Attenuation of amphetamine-stereotypy by mesostriatal dopamine depletion enhances plasma corticosterone: implications for stereotypy as a coping response

The relationship between amphetamine-induced stereotyped behavior and a neuroendocrine index of arousal, plasma corticosterone (CCS), was investigated. 6-Hydroxydopamine lesions of the caudate-putamen, which produced dopamine depletions of 60%, blocked stereotypy and prolonged the elevation in corticosterone associated with d-amphetamine treatment (5 mg/kg). Similar dopamine depleting lesions of the nucleus accumbens, which attenuated the locomotor, but not the stereotypic, response to AMPH did not have this effect on CCS. This pattern of results supports the hypothesis that stereotypy has a coping function which may serve to alter arousal and further suggests important differences between the nigrostriatal and mesolimbic dopamine projections in modulating the responsiveness of the neuroendocrine system. These results have implications for understanding the function of behavioral stereotypies common to a number of psychopathological conditions, including schizophrenia and childhood autism.     

Visual gap and offset discrimination and its relation to categorical identification in brief line-element displays

Visual processing was investigated in judgments of relative line position. Stimulus continua were generated by bisecting a straight line and displacing the segments. Experiment 1 measured discrimination of pairs of longitudinally displaced segments at equal steps along the continuum. At long (2 s) durations discrimination fell smoothly, but at short (100 ms) durations it was sharp-peaked. In Experiment 2 the short-duration stimuli were labeled with subsets of the labels no gap, just a gap, and more than just a gap. Theoretical discrimination performances were computed and the one based on no gap and just a gap closely fitted observed performance. Experiments 3 and 4 were similar to 1 and 2, with lateral replacing longitudinal displacement. Similar "categorical" performance was obtained. It was concluded that there are discrete mechanisms for early detection of relative line position and that 2 labels can be used to characterize performance in each direction.     

The effect of response bias on recall performance, with some observations on processing bias

We explored Roediger and Payne's proposal that response bias does not affect recall performance and that it is therefore not necessary to control for response productivity in recall studies. Two initial experiments, contrary to expectation, corroborated Roediger and Payne's findings: Forced recall did not produce more correct recalls than free recall, even though forced recall produced substantially more false alarms than did free recall. However, in succeeding experiments involving pictorial and verbal stimuli, reliable response-bias effects on recall were demonstrated. The stimuli yielding response-bias effects were those associated with higher probabilities of being guessed by chance. In addition, some of the data suggest that processing-bias effects (differential retrieval effort) may be unintentionally induced by instructions and may significantly affect recall memory. Consequently, it is necessary to assess or to control response-bias effects and, possibly, processing-bias effects in recall experiments in which level of recall is of interest.     

Aversiveness of denatonium saccharide and quinine in grasshopper mice Onychomys leukogaster

The responses toward denatonium saccharide and quinine by three rodent species differ from those exhibited by humans. This study measured the relative aversiveness of these two compounds in grasshopper mice (Onychomys leucogaster) to determine if this species responded similarly to or differently from these other rodents. In a choice test, the mice clearly preferred quinine over denatonium saccharide at concentrations of 1/10,000 and 1/50,000, but only marginally preferred quinine at a concentration of 1/1000. When denatonium or quinine was paired with toxicosis, both suppressed drinking at concentrations from 1/10,000 to 1/50,000, but only denatonium suppressed drinking at 1/100,000. Neither compound suppressed drinking at 1 part in million. Grasshopper mice perceived denatonium saccharide as more aversive than quinine in both experiments. Such a response resembled the behavior of humans more than that of the other three rodents previously tested.     

Length of survival and lymphocyte percentage in women with mammary cancer as a function of psychotherapy

50 patients suffering from terminal mammary cancer and visceral metastases received chemotherapy, and in addition half of them received psychotherapy, while half did not. A lymphocyte count was undertaken seven times in all, once before initiation of chemotherapy, the others after six applications of the therapy. As hypothesized, the 25 women who received psychotherapy lived longer and had significantly higher lymphocyte counts on Occasions 5, 6 and 7 than did the 25 women who did not receive psychotherapy. Of the types of psychotherapy employed, a specially designed form of behaviour therapy was significantly more helpful than dynamic psychotherapy in prolonging life.     

Alcoholism and morphologic findings of the nervous system in autopsy cases

154 autopsy cases of alcoholics (120 men and 34 women) were investigated from a neuropathological viewpoint. In only 19 cases could typical diseases of the nervous system caused by alcoholism be found (Wernicke's encephalopathy, central pontine myelinolysis, Marchiafava-Bignami's disease and disorders of the peripheral nerves and muscles). In comparison liver diseases occurred almost five times more frequently in our own material. Diseases caused by alcoholism of the nervous system, the question of brain shrinkage and its partial reversibility, the up to now not completely known effects on the neurophil and cortical cytoarchitectonic are discussed according to the literature.     

Clinical judgment, clinical training, and professional experience

Reviews studies on training, experience, and clinical judgment. The results on the validity of judgments generally fail to support the value of on-the-job experience in mental health fields. The validity results do provide limited support for the value of training. Other results suggest that experienced clinicians are better than less experienced judges at knowing which of their judgments are likely to be correct and which are likely to be wrong. Reasons why clinicians have trouble learning from experience are given. Recommendations are made for improving training and clinical practice.     

The perception of temporal deviations in isochronic patterns

In a study of perceptual synchronization with an isochronic sequence, subjects were given the following task: They heard an isochronic sequence of tones in which the last interval was either correct or too long. Their task was to detect irregularity. The independent variables were the number of tones heard and the time interval between them. The dependent variable was the difference limen (DL) for the detectability of the irregularity. Two experiments were performed in this study, differing in the way in which the trials were blocked: In Experiment 1, stimuli with the same period were presented in blocks, whereas in Experiment 2, the period of the stimulus was randomized. The results show that in Experiment 1 the number of tones in the stimulus did not affect the detectability of the anisochrony. In Experiment 2, the number of the DL was a decreasing function of the number of tones heard. Moreover, the decrease of the DL was larger than one would expect from a simple model of information integration, which assumes that subjects improve their performance by averaging their percepts of the first intervals in the sequence. The difference between this task and experiments on the discrimination of temporal intervals is discussed.     

Negative afterimages and the McCollough effect

Four experiments were conducted to test earlier claims about the relationship between the negative afterimage and the McCollough effect. The first claim (Hansel & Mahmud, 1978) is that long-lasting afterimages occur when induced by the same alternating-stimulus procedure as that used to induce the McCollough effect. The second claim (Murch & Hirsch, 1972) is that afterimages can themselves induce McCollough effects if they are induced and paired sequentially with grating patterns. In testing these claims, a reliable computer-controlled color-cancellation technique developed earlier was used to measure the apparent color of both afterimages and McCollough effects objectively. No support was found for the first claim following alternative presentation of two homogeneously colored regions for total periods of 5 min (Experiment 1) and 20 min (Experiment 2). The second claim was fully supported: After an induction period of 7.3 min, a McCollough effect occurred for a red-vertical pairing but not for a green-horizontal pairing (Experiment 3); but after an induction period of 20 min, McCollough effects occurred strongly for both pairings (Experiment 4). The theoretical implications of these outcomes are considered in the context of recent theories of color and pattern processing in the visual system.