Tube feedings and persistent vegetative state patients: ordinary or extraordinary means?

This article looks at the late John Paul II's allocution on artificial nutrition and hydration (ANH) and the implications his statement will have on the ordinary-extraordinary care distinction. The purpose of this article is threefold: first, to examine the medical condition of a persistent vegetative state (PVS); second, to examine and analyze the Catholic Church's tradition on the ordinary-extraordinary means distinction; and third, to analyze the ethics behind the pope's recent allocution in regards to PVS patients as a matter of conscience. Rather than providing clarification, I argue that the papal allocution has raised many difficult questions. People in situations where decisions must be made about withdrawal or continued ANH are in need of guidance. Moreover, additional analysis is needed to determine whether the papal allocution is in conflict with the traditional Catholic medical ethics understanding of the ordinary-extraordinary care distinction.     

Abrupt, but not gradual visuomotor distortion facilitates adaptation in children with developmental coordination disorder

A previous experiment investigating visuomotor adaptation in typically developing children and children with Developmental Coordination Disorder (DCD) suggested poor adaptation to an abruptly induced visuomotor perturbation. In the current study, using a similar center-out drawing task, but administering either an abrupt or a gradual perturbation, and twice as many adaptation trials, we show that typically developing children are well able to successfully update an existing internal model in response to a 60 degrees rotation of the visual feedback, independent of the perturbation condition. Children with DCD, however, updated their internal map more effectively during exposure to an abrupt visuomotor perturbation than to a gradual one. This may suggest that the adaptation process in children with DCD responds differently to small vs. large steps of visuomotor discrepancies. Given the known role of the cerebellum in providing an error signal necessary for updating the internal model in response to a gradual visuomotor distortion, the results of our study add to the growing body of evidence implicating compromised cerebellar function in DCD.     

Post-training Unilateral Vagal Stimulation Enhances Retention Performance in the Rat

Many peripherally administered substances which modulate memory do not freely enter the brain. Such compounds may act through peripheral receptors that send messages centrally through vagal afferents. To explore this hypothesis, rats were chronically implanted with cuff electrodes on the left cervical vagus nerve. Each animal was trained 48 h after surgery on a one-trial inhibitory-avoidance task with a 0.75-mA, 1.0-s footshock. Immediately following training, each animal received either no stimulation or vagal stimulation (0.5-ms biphasic pulses; 20 Hz, 30 s) at one of three intensities (0.2, 0.4, 0.8 mA; eight animals per group). Retention was tested 24 h later. Neither the 0.2-in or 0.8-mA groups (22.1-s; 53.7-s median latency) showed altered retention performances, whereas the 0.4-mA group showed significantly improved retention (881.0 s) compared to unstimulated controls (21.1 s; U = 6, p < .01). This inverted-U shaped function indicates that vagal activation during memory consolidation modulates retention for memory tasks.     

Judging up and down.

In Experiment I subjects were asked to judge whether an arrow was pointing up or pointing down at various heights inside a surrounding rectangle. They were faster on an arrow pointing up the higher it was in the rectangle, and they were faster on an arrow pointing down the lower it was in the rectangle. Experiments 2, 3, and 4 were designed to test sources for this"congruity effect." The intrusive height information for each arrow was assumed to facilitate or interfere with (a) the activation of the correct motor response; (b) the maintenance of the implicit instruction "Is it pointing up, or is it pointing down?"; or (c) the selection of the criterial perceptual information as a basis for the response. All three experiments were consistent with c, but not with a or b. Indeed, the results contrasted with previous demonstrations of the Stroop effect in certain critical features.     

The power law for the perception of rotation by airline pilots

The purpose of this study was to determine the power laws for the perception of rotation about the three major body axes. Eighteen airline pilots made magnitude estimates of 5-sec pulses of nine angular accelerations having a range of acceleration x time of 10–150 deg/sec. The results showed that (1) the power law with an exponent of 1.4 describes the subjective motion of these pilots for all three major body axes, (2) the power law also describes the perception of motion for individual pilots with a substantial range of exponents, (3) there were significant correlations among the exponents for the three body axes, and (4) the data suggest that the power law over the wide range used may be more complex than implied by a formula with a single exponent.     

The social sources of the current religious revival

Conclusion It has been contended that the current revival of interest in religion cannot be explained only in terms of the search for meaning and security in the face of the anxieties associated with social disruption. Other social forces of our time seem also to have stimulated the current revival and seem to be operative in its maintenance. Four of these forces have been specified, examined, and analyzed in this paper. It has not been intended through the drawing of these interpretations to suggest that, in his rediscovery of religion, the individual may not also be influenced by more universal and, depending upon one's values, possibly more appealing motives.     

Toward DSM-V and the classification of psychopathology

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) developed by the American Psychiatric Association (1994) is a compelling effort at a best approximation to date of a scientifically based nomenclature, but even its authors have acknowledged that its diagnoses and criterion sets are highly debatable. Well-meaning clinicians, theorists, and researchers could find some basis for fault in virtually every sentence, due in part to the absence of adequate research to guide its construction. Some points of disagreement, however, are more fundamental than others. The authors discuss issues that cut across individual diagnostic categories and that should receive particular attention in DSM-V: (a) the process by which the diagnostic manual is developed, (b) the differentiation from normal psychological functioning, (c) the differentiation among diagnostic categories, (d) cross-sectional vs. longitudinal diagnoses, and (e) the role of laboratory instruments.     

Free operant avoidance as a function of the response-shock=shock-shock interval

Two temporal parameters of free operant or Sidman avoidance behavior are the interval by which responses postpone shocks (Response-Shock interval) and the interval between shocks when no responses occur (Shock-Shock interval). Avoidance behavior was examined in three white rats under conditions where the Response-Shock and Shock-Shock intervals were always equal. With intervals from 10 to 60 sec response rates and shock rates were similar, decreasing, negatively accelerated functions of increasing Response-Shock=Shock-Shock interval. Over this range, response and shock rates were linearly related to the reciprocal of the Response-Shock=Shock-Shock interval. It was shown, however, that this relation cannot hold at extremely long intervals. Both the ratio of responses emitted to shocks received and the percentage of shocks possible which were avoided increased at long Response-Shock=Shock-Shock intervals. These findings may be related to the fact that long intervals provide optimal conditions for conditioning avoidance behavior in the rat.     

Schedules of food postponement: II. Maintenance of behavior by food postponement and effects of the schedule parameter

In Experiment I, food-deprived, feeder-trained squirrel monkeys pressed a lever to postpone brief electric shocks (Response-Shock=Shock-Shock interval=30 seconds). Forty-one three-hour sessions of shock postponement were followed by 120 sessions of concurrent shock and food postponement. The shock schedule was unchanged and the food schedule was Response-food interval–20 seconds, Food-food interval 10 seconds. After concurrent shock and food postponement, the shock schedule was discontinued and 40 sessions of food postponement ensued, followed by 53 sessions of extinction. After extinction, food postponement was resumed for 11 sessions. Stable responding with low food rates was maintained under food-postponement after the concurrent schedule. Responding decreased to low levels under extinction and recovered immediately to previous levels when the food-postponement schedule was re-instated. In Experiment II, a parameter of the food-postponement schedule was studied sequentially. Using the same subjects, the Response-food–Food-food interval was manipulated from four seconds to 80 seconds with several orders of presentation. Relations of response rates and food rates to the parameter were similar to those seen under shock postponement. Exposure to very short postponement times (four seconds), resulting in very high food rates, decreased but did not abolish subsequent responding at longer postponement times. Results are discussed from the point of view that reinforcing functions of stimuli consequent on responding depend on a prior history of scheduled contact with those stimuli.