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In a number of reports, Gruzelier and Venables have demonstrated that about 50% of the schizophrenic population do not show the skin conductance orienting response (S.C.O.R.), while those that do respond, do not show normal habituation. Zahn (Orienting response in schizophrenics. J. Nerv. Ment. Dis., 162: 195-199, 1976) has questioned the bimodality of the S.C.O.R. in schizophrenia and suggests that responding/nonresponding could well be due to differential effects of phenothiazine medication. In two experiments (with equally medicated patients), in two different hospitals, the present report confirms the finding of a large proportion of nonresponding in schizophrenia but also suggests that both normal and nonhabituation are seen within schizophrenics and normals. Differential pupillary dilation and constriction parameters are seen in responders and nonresponders although both of these patient groups show tachycardia (the most usual effect of phenothiazines) in comparison to the normal group. The results do not fit easily into the differential effect of phenothiazines hypothesis proposed by Zahn.

Objectives: The objectives of this study were to determine if monitoring of intraoperative somatosensory evoked potentials could be used to detect stroke during cardiac operations and to establish indicators of cerebral ischemia based on changes in these potentials. Methods: Twenty-five patients undergoing cardiac operations underwent preoperative and postoperative neurologic examinations as well as intraoperative recording of somatosensory evoked potentials. Detailed analysis of the waveforms of these potentials was performed. Results: Two of the 25 patients had intraoperative strokes. These patients and only these patients had changes in their somatosensory evoked potentials during the operation suggesting cerebral ischemia. The unilateral disappearance of the cortical somatosensory evoked potential waves correlated significantly with the clinical outcome of stroke (p < 0.004). Ischemic changes were detected in real time and were related to the removal of the aortic crossclamp in one patient and to the initiation of cardiopulmonary bypass in the other. Conclusions: Somatosensory evoked potentials can detect intraoperative stroke during cardiac operations. Acute, unilateral decreases in amplitude of the cortical potential are more useful than changes in latency in detecting intraoperative stroke. (J THORAC CARDIOVASC SURG 1996;112:962-72)

A group of 31 chronic male shizopherics were found to be heterogeneous with respect to skin conductance recovery, when response was made to non-signal tones. Fast skin conductance recovery was related to slow pupillary constriction in the light/dark reflex. Conversely, slow skin conductance recovery was related to fast pupillary constriction in the light/dark reflex. The cholinergic nature of pupillary constriction and the implications of these findings for a generalized cholinergic hypothesis of schizophrenia are discussed.

Research with schizophrenics is reviewed in the areas of the startle reflex, subject-initiated evoked potentials, and two-stimulus evoked potentials. A hypothesis of an early (pre-100 ms) information-processing deficit is posited and further refined by results presented from brain evoked potentials during a backward-masking experiment. The implications of these findings for the speech component of schizophrenic thought disorder are speculated upon, with specific reference to failures of temporal sequencing control that may underlie schizophrenic speech dysfunction and may be attributable to defective thalamic control. Recent neuroanatomical findings of abnormalities in the hippocampus and thalamus of schizophrenics are presented, and considered as likely contributors to the early information-processing deficits posited.

Three electrodermally distinct subgroups of chronic schizophrenics were identified by Patterson and Venables (1978). The present study investigated the auditory vigilance ability of these subgroups relative to a normal population. In one subgroup of schizophrenics (the fast habituators) no evidence could be found for a deficit in auditory vigilance ability relative to normal. Implications for further electrophysiological and biochemical research in schizophrenia are discussed.

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 sympton patterns, and specific input deficiencies, is also examined. Several areas are noted where systematic research has only begun, and further study is particularly needed.

Chronic schizophrenics from three different hospitals were compared to normal subjects on skin conductance parameters. In addition to “Responders” and “Nonresponders” as reported by Gruzelier and Venables (1972), a group of “Fast Habituator” schizophrenics was found. These subjects produce one or at most two responses before habituation in an orienting series. The SC waveform of fast habituator subjects shows long latency, slow risetime and long recovery, although the amplitude of response is within normal limits.

In addition to introducing the six articles joined by our thematic outlook, this article addresses the importance of subcortical structures as they may be related to information processing and the life experience of schizophrenic patients. This is a heuristic exercise aimed at bridging the conceptual gaps between clinical and research approaches to schizophrenia. A brief overview is then provided of current conceptualizations of a number of subcortical structures, each of which may play a part in the subcortical pathogenesis of schizophrenia in specific patients. The central concepts are failures in the "automaticity" with which prior experience may be recreated in parallel with current stimulus input in schizophrenia (with concomitant failures in future orientation or contextually generated expectancy), and the view of subcortical structures as constituting a "system" in which no single type of defect may be common to all schizophrenic patients.