The borderline hypertensive rat (BHR): A new model for the study of environmental factors in the development of hypertension

While many studies have attempted to produce hypertension through the use of various environmental Stressors, few have succeeded in producing chronic elevations in blood pressure beyond levels considered to be borderline hypertensive (140–160 mm Hg systolic). The problem with most studies stems from the use of genetically normotensive animals and the selection of Stressors to which animals readily adapt. A new approach is suggested, which recognizes the role of genetics in human essential hypertension. Animals with one hypertensive parent do not develop spontaneous hypertension but show a more sensitive cardiovascular response to environmental Stressors than animals with normotensive parents. Preliminary studies revealed that animals with a mixed genetic history of hypertension develop spontaneous borderline hypertension. When subjected to shock-shock conflict, these borderline hypertensive rats (BHR) developed permanent hypertension that failed to abate even after a ten-week, shock-free recovery period. The hypertension was accompanied by elevated heart weight to body weight ratios and by significant cardiac pathology. Subsequent work has demonstrated that these animals also become hypertensive when fed a high-sodium diet. Finally, in a series of exercise studies, we found that BHRs subjected to a shock stressor were protected against stress-induced hypertension if they exercised daily. The potential of this model for studies of the mechanisms by which environmental variables produce permanent hypertension is discussed.     

Appetitive differential conditioning of the rabbit’s jaw movement response

Two experiments examined appetitive differential conditioning of the rabbit’s jaw movement response (JMR) in a two-phase procedure. The first phase entailed reinforced training with one conditioned stimulus (CS+), and the second phase involved intermixed presentations of CS+ and an unreinforced stimulus (CS?). In Experiment 1, CS+ was a 600-Hz tone, and CS-was either a 660-,1,000-, or 2,100-Hz tone. In Experiment 2, the magnitude of the water unconditioned stimulus (US) paired with CS+ was either 1, 3, or 9 ml. The experiments revealed that 1) the level of responding to CS-rose for several days and then declined over the remainder of training; 2) the physical similarity between CS+ and CS?directly affected the level of responding to CS?but had no discernable effect on the level of responding to CS+ ; and 3) US magnitude positively affected the level of responding to CS + and, to a lesser extent, CS?. The results are discussed in terms of their implications for Spence’s gradient interaction theory and Pavlov’s external inhibition hypothesis.     

Short-term memory processes in counting

Four experiments examined the memory processes used to maintain location in a counting sequence. In Experiment 1, subjects who rapidly counted forward omitted many repeated-digit numbers (e.g., 77), as found previously with backward counting. Subjects in Experiment 2 counted backward with normal auditory feedback or with headphones through which white noise was channeled. In both cases, repeated-digit errors predominated, suggesting that the contents of short-term memory, rather than auditory sensory memory, are checked during counting. In Experiment 3, subjects silently wrote counting responses, and the omission errors resembled those in vocal counting. Repetition errors were also found and attributed to phonological recoding failures. Articulatory suppression in Experiment 4 greatly increased the number of repetition errors in the written counting task. A model of the counting process was proposed according to which subjects keep track of their location in the counting sequence by monitoring phonologically coded short-term memory representations of the numbers.     

A modification in scoring the ABC Scale

The scoring procedures for the Articulation of the Body-Concept (ABC) Scale to use with three-, four- and five-year-old children were modified to determine their degree of field-dependence-independence. A total of 300 children, who obtained a score of one or better on the ABC Scale, were administered the Preschool Embedded Figures Test (PEFT) and the ABC Scale. The ABC Scale was scored using its scoring procedures and the scoring procedures for the Goodenough-Harris Drawing Test (GHDT). Scores on the PEFT, ABC Scale and GHDT were correlated with each other. Correlations among all cognitive measures ranged from .88 to .99, which were high and statistically significant (p < .0001). Therefore, the scoring procedures for the GHDT can be substituted in scoring the ABC Scale in assessing young children's field-dependence-independence.     

Visual short term memory in aphasic patients

The major purpose of this study was to investigate aphasic patients' STM for visual stimuli which are difficult to encode. The effect of a varied information rate and information load per item was tested, and so was the relation between primacy and recency scores. The investigation included memory both for content and for position. Each item group in the tests consisted of a time sequence of squares with internal grid lines and a dot in one of the cells. The location of the dot had to be remembered. Both the aphasic group and the control group included 24 persons matched for age. The aphasic group showed a somewhat lower overall score than the normal group. Apart from the interaction between groups and information load, no signifcant interactions were observed. However, there was a systematic tendency over tests towards a relatively lower recency score in the aphasic group.     

Microcomputer-assisted relaxation

The present pilot study was designed to test the effectiveness of a microcomputer program developed by the authors to induce relaxation and focused attention, which are common to most clinical stress-reduction and hypnotic procedures. A nonclinical sample of 20 adults used the program on an APPLE IIc computer in two 30-min. sessions in a within-subjects design. Repeated measures analyses of variance showed significant decreases in the Spielberger State Anxiety Scale and on a visual analog anxiety scale. Limitations and implications of the study are discussed.     

Geophysical variables and behavior: XXIX. Impact of atmospheric conditions on occurrences of individual violence among Canadian penitentiary populations

This project studied the effects of weather variables and size of the population on minor and major violence rates within six prisons in the Kingston, Ontario, Canada area from January, 1980 through December, 1983. While weather variables have been studied in relation to mood changes within the general population, this study was the first to analyze the impact of weather variables on rates of violence within the prison setting using forward inclusion multiple regression. Analysis showed that population size consistently appeared positively correlated with assaults on other inmates among the male medium-security prisoners during the summer months. In the summer months, temperature tended to be positively related to some minor kinds of offenses, but in the winter months the relationship was negative. Humidity, rain, sunshine hours, snow, and snow on the ground were not consistently related to incidences of minor and major violence. Indices of geomagnetic disturbances had statistically significant inverse relationships with attempted suicide/self-inflicted injury rates among the male prisoners during the summer months. Over 12 months, wind was generally negatively correlated with incidences of major and minor violence among the male inmates. For 6-mo. periods, wind was generally positively correlated with violence rates during the winter months and negatively correlated during the summer months among the male inmates. The findings relating weather variables to violence rates in the women's prison were consistently in opposition to those found for male prisoners during the 4-yr. period.