The bradycardia of the dive reflex—A possible mechanism of sudden death

Slowing of the heart rate as part of an oxygen-conserving reflex has been observed in man when breath-holding with the face under water. Emotionally significant situations were found capable of either inhibiting or facilitating the reflex, thus placing the mechanism under the control of the cerebral hemispheres. Indeed, features of the reflex have been induced in human subjects during attempts to penetrate the brachial artery with a hypodermic needle and in association with a mild startle reaction. The latter was observed to a striking degree in four subjects who subsequently died of recurrent myocardial infarction. It is suggested that a protective response designed to conserve oxygen may be inappropriately involved under a variety of circumstances and may be lethal if excessive or if unbalanced by opposing forces.     

Competing on all fronts: Achievement orientation and disordered eating

Strikingly high prevalence rates of symptoms of disordered eating among college women have been documented. The question arises as to whether one aspect of the college experience, achievement orientation, is associated with disordered eating. Competing hypotheses may be generated regarding the relationship between achievement orientation and disordered eating, with arguments for either a positive or negative relationship. The Work and Family Orientation Questionnaire (WOFO) and the Disordered Eating Symptoms Scale (DESS) were administered to 668 female undergraduate college students. Multivariate analysis of the WOFO subscales revealed that women with high levels of disordered eating obtained significantly higher scores on the Competitiveness subscale than women with low DESS scores. These findings support hypotheses of a positive relationship between competitiveness and disordered eating.     

Determinants of Self-Protective Behavior: Home Radon Testing

This field experiment explored the use of informational brochures to encourage home radon testing. Homeowners ( N = 271) received a radon brochure, a questionnaire, and a form for ordering a $20 radon test kit. The brochures differed in their presentations of the magnitude of the threat (varying risk likelihood and severity) and the difficulty of reducing radon levels. Some also included a detailed list of home radon risk factors. Combinations of these three variables yielded a 2 × 2 × 2 factorial design. Although 19.2% of the sample ordered tests, the percentage was constant across brochures. Data from the questionnaire showed that self-reported risk likelihood, risk seriousness, and concern were strongly correlated with intentions to test and with actual test orders. Calculations revealed that although the threat manipulation had a highly significant effect on these risk perceptions, the effect was too small to produce different rates of test orders. Confirming previous radon studies, perceived mitigation difficulty proved unrelated to interest in radon testing.     

The effects of muscle tension on cerebral circulation in blood-phobic and non-phobic subjects

This study aimed to assess whether (1) a muscle tensing procedure which has been found to be useful in the treatment of blood-phobic patients produces an increase in heart rate and cerebral blood flow and (2) whether this increase is greater than that produced by mental effort alone. Subjects were 17 volunteers with a history of fainting in response to blood-injury stimuli, (12 were phobic) and 8 volunteers with no fainting history. They were required to (a) rest, (b) do mental arithmetic, and (c) repeatedly tense and release their arm and leg muscles. It was found that Ss, heart rate and cerebral blood flow velocity were significantly greater during the muscle tensing procedure than during mental arithmetic or resting conditions. The increased cerebral blood flow produced by muscle tensing may enable blood phobic patients to prevent fainting during exposure treatment.     

Letters From V: Adolescent Personality Development in Sociohistorical Context

Systematic content analysis of personal documents is used to assess the course of personality development in one adolescent female exposed to traumatic historical and personal events, as well as more normative life changes. Seventy-one letters written by a young girl to her former teacher over a 9-year period comprise the data for this study. Our analyses assess the normal developmental processes of preoccupation with identity formation and the establishment of intimate relationships, as well as responses to life changes (emigration, marriage, pregnancy). Overall, results suggest that despite serious challenges and losses, this individual experienced normal personality development throughout her trying adolescence. In addition, particular life events affected the course of that development. Factors which may have facilitated her resilience are discussed.     

Identification of time-compressed sentential stimuli by good vs poor readers

Ability of eight good and eight poor readers (in Grade 1, ages ranging from 6.7 to 7.4 yr.) to discriminate phonemic contrasts presented in 50% time-compressed sentential stimuli (Subtest 13 of the Carrow-Auditory Visual Abilities Test) was measured. Good readers exhibited a significantly higher over-all mean performance than poor readers on the time-compressed task. Effects of time-compression on the perception of manner, place, voicing and frequency contrasts showed a similar pattern of errors for both groups of readers. Implications of the effects of auditory discrimination on reading abilities are discussed.     

Processing speed and mental retardation: Deadline procedures indicate fixed and adjustable limitations

Brewer and Smith (1984) showed that control mechanisms mediating speed-accuracy regulation contribute to retarded-nonretarded differences in processing speed, with poorly controlled trial-to-trial RT adjustments underlying the greater RT variability of retarded individuals. In Experiment 1, response deadlines controlled processing time, thus minimizing the influence of such control mechanisms. The obtained speed-accuracy relations showed that retarded subjects were unable to match nonretarded subjects' accuracy when responding as rapidly, thus indicating structural limitations on processing speed. The results of Experiment 2 showed, however, that significant adjustments to retarded subjects' processing speed--exceeding those produced by practice--are achievable. Extended training at a short deadline led to tighter control of RT adjustments, with substantial improvements in mean RT when subjects transferred to a self-paced RT task.     

Effects of transient coronary artery occlusion on canine intrinsic cardiac neuronal activity

In order to further elucidate the regulatory function of canine epicardial neurons, the effects of transient coronary artery occlusion on their spontaneous activity was studied. Fifty-eight individual, spontaneously active units were identified by means of their action potential configurations in specific loci of atrial and ventricular epicardial fat of 10 anesthetized dogs. The activity of 49 of the units was modified by one minute of coronary artery occlusion. Twenty-four of the 49 responding units exhibited increased activity and 37 decreased activity during coronary artery occlusions. Activity changes were sometimes, but not always, associated with decreased left ventricular intramyocardial systolic pressure. During reperfusion, the activity of 6 units was increased compared to control levels, even though ventricular pressures remained the same. Following acute decentralization, 48% of previously active units generated spontaneous activity; the activity of 89% of these was altered during coronary artery occlusion despite the fact that overall cardiodynamics were unchanged. Following hexamethonium administration, the activity generated by 9 of 10 spontaneously active units was modified by coronary artery occlusion. It is concluded that transient coronary artery occlusion can modify the activity generated by intrinsic cardiac neurons, such modification involving central and peripheral neuronal interactions.