Reconciling the influence of task-set switching and motor inhibition processes on stop signal after-effects.

Executive response functions can be affected by preceding events, even if they are no longer associated with the current task at hand. For example, studies utilizing the stop signal task have reported slower response times to "GO" stimuli when the preceding trial involved the presentation of a "STOP" signal. However, the neural mechanisms that underlie this behavioral after-effect are unclear. To address this, behavioral and electroencephalography (EEG) measures were examined in 18 young adults (18-30 years) on "GO" trials following a previously "Successful Inhibition" trial (pSI), a previously "Failed Inhibition" trial (pFI), and a previous "GO" trial (pGO). Like previous research, slower response times were observed during both pSI and pFI trials (i.e., "GO" trials that were preceded by a successful and unsuccessful inhibition trial, respectively) compared to pGO trials (i.e., "GO" trials that were preceded by another "GO" trial). Interestingly, response time slowing was greater during pSI trials compared to pFI trials, suggesting executive control is influenced by both task set switching and persisting motor inhibition processes. Follow-up behavioral analyses indicated that these effects resulted from between-trial control adjustments rather than repetition priming effects. Analyses of inter-electrode coherence (IEC) and inter-trial coherence (ITC) indicated that both pSI and pFI trials showed greater phase synchrony during the inter-trial interval compared to pGO trials. Unlike the IEC findings, differential ITC was present within the beta and alpha frequency bands in line with the observed behavior (pSI > pFI > pGO), suggestive of more consistent phase synchrony involving motor inhibition processes during the ITI at a regional level. These findings suggest that between-trial control adjustments involved with task-set switching and motor inhibition processes influence subsequent performance, providing new insights into the dynamic nature of executive control

How Not to Think About Managed Care

The claim of this Article is that the concept of managed care, like many concepts now prominent in commentary about medical care finance and delivery in the United States, is incoherent and thus a barrier to useful analysis. To demonstrate this conclusion, we first discuss the managerial context in which managed care claims have arisen and outline the diverse trends to which the category is regularly and confusingly applied. We then suggest an alternative approach to characterizing recent changes in medical care and show how this approach alters and deepens our understanding of recent economic and political developments. We conclude by arguing for more neutral categories to make sense of past and projected developments in methods of reimbursement, techniques of management, and organizational structures

Validity of the lifetime drinking history: A comparison of retrospective and prospective quantity-frequency measures

OBJECTIVE: The Lifetime Drinking History (LDH) has been used to examine alcohol use throughout the life span. Given its retrospective nature, it is important to examine the validity of the assessment. METHOD: Building on previous work establishing the reliability and validity of the LDH, the current study examined a sample of 1,295 men in the Vietnam Era Twin Registry. The men were assessed retrospectively with the LDH in 2000, at an average age of 51. The drinking patterns of these same men were also assessed prospectively in four prior studies, taking place in 1987, 1990, 1992, and 1995. RESULTS: Validity of the LDH was examined by comparing the correspondence between the prospective and retrospective quantity-frequency measures and reported age at first regular drinking. Correlations between the retrospective and prospective assessments were high for age at first regular drinking (.42-.58) and quantity-frequency measures (.47-.69), although some mean differences in the amount of consumption existed. CONCLUSIONS: Results support the use of the LDH in reporting phases of drinking across the life span