The mediating role of anxiety in self-reported somatic complaints of depressed adolescents

This study examined the mediating role of anxiety in the self-reports of somatic complaints in 96 depressed adolescent inpatients. Sixty-four subjects with major depressive episodes and comorbid anxiety disorders (MDE-A) determined from the Diagnostic Interview for Children and Adolescents-Revised (DICA-R) reported significantly more somatic complaints than 32 adolescents having major depressive episodes without comorbid anxiety (MDE). An analysis of covariance demonstrated that, with anxiety symptoms controlled, MDE and MDE-A groups did not differ significantly in somatic complaints. A hierarchical multiple-regression analysis revealed that, with demographic and anxiety symptoms controlled, depressive symptoms did not contribute to the explanation or prediction of somatic complaints. The results suggest that anxious, but not depressive symptoms, are independently associated with somatic complaints. The results are discussed in light of new affective models of psychopathology.     

Measuring and predicting the effects of alcohol consumption on contrast sensitivity for stationary and moving gratings

Contrast sensitivity was measured for 12 healthy young males while sober, after ingestion of an alcohol placebo, and after ingestion of alcohol (95% grain alcohol; mean estimated blood alcohol level = .088%). Observations were made for both stationary gratings and gratings that traveled through a circular path and required pursuit eye movements. The significant alcohol-related reduction in contrast sensitivity was 2.6 times greater for moving (.29-log-unit reduction) than for stationary gratings (.11-log-unit reduction). The loss in contrast sensitivity for the moving gratings of high spatial frequency (12 cpd) was particularly severe (.37 log unit). Estimated blood alcohol level was correlated with the loss in contrast sensitivity for moving gratings (r = .61), but not with the loss for stationary gratings. Estimated blood alcohol level was strongly correlated with the difference between the loss in contrast sensitivity to moving and stationary gratings (r = .75). These results are consistent with reports that alcohol consumption degrades the ability to make pursuit eye movements. Subjects’ perceived intoxication level was not a reliable predictor of any index of visual performance.     

When are supercomputers worth the bother?

The availability of the UNIX operating system on large supercomputers has greatly simplified the importation of research software from workstations and minicomputers. Supercomputers generally offer much greater memory and storage than do smaller machines, which may make their use mandatory for some large applications. Realization of the full performance offered by vectorizing supercomputers such as the Cray C90 sometimes requires modification of existing code. The use of high-level interpreters for the development of applications is recommended, to minimize the amount of compiled code that must be optimized.     

The φ-maze: A versatile automated T-maze for learning and memory experiments in the rat

The φ-maze is a novel implementation of the T-maze that can be used for various behavioral experiments. It consists of a start/goalbox from which a central alley leads to a choice point. Left and right arms return to the start/goalbox, where reinforcers are delivered. A holding chamber at the choice point can be used for delayed (non)matching-to-sample experiments. Lamps mounted under the translucent acrylic floor serve as visual stimuli. The design incorporates reliable and inexpensive automated guillotine doors and a modification of a commercially available pellet dispenser that allows the automated dispensing of Froot Loop reinforcers. The φ-maze has been used successfully in experiments involving spatial and visual alternation, visual discrimination, and delayed matching-to-sample.