Clamped Corticosterone (B) Reveals the Effect of Endogenous B on Both Facilitated Responsivity to Acute Restraint and Metabolic Responses to Chronic Stress

To determine the effects of both corticosterone (B) and chronic stressors on acute ACTH responses to restraint, young male rats were exposed to streptozotocin-induced diabetes, cold (5-7 degreesC) or intracerebroventricular (icv) neuropeptide Y (NPY) for 5 d and then exposed to restraint within 2 h after lights on. Two groups of rats were studied: intact and adrenalectomized replaced with B pellets that maintained plasma B in the normal mean 24-h range of intact rats. In addition to ACTH and B responses to restraint on d 5, body weight, food intake, fat depots, glucose and other hormones were measured to determine the role of stress-induced elevations in B on energy balance. ACTH responses to restraint were normal in intact rats subjected to diabetes or cold. By contrast, there was no ACTH or B response to restraint in NPY-infused intact rats. All 3 groups of chronically stimulated adrenalectomized rats with clamped B had facilitated ACTH responses to restraint compared to their treatment controls. Overall food intake increased in all groups of stressed rats; however, augmented intake occurred only during the light in intact rats and equally in the light and dark in B-clamped rats. White adipose depot weights were decreased by both diabetes and cold and increased by NPY in intact rats; the decreases with cold and increases with NPY were both blunted and changes in fat stores were not significant in adrenalectomized, B-clamped rats. We conclude that: 1. diabetes- and cold-induced facilitation of restraint-induced afferent input to hypothalamic control of the hypothalamo-pituitary-adrenal (HPA) axis is opposed in intact rats by the elevated feedback signal of B secretion; 2. NPY does not induce facilitation of afferent stress pathways; 3. chronic stimulation of the HPA axis induces acute hyperresponsiveness of hypothalamic neurons to restraint provided that the afferent input of this acute stimulus is not prevented by B feedback; 4. stimulus-induced elevations in B secretion result in day-time feeding; 5. insensitivity of both caloric efficiency and white fat stores to chronic stress in adrenalectomized, B-clamped rats results from loss of normally variable B levels.     

Absence of a sex difference in algorithms for spatial problem solving

Pairs of stimuli taken from a pscyhometric measure of spatial aptitude were shown to 36 college men and 32 college women. The stimuli in pairs were (a) either identical or mirror images, and (b) presented in orientations that differed by 0–135 deg. Individuals judged, as rapidly as possible, if the stimuli in a pair would be identical or mirror images if presented at the same orientation. Replicating previous work, there was a sex difference in the speed with which problems were solved. Of greater interest was the fact that men and women were quite alike in the frequency with which they used different algorithms to solve the problems. Most individuals solved the problems using an algorithm in which an individual encodes the stimuli in working memory, mentally rotates one stimulus to the orientation of the other, compares both determine if they are identical, and responds. Two variants of this algorithm were also used by some subjects. In one variant, if comparison revealed that the stimuli were dissimilar, individuals did not respond immediately but continued processing until a self- imposed deadline was reached. In another variation, subjects only rotated the comparison stimuli when their orientations exceeded a critical angle.     

A diagrammatic approach to computer instruction for the naive user

There are inherent difficulties with text as an instructional format. This research presents the development of a diagrammatic representation that overcomes some of those difficulties. A simple “language” is presented that includes both procedural and model information. This approach is applied to the instruction of word processing/text-editing skills. An experimental methodology is presented and preliminary results are reported that suggest that the diagrammatic approach results in improvements in both the amount of word processing accomplished and the speed with which modifications are made.     

Unilateral brain lesions and MMPI performance: a preliminary study.

Samples of 15 Ss with right- and 20 Ss with left-hemisphere brain lesions secondary to war-related penetrating missile wounds were matched for age, education, and recency of injury and evaluated with the MMPI. Right-hemisphere lesioned Ss produced a composite profile with all scales within normal limits. In contrast, the composite profile of left-hemisphere lesioned Ss showed significant elevations on the Sc, D, and Hs clinical scales, suggesting increased psychopathological responses in such Ss. Although the general configurations of the composite MMPI profiles in the two samples were similar, significant differences in the elevation of both validity and clinical scales were obtained. The results tend to support previous findings of a depressive-catastrophic reaction in patients with lesions in the dominant hemisphere, while not supporting the euphoric-indifference response in nondominant-hemisphere lesioned Ss.     

The effects of instructional variables on young children's organization and free recall

The relationship between verbal instruction and children's free recall was examined. Sixty first-grade children (mean age 84 months) were trained to categorize pictures of common objects. Half were given organizational instructions emphasizing categorization, and half were given instructions emphasizing the individual objects. Similarly, half were given detailed verbal instructions and encouraged to listen, and half were taught using a question type format that encouraged participation. Immediately and after a 2- to 3-week delay, children who were shown an organizational strategy categorized the materials during study and attained higher recall scores than children who were shown a specific strategy. After the 2- to 3-week delay, children in the explanation groups out-performed children in the question-asking groups. The child's competence as measured by intelligence and performance in school did not contribute to amount recalled when subjects were given instructions emphasizing the general strategy. However, children of high competence benefited more from specific training by recalling more items than did children of low competence. These findings point to the importance of instructional variables in studying changes in children's processing capabilities.