etiology and prognosis. Secondly, the three measures are modulated by nicotine administration at a certain level, providing a potential tool to study the role of nicotine in the cognition and symptom improvement in schizotypy. Thirdly, brain-imaging studies have localized activity in brain regions associated with sensory gating, saccade control, and prepulse inhibition, narrowing the search for brain regions to target for the treatment and prevention of schizotypy. Overall, the three measures are suggested to be a valuable tool to study the inhibitory deficits in schizotypy, and maybe used as a tool for the prevention and treatment of schizotypy as well.