This paper reviews the literature on the Nl wave of the human auditory evoked potential. It concludes that at least six different cerebral processes can contribute to (he negative wave recorded from the scalp with a peak latency between 50 and 150 ms: a component generated in the auditory-cortex on the supratemporal plane, a component generated in the association cortex on the lateral aspect of the temporal and parietal cortex, a component generated in the motor and premotor cortices, the mismatch negativity, a temporal component of the processing negativity, and a frontal component of the processing negativity, The first three, which can be considered ‘true’ N1 components, are controlled by the physical and temporal aspects of the stimulus and by the general state of the subject. The other three components are not necessarily elicited by a stimulus but depend on the conditions in which the stimulus occurs. They often last much longer than the true N1 components that they overlap.

The N1 wave of the human electric and magnetic response to sound: a review and an analysis of the component structure

A deficit in inhibitory gating of auditory evoked responses was examined in 15 schizophrenic patients, their first-degree relatives, and normal subjects, using a conditioning-testing paradigm with the P50 wave of the auditory evoked response. This paradigm demonstrates inhibition by presenting paired stimuli to the subject; the P50 wave evoked by the second stimulus is reduced because of inhibitory mechanisms activated during the response to the first stimulus. In normal subjects, the mean amplitude of the second P50 response was reduced to less than 20%. In the schizophrenics, the mean amplitude of the second response was more than 85% of the first, a result that replicates our previous finding of a deficit in inhibition in schizophrenia. Approximately half the first-degree relatives, generally including at least one parent, had a similar deficit. Presence of this deficit in the parents was associated with a family history of schizophrenia. Family members with this deficit also had significantly higher scores on several scales of the Minnesota Multiphasic Personality Inventory than did family members without the deficit. Despite the deficit in inhibition, other characteristics of the P50 wave were normal in the relatives, in contrast to unmedicated schizophrenics, who showed additional abnormalities in wave latency and amplitude.

Deficits in Sensory Gating in Schizophrenic Patients and Their Relatives: Evidence Obtained With Auditory Evoked Responses

Twenty-one schizophrenics and 21 controls were exposed to a tenminute sequence of frequent and infrequent auditory stimuli. The amplitude of the third positive-going component (p 3 ) of the average evoked response to infrequent stimuli was much larger in the control group ( P 3 amplitude of 3.20μv in the first 2.5 minutes as a dividing point, only seven of the 42 subjects were misclassified. This amplitude had a significant correlation of -.48 with patient's age at first hospitalization. Amplitude of the second positive-going component (P 2 ) to frequent stimuli was also much larger in the control group (P

Some Features of the Auditory Evoked Response in Schizophrenics

http://pnl.bwh.harvard.edu/pub/pdfs/mccarley_1991SchizRes.pdf

Event-related potentials in schizophrenia: their biological and clinical correlates and new model of schizophrenic pathophysiology

• Several psychophysiological abnormalities associated with schizophrenia have been proposed as genetic trait markers of vulnerability to the disorder. Smooth pursuit eye tracking dysfunction and abnormal long latency eventrelated potentials are the most promising candidates. Both are independent of the effects of psychotropic medication or mental state at the time of testing, and twin studies demonstrate that each has a high level of heritability. Having recorded smooth pursuit eye tracking and event-related potentials in 20 high-density schizophrenic families, we find abnormalities in one or both measures in most of the families studied. The abnormalities, when present, occur in the family members with schizophrenia and other forms of functional psychosis, and they have a bimodal distribution with approximately half the nonschizophrenic relatives also showing eye tracking dysfunction and/or abnormal eventrelated potentials. Some of these relatives had psychiatric symptoms; others were normal. Our results suggest that psychophysiological examination can help to clarify the boundaries of schizophrenia spectrum disorder. By helping to decide the phenotypic status of nonschizophrenic family members, this should increase the power of DNA linkage studies.

https://jamanetwork.com/HttpHandlers/ArticlePdfHandler.ashx?journal=PSYCH&articleId=495525&pdfFileName=archpsyc_48_10_004.pdf

Auditory P300 and eye tracking dysfunction in schizophrenic pedigrees.

The authors investigated the clinical symptomatology, auditory evoked responses, and quantitatively analyzed EEGs of chronic schizophrenic patients with thought process disorder (TPD), schizophrenic patients without TPD, and matched normal volunteers. They describe the differences they found in terms of the variability, shape, latency, and amplitude of the patterns of the evoked potentials for the three groups. They also attempt to relate the neurophysiological findings with some characteristics of thought process disorder.

Auditory evoked response, EEG, and thought process in schizophrenics.

Changes in Somatosensory Evoked Potentials during Fluphenazine Treatment

Effect of Stimulatory Drugs on the Somatosensory Evoked Potential in Man

Somatosensory, visual and auditory evoked responses were studied in a left hemispherectomized patient. Median nerve stimulation and light flashes produced typical answers over only the unoperated hemi

B. Saletu

Papers

Auditory evoked response, EEG, and thought process in schizophrenics.

Changes in Somatosensory Evoked Potentials during Fluphenazine Treatment

Effect of Stimulatory Drugs on the Somatosensory Evoked Potential in Man

Evoked Responses After Hemispherectomy

Thiothixene in childhood psychoses.