Gating of auditory response in schizophrenics and normal controls. Effects of recording site and stimulation interval on the P50 wave.
ABSTRACT Auditory evoked potentials were recorded using a paired stimulus, conditioning-testing paradigm from 14 schizophrenic patients and 13 normal subjects with no family history of psychotic disorder. Previous studies of the vertex P50 wave using this paradigm have demonstrated a possible sensory gating deficit in schizophrenics, as shown by their failure to diminish the response to a test stimulus presented 500 ms after a conditioning stimulus. Recordings were made at Cz, Fz, C3, T3, C4, and T4, to compare effects at different recording sites with this paradigm. Schizophrenics had significantly poorer sensory gating than normals, with the most significant difference between the groups at Cz. In addition to the 500 ms interval, subjects were also recorded at a conditioning-testing interval of 100 ms. Most schizophrenics showed normal sensory gating at the 100 ms interval, despite their abnormalities at 500 ms. The results indicate that Cz is optimal recording site for this paradigm, and that gating abnormalities in schizophrenic subjects are limited to specific interstimulus intervals.
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ABSTRACT: Patients with schizophrenia exhibit disturbances in information processing. These disturbances can be investigated with different paradigms of auditory event related potentials (ERP), such as sensory gating in a double click paradigm (P50 suppression) and the mismatch negativity (MMN) component in an auditory oddball paradigm. The aim of the current study was to test if rats subjected to social isolation, which is believed to induce some changes that mimic features of schizophrenia, displays alterations in sensory gating and MMN-like response. Male Lister-Hooded rats were separated into two groups; one group socially isolated (SI) for 8 weeks and one group housed (GH). Both groups were then tested in a double click sensory gating paradigm and an auditory oddball paradigm (MMN-like) paradigm. It was observed that the SI animals showed reduced sensory gating of the cortical N1 amplitude. Furthermore, the SI animals showed significant reduction in cortical MMN-like response compared with the GH animals. No deficits in sensory gating or MMN-like response were observed in the hippocampus (CA3) of the SI animals compared with GH animals. In conclusion, the change in sensory gating of the N1 amplitude supports previous findings in SI rats and the reduced MMN-like response is similar to the deficits of MMN seen in patients with schizophrenia. Since reduced auditory MMN amplitude is believed to be more selectively associated with schizophrenia than other measures of sensory gating deficits, the current study supports the face validity of the SI reared rat model for schizophrenia.Behavioural brain research 03/2014; · 3.22 Impact Factor
Article: P50 sensory gating in infants.[Show abstract] [Hide abstract]
ABSTRACT: Attentional deficits are common in a variety of neuropsychiatric disorders including attention deficit-hyperactivity disorder, autism, bipolar mood disorder, and schizophrenia. There has been increasing interest in the neurodevelopmental components of these attentional deficits; neurodevelopmental meaning that while the deficits become clinically prominent in childhood or adulthood, the deficits are the results of problems in brain development that begin in infancy or even prenatally. Despite this interest, there are few methods for assessing attention very early in infancy. This report focuses on one method, infant auditory P50 sensory gating. Attention has several components. One of the earliest components of attention, termed sensory gating, allows the brain to tune out repetitive, noninformative sensory information. Auditory P50 sensory gating refers to one task designed to measure sensory gating using changes in EEG. When identical auditory stimuli are presented 500 ms apart, the evoked response (change in the EEG associated with the processing of the click) to the second stimulus is generally reduced relative to the response to the first stimulus (i.e. the response is "gated"). When response to the second stimulus is not reduced, this is considered a poor sensory gating, is reflective of impaired cerebral inhibition, and is correlated with attentional deficits. Because the auditory P50 sensory gating task is passive, it is of potential utility in the study of young infants and may provide a window into the developmental time course of attentional deficits in a variety of neuropsychiatric disorders. The goal of this presentation is to describe the methodology for assessing infant auditory P50 sensory gating, a methodology adapted from those used in studies of adult populations.Journal of Visualized Experiments 01/2013;
Article: Animal models of schizophrenia[Show abstract] [Hide abstract]
ABSTRACT: Schizophrenia is a complex disorder affecting all domains of human life. Distinction is made between positive (delusions, hallucinations), negative (blunted affect, avolition, social withdrawal), cognitive (attention, executive function, thought disorder) and affective symptoms (anxiety, depression). The vulnerability-stress model is generally used to describe the evolution of the disorder over time and to guide psychosocial and pharmacological treatment. The biological vulnerability to stress is determined by the interaction of genetic and environmental influences. A neuro-developmental model is used to explain the observed structural and functional abnormalities in the brain of schizophrenic patients.In the past most animal models for schizophrenia have been used to develop new medication and to explain the mode of action of antipsychotic drugs. However, in recent years more attention has focused on developing models which may be more related to the schizophrenic (psycho)pathology. The new generation of animal models focus predominantly on mimicking the neurodevelopmental hypothesis of schizophrenia, by manipulating rats in a very early stage of life, and studying the long term consequences. These manipulations include early lesions or maternal deprivation.Neuroscience Research Communications 05/2000; 26(3).