Valproate dosage

Starting from Valproat dosage recommendations and serum levels and patient risk from acute hepatic failure, the results of our therapeutic service are set forth. The question comes up for discussion as to whether the proposal of Mattson et al. of a mean therapeutic blood level of between 40 and 45 micrograms per ml should be aimed at.     

Speed and accuracy of saccadic eye movements: characteristics of impulse variability in the oculomotor system

Dynamic characteristics observed in the trajectories of saccadic eye movements reveal systematic variability of the force pulses used to move the eyes. This variability causes saccades to exhibit a linear speed-accuracy trade-off: As the average distance and duration of saccades toward specified target points increase, the standard deviations of saccadic-movement endpoints increase linearly with the saccades' average velocity. The linear trade-off, and other observed stochastic properties of saccades, may be attributed to noise in neuromotor processes and may be described in terms of an impulse-variability model originally designed for characterizing limb movements. According to the model, both eye and limb movements are controlled through stochastic force and time parameters that govern movement kinematics. Such an account may promote a unified conceptual framework for understanding a wide range of motor behavior.     

Cognitive appraisal and attributional correlates of depressive symptoms in children

This study examined differences in cognitive appraisal and causal attributions in response to a task among schoolchildren reporting high and low depressive symptomatology. From a sample of 361 fifth- and sixth- grade students, 72 children were classified as depressed or nondepressed on the basis of their scores on the Children's Depression Inventory. They were then presented with modified Picture Arrangement problems from the WISC- R and questioned about their performance. Pretask expectations, evaluations, and future expectations of performance for the self and that of same- aged peers were assessed, as well as causal explanations for solvable and unsolvable problems. Despite similar performance, the depressed group of children provided lower evaluations for themselves than for others on all three measures of self- appraisal, whereas the nondepressed group did not show this tendency. Further, the attribution results indicated that the two groups differed in their explanations for failure, with the depressed group emphasizing the importance of ability in failure and the nondepressed group emphasizing factors other than ability. Overall, the results provide support for the presence of negative cognitions and self- defeating attributional style among depressed relative to nondepressed children, as well as pointing to the importance of social comparison processes in depression.This research was supported by studentships to Nancy Meyer from the Manitoba Health Research Council and subsequentlv from the Social Sciences and Humanities Research Council, and by a grant to Dennis Dyck from the Natural Sciences and Engineering Research Councel of Canada. The research was done in partial fulfillment of the first author's master's degree in the Department of Psychology at the University of Manitoba.We would like to thank Rhea Brooks, April Machej, and Colleen Singbeil, for their assistance in the study; John Schallow, John Whitely, Lillian Esses, and Mike Thomas, for their helpful suggestions; and the teachers, administrators, and parents of Assiniboine South #3 School Division, for their cooperation and support.     

Common-sense models of illness: the example of hypertension

Our premise was that actions taken to reduce health risks are guided by the actor's subjective or common-sense constructions of the health threat. We hypothesized that illness threats are represented by their labels and symptoms (their identity), their causes, consequences, and duration. These attributes are represented at two levels: as concrete, immediately perceptible events and as abstract ideas. Both levels guide coping behavior. We interviewed 230 patients about hypertension, presumably an asymptomatic condition. When asked if they could monitor blood pressure changes, 46% of 50 nonhypertensive, clinic control cases said yes, as did 71% of 65 patients new to treatment, 92% of 50 patients in continuing treatment, and 94% of 65 re-entry patients, who had previously quit and returned to treatment. Patients in the continuing treatment group, who believed the treatment had beneficial effects upon their symptoms, reported complying with medication and were more likely to have their blood pressure controlled. Patients new to treatment were likely to drop out of treatment if: they had reported symptoms to the practitioner at the first treatment session, or they construed the disease and treatment to be acute. The data suggest that patients develop implicit models or beliefs about disease threats, which guide their treatment behavior, and that the initially most common model of high blood pressure is based on prior acute, symptomatic conditions.     

Do optimism and pessimism have different relationships with personality dimensions? A re-examination

The classic, well-cited study by Marshall et al. (1992) demonstrated that optimism correlates stronger with extraversion than does pessimism and pessimism correlates stronger with neuroticism than does optimism, and these results lent support to their claim that optimism and pessimism are two separate constructs. However, we argued that their results are likely the outcome of scale artefact caused by item valence (or item favorability). In an empirical study (N = 1016), we evaluated the correlation of optimism scores and pessimism scores with the most common measure of optimism - Life Orientation Test-Revised (LOT-R). As expected, when item valence effect was not controlled, we replicated the finding by Marshall et al. (1992) that optimism and pessimism show differential correlations with extraversion and neuroticism. After item valence was controlled such pattern of relationships was greatly reduced. Suggestions for future research to resolve the dimensionality debate for optimism-pessimism are discussed.     

The cognitive capabilities of farm animals: categorisation learning in dwarf goats (Capra hircus)

The ability to establish categories enables organisms to classify stimuli, objects and events by assessing perceptual, associative or rational similarities and provides the basis for higher cognitive processing. The cognitive capabilities of farm animals are receiving increasing attention in applied ethology, a development driven primarily by scientifically based efforts to improve animal welfare. The present study investigated the learning of perceptual categories in Nigerian dwarf goats (Capra hircus) by using an automated learning device installed in the animals' pen. Thirteen group-housed goats were trained in a closed-economy approach to discriminate artificial two-dimensional symbols presented in a four-choice design. The symbols belonged to two categories: category I, black symbols with an open centre (rewarded) and category II, the same symbols but filled black (unrewarded). One symbol from category I and three different symbols from category II were used to define a discrimination problem. After the training of eight problems, the animals were presented with a transfer series containing the training problems interspersed with completely new problems made from new symbols belonging to the same categories. The results clearly demonstrate that dwarf goats are able to form categories based on similarities in the visual appearance of artificial symbols and to generalise across new symbols. However, the goats had difficulties in discriminating specific symbols. It is probable that perceptual problems caused these difficulties. Nevertheless, the present study suggests that goats housed under farming conditions have well-developed cognitive abilities, including learning of open-ended categories. This result could prove beneficial by facilitating animals' adaptation to housing environments that favour their cognitive capabilities.     

The contributions of encoding,retention, and recall to the Hebb effect

The article reports an experiment testing whether the Hebb repetition effect—the gradual improvement of immediate serial recall when the same list is repeated several times—depends on overt recall of the repeated lists. Previous reports which suggest that recall is critical confound the recall manipulation with retention interval. The present experiment orthogonally varies retention interval (0 or 9 s) and whether the list is to be recalled after the retention interval. Hebb repetition learning is assessed in a final test phase. A repetition effect was obtained in all four experimental conditions; it was larger for recalled than non-recalled lists, whereas retention interval had no effect. The results show that encoding is sufficient to generate cumulative long-term learning, which is strengthened by recall. Rehearsal, if it takes place in the retention interval at all, does not have the same effect on long-term learning as overt recall.