The startle reflex in schizophrenia research

Abnormalities of attention and information processing are described as impo rtant features of schizophrenia. Theoretically, they may reflect deficienci es in central mechanisms of inhibition and selection. These deficiencies ar e believed to lead to cognitive fragmentation in patients with schizophreni a. Findings of an impaired prepulse-inhibition (PPI) and habituation of the startle reflex in patients with schizophrenia are thought to represent pre attentive, i.e., automatic attention deficits. Other paradigms with attenti onal instructions help to detect and to quantify deficits in controlled att entional functions. The PPI of the auditory startle blink reflex - mediated primarily by brainstem structures - is regulated by cortico-striato-pallid o-pontine influences and by neurotransmitters involved in the pathogenesis of schizophrenia. An animal model of PPI provides the possibility to test n eurobiological hypotheses in schizophrenia and to screen substances for the ir potential antipsychotic properties. Because reduction of PPI also occurs in other neuropsychiatric disorders,further studies are required to develo p new paradigms of startle modification with findings of higher specificity and probable diagnostic relevance in patients with schizophrenia.