The impact of aerobic activity on cognitive function in older adults: A new synthesis based on the concept of executive control

Numerous reaction time studies have suggested that age-related declines in cognitive function might be ameliorated by lifestyles involving aerobic activity or by interventionist programmes of aerobic exercise. These studies are far from conclusive, however, reflecting a failure to factor out cognitive from sensory and motor processes. Following a critical review of the literature, we report on recent developments that differentiate cognitive processes involving executive vs non-executive control, the former being associated with frontal lobe function. Three key studies suggest that aerobic exercise primarily improves executive control.     

Procedural justice in the context of civil commitment: an analogue study

Procedural justice theory posits that the process by which disputes are resolved influences perceptions of fairness and satisfaction with outcomes, even if the outcomes are unfavorable. Within the context of civil commitment, Tyler (1992) has suggested that enhancing respondents' perceptions of procedural justice (i.e., participation, dignity, and trust) during commitment proceedings might facilitate accommodation to an adverse judicial determination (i.e., commitment) and subsequently enhance therapeutic outcomes. The study reported here used videotapes of mock commitment hearings to examine whether patients committed for involuntary treatment are sensitive to procedural justice manipulations. Results suggest that patients are sensitive to procedural justice manipulations and, further, that such manipulations are likely to influence the patients' attitude toward psychiatric care. These findings suggest that the development of strategies to enhance patients' perceptions of procedural justice in commitment hearings may indeed have positive therapeutic implications and warrants further investigation.     

The acquisition of an appetite

Unlike older animals, weanling-age rats do not seek water to drink when they are dehydrated, despite the fact that a physiological sensitivity to dehydration is present very soon after birth. We demonstrate here that the appetitive behaviors needed to approach and obtain water become linked to dehydration only as a result of specific postnatal learning experience. Preventing early experience with dehydration retards the developmental emergence of dehydration-induced, water-oriented behavior in young rats. But a single pairing of water with dehydration can establish an appetitive response. These findings reveal a critical role of early learning in the development of goal-oriented behavior. Such a learning process is potentially characteristic of other behavioral systems, from the most basic appetites to complex motives.     

Cone excitation ratios correlate with color discrimination performance in the horse (Equus caballus)

Six horses (Equus caballus) were trained to discriminate color from grays in a counterbalanced sequence in which lightness cues were irrelevant. Subsequently, the pretrained colors were presented in a different sequence. Two sets of novel colors paired with novel grays were also tested. Performance was just as good in these transfer tests. Once the horse had learned to select the chromatic from the achromatic stimulus, regardless of the specific color, they were immediately able to apply this rule to novel stimuli. In terms of the underlying visual mechanisms, the present study showed for the first time that the spectral sensitivity of horse cone photopigments, measured as cone excitation ratios, was correlated with color discrimination performance, measured as accuracy, repeated errors, and latency of approach.     

Rethinking professional ethics in the cost-sharing era

Changes in healthcare financing increasingly rely upon patient cost-sharing to control escalating healthcare expenditures. These changes raise new challenges for physicians that are different from those that arose either under managed care or traditional indemnity insurance. Historically, there have been two distinct bases for arguing that physicians should not consider costs in their clinical decisions--an "aspirational ethic" that exhorts physicians to treat all patients the same regardless of their ability to pay, and an "agency ethic" that calls on physicians to be trustworthy advisors to their patients. In the setting of greater patient cost-sharing, physicians' aspiration and agency roles increasingly conflict. Satisfactorily navigating the new terrain of consumer-driven healthcare requires physicians to consider these two roles and how they can best be reconciled so as to maximize quality of care while respecting the heterogeneity of patients' financial resources and willingness to pay.     

Referential communication disturbances in the speech of nonschizophrenic siblings of schizophrenia patients

Several different types of communication disturbances have been identified in the speech of schizophrenia patients. This study assessed 6 types of referential communication disturbances in the speech of 32 stable outpatients, 23 of their nonschizophrenic siblings, and 27 control subjects. The siblings made more frequent reference failures of all types than control subjects and did not differ from the patients on most types of disturbance. Only on the arguably most "schizophrenic" type of disturbance, the missing information reference, did patients show more deviance than siblings. On the vague reference, siblings showed more deviance than patients. These results, which are very similar to those previously reported on parents of patients, support the idea that referential disturbances reflect vulnerability to schizophrenia.     

Heart rate and ratings of perceived exertion during treadmill and elliptical exercise training

Elliptical exercise has recently increased in popularity. However, little is known regarding heart rate and perceptual responses during this exercise mode even though such information is important with respect to prescribing and regulating exercise intensity. In the current study, heart rate and perceived exertion were compared between treadmill and elliptical exercise. During treadmill exercise (TM(EST)) participants estimated RPE-Overall as well as RPE-Legs and RPE-Chest. Two elliptical sessions followed: (1) RPE estimation during elliptical exercise (EL(EST)): HR (b/ min.) from TM(EST) was achieved during elliptical exercise, with participants estimating RPE-Overall, RPE-Legs, and RPE-Chest. (2) RPE production during elliptical exercise (EL(PROD)): RPE-Overall from TM(EST) was produced during elliptical exercise. There were no significant differences between modes for RPE-Overall (TM(EST): 11.2 +/- 2.2 vs EL(EST): 11.9 +/- 3.2) or RPE-Chest (TM(EST): 11.0 +/- 2.4 vs EL(EST): 11.7+/- 3.2). Mean RPE-Legs was significantly different (TM(EST): 11.2 +/- 2.4 vs EL(EST): 12.5 +/- 3.1). Heart rate was not significantly different between TM(EST) (163 +/- 16.6) and EL(PROD) (159 +/- 20.0). Analysis indicated elliptical exercise is perceived as more intense with respect to leg (RPE-Legs) exertion. Further, RPE-Overall appears effective for regulating heart rate during elliptical exercise.     

Effects of self-evaluation on the P300 event-related potential

The effects of self evaluation on the P300 event-related potential (ERP) were explored with 56 participants (16 men, 40 women; M age = 23.4 yr., SD = 1.2) across three conditions. The conditions included (1) a standard ERP auditory oddball discrimination between a random target (15% occurrence) and standard stimuli (85% occurrence), (2) the oddball task followed by the additional cognitive task of maintaining a mental count of the target tones, and (3) the oddball task followed by the additional cognitive task of self-evaluating whether they felt surprised by the current occurrence of the target tone. The added cognitive requirements for Conditions 2 and 3 required the subjects to maintain a cognitive readiness for the secondary stimulus-related task during their sensory discrimination response for the standard oddball task. During the self-evaluation condition, the P300 amplitude was significantly larger across all recording locations than the regular oddball condition and the cognitive count condition.     

Physician-patient relations: no more models

Currently, the common theoretical models of "preferred" decision-making relationships do not correspond well with clinical experience. This interview study of congestive heart failure (CHF) patients documents the variety of patient preferences for decision-making, and the necessity for attention to family involvement. In addition, these findings illustrate the confusion as to the designation of surrogate decision-makers and physicians in charge. We conclude that no single model of physician-patient decision-making should be preferred, and that physicians should first ask patients how they want medical information and decision-making to be handled.