Orbitofrontal cortex and dynamic filtering of emotional stimuli

Event-related potentials (ER) were recorded in response to mildly aversive somatosensory and auditory stimuli. Patients with orbitofrontal lesions exhited enhanced ERPs (i.e., P3 amplitudes), as compared with control subjects. Moreover, these patients did not habituate to somatoensory stimuli across blocks of trials. The results were specific to orbitofrontal damage, since patients with damage to the dorsolateral prefontal cortex did not exhibit enhanced P3 amplitudes. These findings suggest damage to the orbitofrontal cortex impairs the ability to modulate or inhibit neural responses to aversive stimuli. The findings are couched in terms of dynamic filtering theory, which suggests that the orbitofrontal cortex is involved in the selection and active inhibition of neural circuits associated with emotional responses.     

Autonomy,constraining options,and organ sales

Although there continues to be a chronic shortage of transplant organs the suggestion that we should try to alleviate it through allowing a current market in them continues to be morally condemned, usually on the grounds that such a market would undermine the autonomy of those who would participate in it as vendors. Against this objection Gerald Dworkin has argued that such markets would enhance the autonomy of the vendors through providing them with more options, thus enabling them to exercise a greater degree of control over their bodies. Paul Hughes and T. L. Zutlevics have recently criticized Dworkin's argument, arguing that the option to sell an organ is unusual in that it is an autonomy–undermining "constraining option" whose presence in a person's choice set is likely to undermine her autonomy rather than enhance it. I argue that although Hughes' and Zutlevics' arguments are both innovative and persuasive they are seriously flawed — and that allowing a market in human organs is more likely to enhance vendor autonomy than diminish it. Thus, given that autonomy is the preeminent value in contemporary medical ethics this provides a strong prima facie case for recognizing the moral legitimacy of such markets.     

Affective and cognitive modulation of performance monitoring: Behavioral and ERP evidence

This study investigates the effects of negative affect on performance monitoring. EEG was acquired during a lateralized, numeric Stroop working memory task that featured task-irrelevant aversive and neutral pictures between stimuli. Performance accuracy showed a right-hemisphere advantage for stimuli that followed aversive pictures. Response-locked event-related potentials (ERPs) from accurate trials showed an early negative component (CRN; correct response/conflict-related negativity) followed by a positive wave comparable to the Pe (error positivity). The CRN was bi-peaked with an earlier peak that was sensitive to aversive pictures during early portions of the experiment and a later peak that increased with error likelihood later in the experiment. Pe amplitude was increased with aversive pictures early in the experiment and was sensitive to picture type, Stroop interference, and hemisphere of stimulus delivery during later trials. This suggests that ERP indices of performance monitoring, the CRN and Pe, are dynamically modulated by both affective and cognitive demands.     

Examining the potential exploitation of UNOS policies

The United Network for Organ Sharing (UNOS) waiting list was designed as a just and equitable system through which the limited number of organs is allocated to the millions of Americans in need of a transplant. People have trusted the system because of the belief that everyone on the list has an equal opportunity to receive an organ and also that allocation is blind to matters of financial standing, celebrity or political power. Recent events have revealed that certain practices and policies have the potential to be exploited. The policies addressed in this paper enable those on the list with the proper resources to gain an advantage over other less fortunate members, creating a system that benefits not the individual most in medical need, but the one with the best resources. These policies are not only unethical but threaten the balance and success of the entire UNOS system. This paper proposes one possible solution, which seeks to balance the concepts of justice and utility.     

A process-oriented approach for averting confounds resulting from general performance deficiencies in schizophrenia

The most pervasive and least well-addressed problem in cognitive studies of schizophrenia is the propensity of schizophrenia patients to show inferior performance on a variety of cognitive tasks. Consequently, apparent specific cognitive abnormalities may actually reflect the interaction of task discriminating power with generalized deficit. L. J. Chapman and J. P. Chapman (1973a) suggested psychometric approaches for eliminating such artifactual group differences. Unfortunately, their solution neglects important issues of process specification and does not provide a viable strategy for process-oriented investigators. Psychometric remediation of artifactual Group x Task interactions inevitably confounds the processes being measured, resulting in theoretically ambiguous findings. Moreover, evidence that changes in measurement reliability can both increase and decrease group discrimination challenges a basic underlying assumption of the Chapmans' matching solution. This article presents a process-oriented approach to solving this problem in schizophrenia research.     

Breast and Chest Size: Ideals and Stereotypes Through the 1990s

This study investigated differences in ideals and stereotypes associated with breast and chest size through the 1990s. Five cohorts of primarily Caucasian participants between 1990 and 1998 completed the Breast/Chest Rating Scale that consists of figures of men and women of varying upper torso sizes and a series of questions related to ideal size, perceptions of others' ideals, and characteristics associated with different sizes. Although the breast size women perceive as preferred by others has increased, the ideal breast size has remained stable for men and women. Men's ideal breast size was consistently larger than the breast size women prefer, and men also preferred a significantly larger chest size. Despite an increasing cultural emphasis on large chest size, there was a significant decrease in the chest size preferred by women across cohort groups. The chest size men think women prefer, however, has increased. Although there was little evidence of changes in stereotypes associated with chest size, the breast size associated with a variety of positive characteristics was significantly larger in 1998 than in 1992. These results are discussed in relation to body image and social implications.     

Action planning in the presence of distracting stimuli: an investigation into the time course of distractor effects

Humans have a remarkable capability to respond efficiently to a stimulus of interest despite other stimuli competing for neural resources. The current study investigated how the human system copes with distracting stimuli. During each trial, participants viewed 2 sequential stimuli that were each associated with a specific action based on an arbitrary mapping. The 1st stimulus served as a distractor, and the 2nd stimulus required a response (target). When the distractor preceded the target by more than a few hundred milliseconds, response latencies were slower when the 2 stimuli were associated with the same response. The authors propose that this negative compatibility effect stemmed from an inhibitory mechanism that the human system utilizes to prevent the distractor from eliciting an unwanted response.     

Looking at the sunny side of life: age-related change in an event-related potential measure of the negativity bias

Studies of the negativity bias have demonstrated that negative information has a stronger influence than positive information in a wide range of cognitive domains. At odds with this literature is extensive work now documenting emotional and motivational shifts that result in a positivity effect in older adults. It remains unclear, however, whether this age-related positivity effect results from increases in processing of positive information or from decreases in processing of negative information. Also unknown is the specific time course of development from a negative bias to an apparently positive one. The present study was designed to investigate the negativity bias across the life span using an event-related potential measure of responding to emotionally valenced images. The results suggest that neural reactivity to negative images declines linearly with age, but responding to positive images is surprisingly age invariant across most of the adult life span.