The nature of deficits in attention in closed head injury (CHI) was studied by three reaction time (RT) paradigms given to 20 patients who had a CHI 2 or more years previously and to 25 controls. We studied the effects of temporal uncertainty by varying the length and regularity of the preparatory interval, the effects of stimulus modality uncertainty on simple RT to tones and lights, and the effects of response selection in choice RT. The CHI group showed slower and more variable RT than controls under all conditions. In addition, a long preparatory interval on the preceding trial retarded RT more in the CHI group, and they showed greater effects of stimulus modality uncertainty. Both of these findings suggest a difficulty in shifting attention to unexpected stimuli. These greater effects on RT of variations of attention or preparation in CHI may account for their greater within-subject variability possibly due to frontal lobe damage.

To study the pharmacological induction of stress along with psychological stress and their possible interaction, 20 mg yohimbine and placebo orally were administered to 8 panic patients on placebo treatment, 7 panic patients on alprazolam treatment and 12 controls in a double-blind crossover design. Two structured situations which can be considered as ‘neutral’ stressors were included: a mental arithmetic task and a continuous performance task. Mental arithmetic induced robust increases in ratings of panicky, anxiety, nervousness, heart rate and electrodermal activity, while the continuous performance task induced increases exclusively in skin conductance reaction. Patients responded to these tasks less than controls with regard to subjective ratings and electrodermal activity. Yohimbine did not potentiate the response to the tasks in the patients. In controls, heart rate during the mental arithmetic task, but not during rest, was increased after yohimbine. In contrast to other yohimbine challenge studies no panic attacks were observed. It is hypothesized that the experimental design together with an instructional set that reduces expectancy factors and the inclusion of structured and timelimited tasks in a challenge paradigm is able to reduce the anxiogenic effects of yohimbine.

Boys with diagnoses in the disruptive behavior disorder (DBD) spectrum and normal controls were tested in two reaction time (RT) experiments. In Experiment I simple warned RT was measured and the length and regularity of the preparatory intervals were varied in order to study sustained attention in the sense of preparation. With age and IQ controlled, DBD boys had slower and more variable RT overall than controls and showed generally more pronounced effects of variations in the length and sequence of the preparatory intervals. The results suggest that DBD boys are subject to lapses of attention which are increased by a relatively long preparatory interval, and that they have a particular problem with temporal uncertainty. In Experiment II some aspects of selective attention were studied in a paradigm in which stimulus modality uncertainty and response selection were varied. DBD boys showed greater effects of modality uncertainty but not response selection than controls. No differences between subdiagnoses within the DBD spectrum could be demonstrated.

The effects of caffeine on autonomic activity were tested in 19 normal prepubertal boys. Subjects received placebo, 3 mg/kg, and 10 mg/kg caffeine in a random order (double blind) before three test sessions 48 h apart. Skin conductance (SC), heart rate (HR), and skin temperature (ST) were recorded during a rest period, a series of nonsignal tones, and a simple reaction time (RT) task. Caffeine increased the frequency of both spontaneous and elicited SC responses (SCR) under all conditions. Resting SC base level (SCL) was increased, and shorter SCR half recovery time also occurred in some periods. In contrast, caffeine decreased HR and motor activity at 3 mg/kg. Evidence of improved attention on caffeine was also obtained. The physiological effects are partially similar to the effects seen in clinical anxiety states, and they are also consistent with the physiological concomitants of good sustained attention. The profile of effects did not resemble those of dextroamphetamine in a similar population.

The effects of caffeine on autonomic nervous system (ANS) activity were tested in 20 adult males who were either high or low consumers of caffeine. Subjects received placebo, 3 mg/kg, and 10 mg/kg of caffeine in a counterbalanced order (double-blind) before 3 test sessions 48 h apart. Skin conductance (SC), heart rate, and skin temperature (ST) were recorded during a rest period, a series of non-signal tones, and a simple reaction time task. Caffeine increased resting electrodermal activity (EDA) and increased the SC orienting response to the first non-signal tone, but reduced the increase in tonic EDA due to task performance. ST was reduced by caffeine in both rest and task periods. Increases in nervous/jittery ratings occurred after caffeine ingestion, but task performance was not affected. Low consumers of caffeine showed significantly more ANS responsivity than high consumers under all conditions and did not differ in ANS, behavioral, or subjective effects of caffeine. The acute physiological changes are partly similar to those reported for patients with anxiety disorders, suggesting a possible role of ANS activity in mediating the anxiogenic effects of caffeine. Effects of user status may reflect a predisposing trait, but an effect of chronic caffeine use on ANS sensitivity cannot be ruled out.

We measured arterial and venous plasma catecholamines and used laser-Doppler flowmetry to measure cutaneous microcirculatory flow in the sympathectomized and in the intact limbs of 3 patients who had undergone regional sympathectomies. Venous concentrations of norepinephrine, the sympathetic neurotransmitter, exceeded arterial concentrations in the intact limbs—a normal finding—but invariably were less than arterial in the sympathectomized limbs of the same patients, both during baseline conditions and during sympathetic stimulation using tilt, standing and the cold pressor test (mean arteriovenous decrement about 40%). Arterial epinephrine levels exceeded venous levels with or without sympathectomy. Skin microvascular flow rapidly decreased during the cold pressor test and the Valsalva maneuver in the intact but not in the sympathectomized limbs, and spontaneous flow oscillations occurred in the sympathectomized limbs. The results suggest that an arteriovenous increment in plasma norepinephrine reflects local release of norepinephrine from sympathetic nerve endings, whereas removal of circulating catecholamines can occur with or without sympathetic neural impulses. Laser-Doppler flowmetry can measure reflexive sympathetically mediated responses of skin microvascular flow and so can detect sympathetic denervation. Spontaneous oscillations in this flow may not depend exclusively on oscillations in the activity of the sympathetic microvascular innervation.

In a double-blind sham replacement study, eight drug-free schizophrenic patients underwent 10 active and 10 sham hemodialysis for 20 weeks. At the end of the 10 active dialyses, none of the patients appeared to be improved in psychotic, affective, or social symptoms. Active dialysis was associated with a "startle" response in heart rate and skin conductance to auditory stimuli, while sham dialysis was associated with an "orienting" response. Night-recorded sleep electroencephalography was unaffected by active dialysis. Spinal fluid beta-endorphin-like immunoreactivity levels were unchanged after active treatment. The behavioral improvements reported in other studies may be related to "stress," psychotherapeutic support, spontaneous remissions, neuroleptic withdrawal, denial of symptoms, or diagnostic differences. This study did not confirm the claims for hemodialysis as a specific therapeutic intervention in schizophrenia.

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.

The hypothesis is tested that the response to dextroamphetamine in terms of activity, attention, impulsivity, and autonomic activity is similar in normal (N) and hyperactive (H) children. Fourteen N and 15 H boys had skin conductance (SC), heart rate (HR), and finger temperature (ST) recorded during rest, presentation of eight 75-dB tones, and a reaction time (RT) procedure on three occasions: off drug (Day 1) and after ingestion (double-blind) of placebo and of .5 mg/kg dextroamphetamine. Both N and H groups showed drug effects, compared to placebo, of reduced motor activity and impulsivity, improved attention (RT), increased HR and HR slowing during RT foreperiods, and decreased ST. Both groups also had decreases in SC responsivity but in different parts of the test. Placebo compared to Day 1 produced increased activity and autonomic "arousal" but no change in Rt. Stimulant drugs thus have similar behavioral and autonomic effects in both N and H boys, but the beneficial effects on behavior do not depend critically on increases in arousal.

This study tested the covariation hypothesis of nervous typological theory that normals scoring high arid low on a psychoticism measure would show the same covariation patterns for psychophysical and autonomic nervous system measures at the low range of arousal as that found for comparisons of normal and psychiatrically sick individuals. Using scores from the latest forms of the Eysenck psychoticism and neuroticism scales, a group of male college students were divided into high P, high N and low N groups. Use of the constant stimuli method for presentation of two‐flash threshold (TFT) stimuli provided estimates of not only threshold but response criterion and sensory sensitivity scores as well. At the low range of arousal, high P subjects showed a covariation pattern opposite to that of both low P groups for threshold and skin conductance, heart rate and spontaneous response scores. Response criterion and sensory sensitivity measures showed similar but weaker trends in the same direction. These results were viewed as providing only limited support for the covariation hypothesis since only a few of the correlations reached acceptable significance levels.

It is difficult to know just how Schneider (1978) regards the disproportionate deficit in the reaction time (RT) of schizophrenics on trials for which the preparatory interval on the preceding trial (PPI) is longer than the preparatory interval (PI) on the current trial. At various times in his paper he refers to this PPI-PI effect as a "thesis," a "concept," and finally as an "epiphenome-non" (but doesn't say of what). First, it must be clear to most readers of Nuechterlein's (1977) review that the PPI-PI effect is indeed a well-confirmed empirical phenomenon rather than a thesis or concept. With the PI held constant , the RT of schizophrenics is influenced more by variations in the PPI than is the case in nor-mals. Moreover, the greater overall effect of the PI in a balanced irregular series must be partly an "epiphenomenon" of the PPI effect since the shorter Pis in the series are more frequently preceded by longer PPIs. Given the reality of this phenomenon , the question is how is it to be explained by existing or new theories of schizophrenic deficit? In attempting to refute Shakow's segmental set hypothesis, Schnei-der makes some assumptions of his own, namely that Shakow assumes that the schizophrenic bases "a disproportionate amount of attention on the PI of the immediately preceding trial," that in order for the PPI effect to exist a "very precisely recorded and immediately available 'trace'. .. of the PPI must have been formed and at hand for continuous comparison throughout the PI," and that the theory demands that the schizophrenic "be accredited with unusually consistent and high powers of concentration" (p. 154). It may be true that a model containing these assumptions is incompatible with the empirically demonstrated PPI effect. However , Shakow's hypothesis neither makes nor requires these assumptions. It states that the preparatory set of the schizophrenic on a given trial is disproportionately influenced by the characteristics of the preceding trial relative to the influence of entire series of preceding trials. To be influenced by an event is not at all the same as attending to that event. Shakow uses "generalized set" and "major set" interchangeably (Shakow 1963, p. 302). This emphasizes the relational nature of the formulation. The theory by no means requires the assumption of greater attention, more persistent traces, or higher powers of concentration in an absolute sense in schizo-phrenics. Schneider's gratuitous assumptions are so …

This study attempted to replicate and extend previous findings on autonomic arousal and responsivity in children with diagnoses of minimal brain dysfunction (MBD). Pupil size, heart rate, skin conductance, and skin temperature were recorded from 32 MBD and 45 control children during a session that included presentation of visual stimuli, simple reaction time (RT), a cold pressor procedure, and rest periods. The MBD children were tested both off and on clinical dosages of stimulant drugs in a crossover design. Evidence of higher than normal arousal levels in the unmedicated MBD Ss was obtained from resting skin conductance and, more tenuously, from pupil size. Lower phasic responsivity in the MBD children was evidenced by slower RT, less cardiac deceleration to both light and RT stimuli, and smaller pupil dilation to the RT stimuli. Spontaneous pupillary constrictions during "rest" periods, presumably indicating drowsiness, were observed about equally in MBD and control children. Stimulant drugs raised arousal levels but did not reverse the responsivity deficits. The lower phasic reactivity in the MBD group and the effects of stimulant drugs on arousal indices confirm earlier reports. The finding of higher arousal in drug-free MBD children is incompatible with the low arousal hypothesis of MBD but is consistent with a previous report of the effects of a stimulating environment on these children.

ABSTRACTThe autonomic nervous system activity and mood ratings of 12 women were studied 6 days a week for a complete menstrual cycle. The daily procedure consisted of a resting period, a series of 5 mild tones, time estimation (TE), and reaction time (RT) trials, and a final resting period. Significant increase in heart rate (HR), respiration rate, and body temperature, and a significant decrease in resting skin conductance (SC) were found during the luteal phase. During the ovulatory phase there were significant increases in autonomic responsivity, as shown by greater amplitude of SC response in the TE and RT situations as well as in faster SC drop‐rate and greater HR variability. All of these autonomic variability measures coincided with a significant peak in feelings of elation and vigor.Significant age effects were that older women had higher basal body temperatures, less marked HR variability, and tended to have lower levels of SC, particularly in the luteal phase of the cycle. The results are discussed in terms of the psychophysiological effects of estrogen and progesterone.

This study attempted to separate the relative roles of experiential and genetic factors in the etiology of schizophrenia by studying the psychiatric and psychological characteristics of a group of adopting parents of schizophrenics and comparing these parents with the biological parents of schizophrenics and the adopting parents of normal subjects. The results indicate that the biological parents of schizophrenics are appreciably more disturbed than the adopting parents of schizophrenics, who are in turn slightly more disturbed than the adopting parents of normals.