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Biomedical subjects

A S Bernstein

Publications and source records attributed to A S Bernstein.

23 records · Page 2Linked to original sources
PubMedDate not supplied

The orienting response and stimulus significance: further comments.

Siddle's (1979) assertion that the significance hypothesis is based on tautological argument regarding the effects of intensity decrease refer only to two papers which first suggested the need for research into determinants other than mismatch. Studies testing specific predictions followed in various laboratories, and it is their results that support the hypothesis. The hypothesis never depended on intensity decrease, and the charge of nonreplicability is incorrect. Siddle's argument concerning response stereotypy cannot account for the data showing response to significant 'novelty' coupled with nonresponse to nonsignificant 'novelty' in the same OR component, or for that showing consistent differences in various components between randomly selected groups. Arguments based on trait-lability are inadequate since tests of the lability hypothesis have confounded trait factors with the differences in stimulus assessment they hope to test. The significance hypothesis emphasizes stimulus information in the OR, significance serving to limit access to central processing channels to those signals whose information is relevant for the organism. OR components are seen as long-latency responses elicited after automatic early detection of uncertainty and significance, and reflect higher processing of significant information. A distinction between involuntary and voluntary phases of attention is acknowledged, but it is questioned whether OR components can be assigned to the former because of the frequent failure of 'automatic' ORs to innocuous stimuli, the long latency of most components, and failure to demonstrate structural differences between the classes of response.

Animals↗
PubMedDate not supplied

An analysis of the skin conductance orienting response in samples of American, British, and German schizophrenics.

The existing literature dealing with the phasic orienting response (OR) in schizophrenia, examining, for the most part, the skin conductance component (SCOR), reports conflicting results with divergent implications for the nature of the attentional dysfunction in these patients. The present authors have contributed to that literature and to its divergencies. The present report addresses this issue by applying a common set of response definitions and uniform statistical-analytic procedures to the previously gathered electrodermal data obtained independently in each author's laboratory. A total of 14 studies is involved, drawn from six laboratories in the U.S.A., the U.K., and West Germany. Collectively, these studies examine chronic and acute schizophrenics, males and females, those receiving neuroleptic drugs and those not receiving them, recording SCOR from either (or both) hands using a variety of instruments and somewhat differing instructions and conditions, to both auditory and visual stimuli of different intensities and rise-time properties. The authors' purpose is two-fold. First, to determine whether some 'universal' dysfunction can be demonstrated across laboratories, conditions, and samples. Given the heterogeneous origins of these data such a finding would offer fairly strong evidence of 'real' dysfunction in schizophrenia. Second, where disagreement exists, to describe the scope and nature of the disagreement, and to articulate more clearly the findings on each side of a disputed area. One such 'universal' dysfunction emerged. Consistently, schizophrenics displayed an abnormally high incidence of nonresponsiveness, involving nearly 50% of the schizophrenic sample on average. The next most common finding is that many of the schizophrenics who display an SCOR often habituate faster than do nonschizophrenic responders. This was seen in a majority of the studies and laboratories, but conflicting evidence was presented by a minority. Evidence for a dysfunction simultaneously involving SCOR hypo- and hyper-responsiveness within schizophrenia was obtained, but in a minority of studies. The possible effects of neuroleptic drugs, stimulus intensity and rise-time factors, and differential significance evaluation on these findings was discussed. The possibility that schizophrenic dysfunction involves the input-facilitating OR but not input-attenuating 'protective' responses is examined. The correlates of hyporesponsiveness in schizophrenia, including physiological response patterns, clinical symptom patterns, and specific input deficiencies, is also examined. Several areas are noted where systematic research has only begun, and further study is particularly needed.

Adolescent↗
PubMedDate not supplied

The autonomic orienting response and CT scan findings in schizophrenia.

CT scan measures of prefrontal sulcal prominence, parieto-occipital sulcal prominence, ventricle-brain ratio (VBR), and third ventricle width (TVW) were examined in 24 schizophrenic patients who were grouped on the basis of their autonomic orienting response (OR) status. A two-component definition of the OR was used that required concordance across both electrodermal and finger pulse volume components for response status assignment. The nine OR responders had significantly greater TVW than the 15 OR nonresponders. Although OR responders had higher values also on the other CT scan measures, these differences were not significant. These findings are consistent with the possibility that OR responsiveness and nonresponsiveness are related to different pathological dimensions of schizophrenia.

Arousal↗