Response of joint capsule neurons to axial stress and strain during dynamic loading in cat

1. Experiments were conducted to test the hypothesis that the responses of joint capsule mechanoreceptors better encode tissue stress or tissue strain. The experimental model was a small ligament from the cat knee capsule, which was stretched uniaxially in vitro. Experiments were done with either force or displacement as the controlled variable, and with steps, sinusoids, or pseudorandom Gaussian noise (PGN) as the input function. 2. The strength of coupling between neural discharge and both strain and stress was quantified during step experiments using linear correlation coefficients. The correlation between the frequency of neural discharge and stress was 0.93 +/- 0.09 (SD). The correlation between frequency of neural discharge and strain was -0.91 +/- 0.06. The magnitudes of these correlation coefficients were not significantly different. 3. The strength of coupling between neural discharge and both strain and stress during sinusoidal and PGN experiments was quantified by the use of an information theoretic statistic, transinformation. Out of 282 sinusoidal runs, transinformation between neural discharge and stress was significantly greater than transinformation between strain and neural discharge 241 times. Transinformation between strain and neural discharge was significantly greater 15 times. 4. During PGN experiments, transinformation between stress and neural discharge was greater than transinformation between strain and neural discharge in all 19 experimental runs. 5. Conditional transinformation between strain and neural discharge, given stress, was calculated for all sinusoidal and pseudorandom experiments. This statistic was greater than zero in 268 out of 289 experimental runs, indicating that a component of strain independent of stress is being signaled in the neural discharge.     

Religious orientation, aging, and blood pressure reactivity to interpersonal and cognitive stressors

Background: Research on religion and health suggests general health benefits for those who are more religiously involved. Particular aspects of religiosity that may influence this finding, however, have not been sufficiently investigated.Purpose: This study was designed to explore the relationship between religious orientation (intrinsic, extrinsic) and blood pressure reactivity among older (over 60 years) and younger (18–24 years) adults exposed to two qualitatively different laboratory stressors (cognitive, interpersonal).Methods:Participants were categorized as exhibiting either a predominately intrinsic or extrinsic religious orientation based on scores on the Religious Orientation Scale. They were subsequently exposed (in counterbalanced order) to two laboratory stressors that varied in terms of whether an interpersonal confrontation was involved. Measures of blood pressure were obtained at baseline and during stressor presentation.Results: Analyses indicated that older extrinsically religious individuals demonstrated exaggerated reactivity compared to younger participants and older intrinsically religious individuals. Older intrinsically religious participants did not differ from younger persons. Similar results were found for analysis of baseline data. Extrinsic participants had greater reactivity during the interpersonal confrontation condition than did intrinsic individuals.Conclusions: These findings suggest that religious orientation may be an important variable to study regarding cardiovascular reactivity in, particularly, older adults. This research was supported in part by National Institute on Aging Grant 1 R03 AG 18554-01. A previous version of this article was presented in August 2002 as a Citation Paper at the 110th Annual Convention of the American Psychological Association, Chicago. We thank Timothy W. Smith, James A. Blumenthal, Carl E. Thoresen, and Edward M. Heath for their assistance throughout this project. We also thank Llewellyn Jones and Jodi Hildabrandt for their efforts in collecting data.     

Benefits from peer teaching in the dental gross anatomy laboratory

This study examined the impact of implementing a rotating dissection schedule on the attitudes and performance of first-year dental students in the gross anatomy laboratory at the University of Kentucky. In 2002-2003, half of the students assigned to each cadaver dissected the assigned objectives during the first 90 min of the laboratory session. During the last 30 min, the non-dissecting group members came into the laboratory and had the day's dissection demonstrated and explained to them via peer instruction. Dissection responsibilities rotated with each laboratory session. Eighty-eight percent of student participants were satisfied with the rotating dissection approach according to a mid-term survey, and this satisfaction level remained unchanged at the end of the semester for most students. Students' perceptions of the quality of peer laboratory presentations varied, with only 44% rating them as good or better. Eighty percent of students perceived that rotating dissection did not impede their performance, and this was confirmed by analysis of grade data. Student satisfaction and the ability to devote additional weekly curriculum time to studying anatomy in a very compressed curriculum were the main student-described benefits.     

The Survey of Recent Life Experiences: A decontaminated hassles scale for adults

A new decontaminated hassles measure for adults, the Survey of Recent Life Experiences, was developed and validated. An initial pool of 92 items was administered to 100 subjects along with the Perceived Stress Scale. Fifty-one items were selected, based on significant correlations with the latter scale. The alpha reliability of the resultant final form of the Survey of Recent Life Experiences and its correlation with perceived stress were both high. In a separate cross-replication sample of 136 adults, the alpha reliability of the Survey and its correlation against the Perceived Stress Scale remained acceptably high. Moreover, separate-sex analyses supported the reliability and validity of the Survey of Recent Life Experiences across gender. Factor analysis of the Survey yielded six interpretable factors. Intercorrelations among subscales based on these factors were generally modest, suggesting that the scale is relatively free from contamination by psychological distress.The work reported was facilitated by a grant from the Social Sciences and Humanities Research Council of Canada's Small Grant Program, administered by the Office of Research Administration, York University. The authors appreciate the cooperation of staff at the Ontario Science Centre, Toronto, and the assistance of Maria Gurevich in verifying the data.